A&p Ch. 18 - Heart & Cardiovascular Function

Reviewed by Editorial Team
The ProProfs editorial team is comprised of experienced subject matter experts. They've collectively created over 10,000 quizzes and lessons, serving over 100 million users. Our team includes in-house content moderators and subject matter experts, as well as a global network of rigorously trained contributors. All adhere to our comprehensive editorial guidelines, ensuring the delivery of high-quality content.
Learn about Our Editorial Process
| By Seres21e
S
Seres21e
Community Contributor
Quizzes Created: 15 | Total Attempts: 42,476
| Attempts: 692 | Questions: 154
Please wait...
Question 1 / 154
0 %
0/100
Score 0/100
1. Which of the following would you expect to have the lowest resting heart rate?

Explanation

A trained athlete would be expected to have the lowest resting heart rate because regular exercise and physical conditioning can lead to a stronger and more efficient heart. As a result, the heart does not have to work as hard to pump blood throughout the body, leading to a lower resting heart rate.

Submit
Please wait...
About This Quiz
A&p Ch. 18 - Heart & Cardiovascular Function - Quiz

The heart is more than just an instrument of love – it’s the most important organ in our bodies, beating blood all around and ensuring we keep ticking away like a fully functioning clock. What do you know about it? Take this quiz on A&P Ch. 18 – Heart &... see moreCardiovascular Function now! see less

2. Heart rate is controlled by neurons of the cardiovascular center located in the

Explanation

The correct answer is medulla oblongata. The medulla oblongata is responsible for controlling and regulating many vital functions of the body, including heart rate. It contains the cardiovascular center, which consists of specialized neurons that receive signals from the body and adjust the heart rate accordingly. These neurons can increase or decrease the heart rate in response to various factors such as stress, exercise, or changes in blood pressure. Therefore, the medulla oblongata plays a crucial role in maintaining the appropriate heart rate to meet the body's needs.

Submit
3. When will the blood pressure be greater?

Explanation

When the peripheral vessels constrict, it causes the blood vessels to narrow, resulting in an increase in blood pressure. This is because the constriction of the vessels increases the resistance to blood flow, forcing the heart to pump harder to maintain the same level of blood flow. As a result, the blood pressure rises. Conversely, when the peripheral vessels dilate, the blood vessels widen, reducing the resistance to blood flow and leading to a decrease in blood pressure. Therefore, the blood pressure will be greater when the peripheral vessels constrict.

Submit
4. The heart is innervated by ________ nerves.

Explanation

The heart is innervated by both parasympathetic and sympathetic nerves. The parasympathetic nervous system, through the vagus nerve, slows down the heart rate and decreases the force of contractions. On the other hand, the sympathetic nervous system, through the cardiac accelerator nerves, increases the heart rate and enhances the force of contractions. Therefore, both systems work together to regulate the heart's activity and maintain proper functioning.

Submit
5. Arteriosclerosis can lead to

Explanation

Arteriosclerosis is a condition characterized by the hardening and narrowing of the arteries due to the buildup of plaque. This can lead to hypertension, which is high blood pressure, as the narrowed arteries make it harder for blood to flow through them. Additionally, the plaque buildup can cause blockages in the arteries supplying blood to the brain, leading to a stroke. Furthermore, if the coronary arteries, which supply blood to the heart, are affected by arteriosclerosis, it can result in coronary artery disease, which can lead to chest pain, heart attacks, and other heart-related problems. Therefore, all of the above conditions can be caused by arteriosclerosis.

Submit
6. Which of the following affects blood flow through the body?

Explanation

Blood flow through the body is affected by several factors. Blood viscosity refers to the thickness or stickiness of the blood, which can impede its flow. Vessel diameter plays a significant role as narrower vessels result in increased resistance to blood flow. Turbulence occurs when blood flows irregularly, causing disruptions in the smooth flow. Vascular resistance refers to the overall resistance encountered by blood as it flows through the blood vessels. Therefore, all of these factors (blood viscosity, vessel diameter, turbulence, and vascular resistance) affect blood flow through the body.

Submit
7. Which of the following are characteristics of cardiovascular regulation?

Explanation

The characteristics of cardiovascular regulation include blood flow through tissues meeting the demand for oxygen and nutrients, blood flow changing to match tissue responses, and these changes occurring without drastically altering blood pressure.

Submit
8. The ________ ventricle has a greater workload than the ________.

Explanation

The left ventricle has a greater workload than the right ventricle. This is because the left ventricle is responsible for pumping oxygenated blood to the rest of the body through the systemic circulation, which requires more force. The right ventricle, on the other hand, pumps deoxygenated blood to the lungs for oxygenation, which requires less force. Therefore, the left ventricle has a higher workload compared to the right ventricle.

Submit
9. The hormone that produces cardiovascular effects similar to activation of the sympathetic nervous system is:

Explanation

Epinephrine is the correct answer because it is a hormone that is released by the adrenal glands during times of stress or excitement. It activates the sympathetic nervous system, which is responsible for the "fight or flight" response. Epinephrine increases heart rate, constricts blood vessels, and raises blood pressure, all of which are cardiovascular effects similar to the activation of the sympathetic nervous system. Acetylcholine, bradykinin, tachykinin, and sympathetic neuropeptide do not produce these specific cardiovascular effects.

Submit
10. When the left ventricle contracts, the diameter of the ventricular chamber

Explanation

During left ventricle contraction, also known as systole, the myocardium contracts, causing the ventricular chamber to decrease in size. This reduction in diameter ensures that blood is forcefully ejected into the aorta and circulated to the rest of the body. The contraction of the left ventricle helps maintain blood pressure and facilitates efficient blood flow throughout the cardiovascular system. Therefore, the correct answer is that the diameter of the ventricular chamber decreases during left ventricle contraction.

Submit
11. Stroke volume depends on

Explanation

Stroke volume is the amount of blood pumped out of the heart with each beat. It is influenced by multiple factors, including end-diastolic volume, which is the amount of blood in the ventricles at the end of diastole. A higher end-diastolic volume allows for a greater stretch of the ventricles, resulting in a more forceful contraction and increased stroke volume. The contractility of the ventricle also plays a role in stroke volume, as a stronger contraction can pump out more blood. Additionally, the pressure required to pump blood into the aorta affects stroke volume, as higher pressure can help push more blood out of the heart. Therefore, all of these factors contribute to determining stroke volume.

Submit
12. In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the

Explanation

The correct answer is mediastinum. The question is asking for the region in the middle of the thoracic cavity that is occupied by various structures including the heart, great vessels, thymus, esophagus, and trachea. This region is known as the mediastinum. The other options, such as pleural space, pericardial space, cardiac notch, and ventral cavity, do not accurately describe this specific region in the thoracic cavity.

Submit
13. The atrioventricular valves permit blood flow

Explanation

The atrioventricular valves are located between the atria and ventricles of the heart. Their main function is to prevent the backflow of blood from the ventricles back into the atria during ventricular contraction. This ensures that blood flows in one direction only, from the atria to the ventricles.

Submit
14. When the semilunar valves close, the AV valves then

Explanation

When the semilunar valves close, it indicates the end of ventricular systole and the beginning of ventricular diastole. During this phase, the atria fill with blood and the pressure inside the ventricles decreases. As a result, the AV valves open, allowing blood to flow from the atria into the ventricles. Therefore, the correct answer is "open."

Submit
15. Which of the following would have the greater effect on vascular resistance?

Explanation

Decreasing the diameter of a blood vessel by ½ would have a greater effect on vascular resistance compared to doubling the length of a blood vessel. Vascular resistance is directly proportional to the length of the blood vessel and inversely proportional to the fourth power of the radius of the blood vessel. Therefore, decreasing the diameter of a blood vessel by ½ would significantly increase the resistance to blood flow, while doubling the length of a blood vessel would have a less pronounced effect on resistance.

Submit
16. The continual movement of fluid through the interstitial spaces produced by capillary filtration serves which of the following functions?

Explanation

The continual movement of fluid through the interstitial spaces helps in the distribution of nutrients and hormones, as it accelerates their transport. It also assists in the transport of insoluble substances that cannot enter the capillaries. Additionally, this movement helps carry toxins and bacteria to the cells of the immune system, aiding in their removal. Moreover, it flushes hormones and wastes from the interstitial spaces. Therefore, all of the given functions are served by the continual movement of fluid through the interstitial spaces.

Submit
17. Edema is favored when

Explanation

Edema is the accumulation of fluid in the tissues, and it can occur when any or all of the mentioned conditions are present. When the plasma concentration of protein is reduced, there is a decrease in the oncotic pressure, which normally helps to draw fluid back into the capillaries. When endothelial permeability increases, it allows more fluid to leak out of the capillaries and into the tissues. Elevated capillary hydrostatic pressure can also push more fluid out of the capillaries. Therefore, all of these factors can contribute to the development of edema.

Submit
18. The earlike extension of the atrium is the

Explanation

The correct answer is "auricle." The earlike extension of the atrium is called the auricle. It is a small, muscular pouch that helps to increase the capacity of the atrium, allowing it to hold more blood. The auricle also helps to direct blood flow into the atrium and prevent backflow.

Submit
19. Cardiac output is increased by

Explanation

The correct answer is "all of the above" because sympathetic stimulation increases the heart rate and contractility, leading to an increase in stroke volume and cardiac output. Increased end-diastolic volume, also known as preload, stretches the myocardium and allows for a greater force of contraction, resulting in an increase in stroke volume and cardiac output. Thus, all three factors mentioned in the options contribute to an increase in cardiac output.

Submit
20. The function of the atrium is to

Explanation

The atrium has two main functions: to collect blood and to pump blood to the ventricle. It receives blood from the veins and acts as a holding chamber, allowing blood to flow into the ventricle when it contracts. Therefore, the correct answer is that the atrium collects blood and pumps it to the ventricle.

Submit
21. Use Figure 18-1 to answer the following questions: 34) Identify the structure labeled "19."

Explanation

The structure labeled "19" in Figure 18-1 is the pulmonary semilunar valves.

Submit
22. Which of the following is greater during left ventricular systole?

Explanation

During left ventricular systole, the ventricle contracts to pump blood out into the aorta. This contraction generates a peak pressure within the ventricle, known as the peak ventricular pressure. This pressure is greater than the peak pressure in the aorta because the ventricle needs to overcome the resistance offered by the aorta to push blood out into the systemic circulation. Therefore, the peak pressure in the ventricle is greater during left ventricular systole.

Submit
23. The following are structural components of the conducting system of the heart. 1. Purkinje fibers 2. AV bundle 3. AV node 4. SA node 5. bundle branches The sequence in which excitation would move through this system is

Explanation

The correct sequence in which excitation would move through the conducting system of the heart is 4, 3, 2, 5, 1. This is because the SA node, located in the right atrium, initiates the electrical impulse that starts each heartbeat. The impulse then travels to the AV node, located in the atrial septum, which delays the impulse to allow for atrial contraction before passing it on to the AV bundle. The AV bundle then divides into the bundle branches, which conduct the impulse towards the Purkinje fibers. Finally, the Purkinje fibers distribute the impulse throughout the ventricles, causing them to contract.

Submit
24. During exercise

Explanation

During exercise, the body requires more oxygen and nutrients to be delivered to the active skeletal muscles. Vasodilation occurs at the active skeletal muscles, which means that the blood vessels in these muscles widen, allowing for increased blood flow and delivery of oxygen and nutrients. This increased blood flow also leads to an increase in venous return, which is the amount of blood returning to the heart. As a result, both cardiac output (the amount of blood pumped by the heart per minute) and stroke volume (the amount of blood pumped by the heart per beat) increase. Therefore, all of the above statements are correct.

Submit
25. After losing 25 percent of blood volume in a motorcycle accident, which of the following compensatory responses would occur?

Explanation

After losing 25 percent of blood volume in a motorcycle accident, the body would undergo compensatory responses to maintain blood pressure and perfusion. Increased heart rate would occur to pump the remaining blood more rapidly. Increase of contractility would help the heart to pump blood more forcefully. Vasoconstriction of the body wall would occur to redirect blood flow to vital organs. Venoconstriction of skin vessels would reduce blood flow to the skin and help conserve blood volume. Therefore, all of the above compensatory responses would occur.

Submit
26. Turbulent blood flow occurs

Explanation

Turbulent blood flow can occur due to irregularities in the vessel wall, high flow rates, and sudden changes in vessel diameter. Irregularities in the vessel wall can disrupt the smooth flow of blood, causing turbulence. High flow rates can also disrupt the laminar flow of blood, leading to turbulence. Additionally, sudden changes in vessel diameter can create disturbances in blood flow, resulting in turbulence. Therefore, all of the above options can contribute to the occurrence of turbulent blood flow.

Submit
27. Materials can move across capillary walls by

Explanation

Materials can move across capillary walls by diffusion, filtration, and reabsorption. Diffusion refers to the movement of molecules from an area of higher concentration to an area of lower concentration. Filtration occurs when fluid and solutes are forced through a membrane by hydrostatic pressure. Reabsorption is the process by which water and solutes are reabsorbed back into the bloodstream from the filtrate. Therefore, all of the above options are correct explanations for the movement of materials across capillary walls.

Submit
28. Pacemaker cells isolated from the SA node generate action potentials at ________ beats per minute.

Explanation

Pacemaker cells isolated from the SA node generate action potentials at a rate of 80-100 beats per minute. These cells are responsible for initiating the electrical signals that regulate the heartbeat. The SA node, located in the right atrium of the heart, acts as the natural pacemaker and sets the rhythm for the rest of the heart. A normal resting heart rate falls within the range of 60-100 beats per minute, with the SA node firing at a rate of 60-100 times per minute. Therefore, the correct answer is 80-100 beats per minute.

Submit
29. ________ is to slow heart rate as ________ is to fast heart rate.

Explanation

Bradycardia refers to a slow heart rate, while tachycardia refers to a fast heart rate. This means that the correct answer is "Bradycardia; tachycardia" as it correctly pairs the terms that represent slow and fast heart rates respectively.

Submit
30. Exchange between a blood vessel and the cells that surround it can occur only in

Explanation

Capillaries are the smallest blood vessels in the body and have thin walls that allow for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding cells. Arteries, arterioles, veins, and venules do not have the same level of permeability as capillaries, and therefore, exchange between blood vessels and surrounding cells primarily occurs in capillaries.

Submit
31. To defend blood volume against dehydration, the body

Explanation

The body defends blood volume against dehydration by implementing multiple mechanisms. It accelerates reabsorption of water at the kidneys, which helps retain water in the body. It also experiences a recall of interstitial fluids, which are the fluids surrounding the cells, to maintain blood volume. Additionally, there is an increase in the blood colloidal osmotic pressure, which helps to retain water in the bloodstream. Lastly, increasing water intake is another way the body defends blood volume against dehydration. Therefore, all of the above options are correct explanations for how the body defends blood volume against dehydration.

Submit
32. The right ventricle pumps blood to the

Explanation

The right ventricle pumps blood to both the right and left lungs. This is because the right ventricle receives deoxygenated blood from the right atrium and pumps it to the lungs through the pulmonary artery. In the lungs, the blood picks up oxygen and gets rid of carbon dioxide before returning to the heart. Therefore, the right ventricle is responsible for pumping blood to both lungs.

Submit
33. The left ventricle pumps blood to the

Explanation

The left ventricle is responsible for pumping oxygenated blood from the heart to the rest of the body through the aorta, the largest artery in the body. The aorta carries the oxygenated blood to all the organs and tissues, ensuring that they receive the necessary oxygen and nutrients for proper functioning.

Submit
34. The pulmonary arteries carry blood to the

Explanation

The correct answer is "lungs" because the pulmonary arteries are responsible for carrying deoxygenated blood from the heart to the lungs, where it can receive oxygen and get rid of carbon dioxide. This oxygenated blood is then returned to the heart to be pumped to the rest of the body.

Submit
35. The pulmonary veins carry blood to the

Explanation

The pulmonary veins carry blood to the heart. This is because the pulmonary veins are responsible for transporting oxygenated blood from the lungs back to the heart so that it can be pumped to the rest of the body. The heart then distributes this oxygenated blood to the various organs and tissues, allowing them to receive the necessary oxygen and nutrients for proper functioning.

Submit
36. Use Figure 18-1 to answer the following questions: Identify the structure labeled "6."

Explanation

The structure labeled "6." in Figure 18-1 is the cusp of the tricuspid valve.

Submit
37. The bicuspid or mitral valve is located

Explanation

The bicuspid or mitral valve is located between the left atrium and left ventricle. This valve prevents the backflow of blood from the left ventricle to the left atrium during the contraction of the heart. It consists of two leaflets or cusps, which open and close to regulate the flow of blood. The location of the bicuspid valve between the left atrium and left ventricle ensures that oxygenated blood is pumped out of the left ventricle and into the systemic circulation, while preventing any backflow into the atrium.

Submit
38. Most of the middle layer in the heart wall is composed of

Explanation

The correct answer is cardiac muscle cells. The middle layer of the heart wall, known as the myocardium, is primarily composed of cardiac muscle cells. These cells are specialized for contraction and play a crucial role in pumping blood throughout the body. Unlike other types of muscle cells, such as smooth muscle cells, cardiac muscle cells have distinct striations and are interconnected by intercalated discs, allowing for coordinated contractions. Therefore, cardiac muscle cells are the main component of the middle layer of the heart wall.

Submit
39. As a result of the long refractory period in the cardiac action potential, cardiac muscle cannot exhibit

Explanation

The long refractory period in the cardiac action potential refers to the period of time after a cardiac muscle cell has depolarized and cannot be stimulated again. This prevents the muscle from entering a state of tetany, which is a sustained and continuous contraction of the muscle. Tetany occurs when the muscle is repeatedly stimulated before it has a chance to fully relax. Therefore, due to the long refractory period, cardiac muscle cannot exhibit tetany.

Submit
40. There are ________ pulmonary veins.

Explanation

There are four pulmonary veins.

Submit
41. In response to hemorrhage, there is

Explanation

In response to hemorrhage, the body undergoes several physiological changes to compensate for the loss of blood. Peripheral vasoconstriction occurs to redirect blood flow to vital organs. There is also increased sympathetic stimulation of the heart, which leads to an increased heart rate and cardiac output. Additionally, the body mobilizes the venous reserve, releasing stored blood from the veins into circulation. Therefore, all of the given options are correct as they describe the various responses to hemorrhage.

Submit
42. Which of the following would be greater?

Explanation

The end-diastolic volume refers to the amount of blood in the ventricles at the end of diastole, which is the relaxation phase of the cardiac cycle. When the heart rate is higher at 150 beats/minute, the ventricles have less time to fill with blood during diastole, resulting in a smaller end-diastolic volume. Conversely, when the heart rate is lower at 60 beats/minute, the ventricles have more time to fill with blood, leading to a larger end-diastolic volume.

Submit
43. When the left ventricle contracts, the distance from the apex to the base

Explanation

When the left ventricle contracts, the distance from the apex to the base decreases. This is because during contraction, the ventricle pushes the blood out of the heart and into the aorta, which causes the walls of the ventricle to come closer together. As a result, the distance from the apex (the bottom of the heart) to the base (the top of the heart) decreases.

Submit
44. Averaged over a few heartbeats, venous return is ________ cardiac output.

Explanation

The statement suggests that venous return, when averaged over a few heartbeats, is equal to cardiac output. This means that the amount of blood returning to the heart through the veins is the same as the amount of blood being pumped out of the heart.

Submit
45. Blood pressure increases with all of the following, except increased

Explanation

Blood pressure is primarily regulated by two factors: cardiac output and peripheral resistance. When cardiac output increases, the heart pumps more blood into the arteries, leading to an increase in blood pressure. Similarly, when peripheral resistance increases, the blood vessels constrict, causing an increase in blood pressure. Additionally, an increase in blood volume can also contribute to elevated blood pressure. However, parasympathetic innervation, which is responsible for regulating the body's rest and digest functions, does not directly affect blood pressure. Therefore, the correct answer is parasympathetic innervation.

Submit
46. Which of the following would increase heart rate?

Explanation

All of the options listed would increase heart rate. Increased sympathetic stimulation of the SA node leads to increased heart rate as it increases the firing rate of the SA node, which is responsible for initiating the electrical impulses that regulate the heart's rhythm. Decreased parasympathetic stimulation of nodal fibers also increases heart rate, as the parasympathetic nervous system slows down heart rate. Increased levels of norepinephrine and/or epinephrine, which are released during stress or exercise, increase heart rate by binding to receptors in the heart and increasing the strength and frequency of contractions. Faster depolarization of the pacemaker potential also leads to an increased heart rate.

Submit
47. The interventricular sulci and coronary sulcus contain

Explanation

The interventricular sulci and coronary sulcus contain fat, arteries, and veins. The interventricular sulci are grooves on the surface of the heart that separate the left and right ventricles. These sulci contain fat, which helps to protect and cushion the heart. The coronary sulcus is a groove that encircles the heart and contains the coronary arteries and veins, which supply blood to the heart muscle. Therefore, all of the given options, including fat, arteries, and veins, are present in the interventricular sulci and coronary sulcus.

Submit
48. The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the

Explanation

During the ventricular ejection phase of the cardiac cycle, the mitral valve is closed to prevent blood from flowing back into the atrium, while the aortic valve is open to allow blood to be ejected from the left ventricle into the aorta. This phase occurs during ventricular systole, which is the contraction of the ventricles.

Submit
49. The volume of blood ejected from each ventricle during a contraction is called the

Explanation

The volume of blood ejected from each ventricle during a contraction is called the stroke volume. This is the amount of blood that is pumped out of the heart with each heartbeat. It is calculated by subtracting the end-systolic volume (the amount of blood left in the ventricle after contraction) from the end-diastolic volume (the amount of blood in the ventricle before contraction). The stroke volume is an important measure of heart function and can be used to calculate the cardiac output, which is the amount of blood pumped by the heart in one minute.

Submit
50. At a heart rate of 60 beats/minute, a cardiac cycle lasts

Explanation

At a heart rate of 60 beats/minute, each beat takes 1 second to complete a full cardiac cycle. This means that the time taken for one complete cycle of contraction and relaxation of the heart is 1 second.

Submit
51. Acetylcholine slows the heart because it

Explanation

Acetylcholine slows the heart because it opens potassium ion channels in SA node cells and causes the pacemaker potential to depolarize more slowly. This allows more time for the heart to relax between contractions and results in a slower heart rate.

Submit
52. Use Figure 18-1 to answer the following questions: Identify the structure labeled "21."

Explanation

The structure labeled "21" in Figure 18-1 is the ligamentum arteriosum.

Submit
53. The term used to describe fluid collecting in the pericardial cavity that restricts the movement of the heart is known as

Explanation

Cardiac tamponade refers to the accumulation of fluid in the pericardial cavity, which is the space between the heart and the pericardium (the sac surrounding the heart). This fluid buildup puts pressure on the heart, restricting its movement and affecting its ability to pump blood effectively. It can be a life-threatening condition requiring immediate medical intervention. Mitral valve prolapse, pleural effusion, cardiomyopathy, and pericarditis are all different conditions that do not specifically involve fluid accumulation in the pericardial cavity.

Submit
54. The heart beats approximately ________ times each day.

Explanation

The correct answer is 100,000. The heart is responsible for pumping blood throughout the body, and it beats around 100,000 times each day. This continuous pumping ensures that oxygen and nutrients are delivered to all the cells in the body and waste products are removed. The heart's consistent beating is essential for maintaining overall health and proper functioning of the body.

Submit
55. As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk.

Explanation

As blood leaves the right ventricle, it passes through the pulmonary valve. The pulmonary valve is located between the right ventricle and the pulmonary trunk. Its main function is to prevent the backflow of blood from the pulmonary trunk into the right ventricle. This allows the blood to flow in one direction, from the heart to the lungs, where it can be oxygenated.

Submit
56. The difference between the systolic and diastolic pressures is called the ________ pressure.

Explanation

The difference between the systolic and diastolic pressures is called the pulse pressure. This is because the pulse pressure represents the force generated by the contraction of the heart during systole and the relaxation of the heart during diastole. It is an important measure of cardiovascular health and can provide information about the elasticity of blood vessels and the overall functioning of the heart.

Submit
57. Activation of which kind of receptor causes heart rate to increase?

Explanation

Activation of beta-one receptors causes heart rate to increase. Beta-one receptors are found in the heart and when they are stimulated, they increase the heart rate. This is because beta-one receptors are responsible for the release of adrenaline, which leads to an increase in heart rate and contractility.

Submit
58. Use Figure 18-1 to answer the following questions: Which chamber receives oxygenated blood from the pulmonary circuit?

Explanation

Chamber 16 receives oxygenated blood from the pulmonary circuit.

Submit
59. Rupture of the papillary muscles in the left ventricle may result in

Explanation

The rupture of the papillary muscles in the left ventricle can lead to several complications, including mitral regurgitation, mitral valve prolapse, and bicuspid regurgitation. This is because the papillary muscles are responsible for anchoring the mitral and bicuspid valves, and their rupture can cause the valves to malfunction. Therefore, all of the options provided can be potential consequences of papillary muscle rupture in the left ventricle.

Submit
60. In which of the following would the resistance be greater?

Explanation

The resistance would be greater in a vessel 10 microns in diameter compared to a vessel 1 mm in diameter. This is because resistance is inversely proportional to the cross-sectional area of the vessel. A smaller diameter vessel has a smaller cross-sectional area, resulting in higher resistance to the flow of fluid or electricity. Therefore, the vessel with a diameter of 10 microns would have a greater resistance than the vessel with a diameter of 1 mm.

Submit
61. Use Figure 18-2 to answer the following question: What occurs at the circled label "5" on the graph?

Explanation

At the circled label "5" on the graph, the occurrence is peak systolic pressure. This means that it represents the highest pressure in the arteries during systole, which is the phase of the cardiac cycle when the heart contracts and pumps blood into the arteries. The peak systolic pressure indicates the maximum force exerted by the heart to push blood out into the circulatory system.

Submit
62. Which of the following descriptions matches the term near the left fifth intercostal space?

Explanation

The term "near the left fifth intercostal space" refers to a specific location on the chest. The apex of the heart is located in this region, making it the correct answer. The pericardial cavity refers to the space surrounding the heart, the visceral pericardium is the inner layer of the pericardium, the aorta is a major blood vessel that carries oxygenated blood from the heart, and the right atrium is one of the chambers of the heart. However, none of these descriptions specifically match the location near the left fifth intercostal space.

Submit
63. Intercalated discs serve to transfer ________ from cell to cell.

Explanation

Intercalated discs are specialized structures found in cardiac muscle cells. They contain gap junctions, which allow for the transfer of ionic currents and action potentials from cell to cell. These electrical signals are essential for coordinating the contraction of the heart muscle. Therefore, intercalated discs play a crucial role in transferring both ionic currents and action potentials, as well as facilitating the force of contraction in cardiac muscle cells. Hence, the correct answer is "all of the above".

Submit
64. The right atrium receives blood from the

Explanation

The right atrium receives blood from all of the above sources, including the coronary sinus, superior vena cava, and inferior vena cava. The coronary sinus drains deoxygenated blood from the heart muscle, while the superior vena cava brings deoxygenated blood from the upper body, and the inferior vena cava brings deoxygenated blood from the lower body.

Submit
65. The wall of the left ventricle is thicker than the right because

Explanation

The wall of the left ventricle is thicker than the right because the left ventricle does more work than the right ventricle. This is because the left ventricle pumps blood to the entire body, while the right ventricle only pumps blood to the lungs. Additionally, the left ventricle pumps against greater resistance than the right ventricle, as the systemic circulation has a higher resistance compared to the pulmonary circulation. Lastly, the left ventricle produces a higher pressure than the right ventricle to overcome the greater resistance and pump blood effectively throughout the body.

Submit
66. Total peripheral resistance is related to all of the following, except the

Explanation

Total peripheral resistance refers to the resistance encountered by blood flow in the systemic circulation. It is influenced by various factors, including blood vessel diameter, flow characteristics, and blood viscosity. The length of a blood vessel also affects resistance, as longer vessels offer more resistance. However, the osmolarity of interstitial fluids does not directly impact total peripheral resistance. Osmolarity refers to the concentration of solutes in a solution, and while it may affect fluid movement between the vascular and interstitial spaces, it does not directly influence the resistance encountered by blood flow in the systemic circulation.

Submit
67. If the pacemaker cells in the SA node become more permeable to potassium ions, the

Explanation

If the pacemaker cells in the SA node become more permeable to potassium ions, it means that more potassium ions will be able to flow out of the cells. This will cause the cells to hyperpolarize, meaning that the membrane potential will become more negative. Hyperpolarization of the membrane makes it more difficult for the cells to reach the threshold for firing an action potential, thus decreasing the heart rate. Therefore, the correct answer is that both the heart rate will decrease and the membrane will hyperpolarize.

Submit
68. Venoconstriction ________ the amount of blood within the venous system, which ________ the volume in the arterial and capillary systems.

Explanation

Venoconstriction refers to the narrowing of the veins, which reduces the amount of blood within the venous system. This reduction in blood volume in the venous system leads to an increase in blood volume in the arterial and capillary systems. Therefore, the correct answer is "reduces; increases".

Submit
69. The AV node delivers the stimulus to the AV bundle, located within the interventricular septum.

Explanation

The AV node does deliver the stimulus to the AV bundle, which is indeed located within the interventricular septum. Therefore, both parts of the statement are true.

Submit
70. Drugs that block the beta-one adrenergic receptors will

Explanation

Blocking the beta-one adrenergic receptors will decrease heart rate because these receptors are responsible for the stimulation of the heart. When they are blocked, the sympathetic nervous system's influence on the heart is reduced, leading to a decrease in heart rate.

Submit
71. Blood flowing into the heart from the venae cavae flows next through the ________ valve.

Explanation

The blood flowing into the heart from the venae cavae flows next through the tricuspid valve.

Submit
72. During the cardiac cycle, the

Explanation

During the cardiac cycle, the QRS complex of the ECG precedes the increase in ventricular pressure. This is because the QRS complex represents ventricular depolarization, which occurs before ventricular contraction and the subsequent increase in ventricular pressure. Additionally, the first heart sound coincides with the QRS complex of the ECG. This is because the first heart sound, also known as S1, is produced by the closure of the atrioventricular valves at the beginning of ventricular systole, which aligns with the QRS complex on the ECG.

Submit
73. Abnormally slow depolarization of the ventricles would most change the shape of the ________ in an ECG tracing.

Explanation

Abnormally slow depolarization of the ventricles would most change the shape of the QRS complex in an ECG tracing. The QRS complex represents the depolarization of the ventricles, so if this depolarization is abnormally slow, it would result in a prolonged or widened QRS complex. This change in shape indicates a delay in the electrical conduction through the ventricles, which could be caused by various conditions such as bundle branch block or ventricular tachycardia.

Submit
74. The first heart sound is heard when the

Explanation

The first heart sound, also known as S1, is caused by the closure of the AV valves. These valves, which include the tricuspid valve on the right side of the heart and the mitral valve on the left side, close to prevent the backflow of blood from the ventricles to the atria during ventricular contraction. This closure produces a sound that can be heard as the "lub" sound of the heartbeat. Therefore, the correct answer is AV valves close.

Submit
75. Blood pressure is highest here.

Explanation

Arteries are blood vessels that carry oxygenated blood away from the heart to the rest of the body. They have thick and elastic walls that allow them to withstand the high pressure generated by the pumping action of the heart. Arteries have the highest blood pressure among the given options because they receive blood directly from the heart and are responsible for distributing it throughout the body.

Submit
76. Use Figure 18-1 to answer the following questions: Identify the structure labeled "8."

Explanation

The structure labeled "8." in Figure 18-1 is the papillary muscles.

Submit
77. ________ is to contraction as ________ is to relaxation.

Explanation

The correct answer is Systole; diastole or Ejection; filling. In the context of the question, "contraction" is the opposite of "relaxation". Systole refers to the contraction phase of the cardiac cycle, while diastole refers to the relaxation phase. Similarly, ejection refers to the contraction of the ventricles and the expulsion of blood, while filling refers to the relaxation of the heart chambers and the filling of blood. Both pairs of terms represent the opposite actions of contraction and relaxation.

Submit
78. During ventricular systole, the

Explanation

During ventricular systole, the AV valves are closed. This is because ventricular systole refers to the contraction of the ventricles, which causes an increase in pressure within the ventricles. As the ventricles contract, the AV valves close to prevent the backflow of blood into the atria. This closure of the AV valves ensures that blood is forced into the arteries and prevents any regurgitation of blood into the atria. Therefore, during ventricular systole, the AV valves being closed is the correct answer.

Submit
79. In which of the following would the blood flow be highest?

Explanation

In this question, the blood flow is directly related to the cross-sectional area of the vessel. The larger the diameter of the vessel, the greater the cross-sectional area, and therefore, the higher the blood flow. Additionally, the length of the vessel does not affect the blood flow. Therefore, the vessel with a diameter of 1.0 cm will have the highest blood flow, regardless of its length.

Submit
80. If blood pressure doubled, the blood flow through a vessel would be

Explanation

If blood pressure doubled, it means that there is an increase in the force exerted by the blood against the walls of the vessel. This increased pressure would result in an increase in the blood flow through the vessel. Therefore, the correct answer is that the blood flow would be doubled.

Submit
81. Blood pressure is lowest in the

Explanation

Veins have the lowest blood pressure compared to arteries, arterioles, capillaries, and venules. This is because veins carry deoxygenated blood back to the heart, and the pressure exerted by the heart has decreased significantly by the time the blood reaches the veins. Additionally, veins have thinner walls and less smooth muscle compared to arteries, which also contributes to their lower blood pressure.

Submit
82. The heart pumps approximately ________ milliliters of blood each minute.

Explanation

The heart pumps approximately 6,000 milliliters of blood each minute. This is because the heart is responsible for circulating blood throughout the body, supplying oxygen and nutrients to the cells. The average adult has a blood volume of about 5 liters, and the heart completes one full cycle of pumping all the blood in the body in about one minute. Therefore, the heart pumps approximately 6,000 milliliters (or 6 liters) of blood each minute to maintain proper circulation.

Submit
83. The blood colloid osmotic pressure mostly depends on the

Explanation

The blood colloid osmotic pressure is mainly determined by the concentration of plasma proteins. This pressure is essential for maintaining fluid balance in the blood vessels. Plasma proteins, such as albumin, exert an osmotic force that helps to draw fluid back into the blood vessels from the surrounding tissues. When the concentration of plasma proteins is low, as in conditions like liver disease or malnutrition, the blood colloid osmotic pressure decreases, leading to fluid accumulation in the tissues and causing edema. Therefore, the concentration of plasma proteins is crucial for maintaining the blood colloid osmotic pressure.

Submit
84. The visceral pericardium is the same as the

Explanation

The visceral pericardium refers to the innermost layer of the pericardium, which is the protective sac surrounding the heart. It is also known as the epicardium. The epicardium is a thin layer of connective tissue that covers the outer surface of the heart and helps to protect and lubricate it. It is responsible for providing a smooth surface for the heart to beat against and helps to reduce friction between the heart and surrounding structures. Therefore, the correct answer is epicardium.

Submit
85. Depolarization of the ventricles is represented on an electrocardiogram by the

Explanation

The QRS complex represents the depolarization of the ventricles on an electrocardiogram. This complex is a series of waves that indicate the contraction of the ventricles, which is the main pumping action of the heart. The P wave represents the depolarization of the atria, while the T wave represents the repolarization of the ventricles. The S wave is not directly related to ventricular depolarization. The PR complex is not a recognized term in electrocardiography.

Submit
86. Compared to the right ventricle, the left ventricle has all the following characteristics, except that it

Explanation

The left ventricle has a thicker wall, is round in cross section, contracts harder, and produces about four to six times more pressure when it contracts compared to the right ventricle. However, it does not pump a greater volume.

Submit
87. The following is a list of vessels and structures that are associated with the heart.   1. right atrium 2. left atrium 3. right ventricle 4. left ventricle 5. venae cavae 6. aorta 7. pulmonary trunk 8. pulmonary veins   What is the correct order for the flow of blood entering from the systemic circulation?

Explanation

not-available-via-ai

Submit
88. The mitral valve closes

Explanation

The correct answer is "all of the above." The mitral valve closes when left ventricular pressure exceeds left atrial pressure, which typically occurs at the beginning of ventricular systole. Additionally, the mitral valve and the tricuspid valve usually close at the same time, as they are both atrioventricular valves.

Submit
89. Each of the following will cause an increase in blood pressure, except

Explanation

Increased levels of ANP (atrial natriuretic peptide) will not cause an increase in blood pressure. ANP is a hormone released by the heart in response to high blood volume and pressure. It acts to decrease blood pressure by promoting vasodilation (widening of blood vessels) and increasing the excretion of sodium and water in the urine, which reduces blood volume. Therefore, increased levels of ANP will actually lead to a decrease in blood pressure, making it the exception among the given options.

Submit
90. Which of the following changes doesn't occur during exercise compared to rest?

Explanation

During exercise, the body requires more oxygen and nutrients, which leads to an increase in cardiac output and heart blood flow. This is necessary to meet the increased demand of the working muscles. However, skin blood flow decreases during exercise as the body directs more blood towards the muscles and vital organs, prioritizing their needs over the skin. This helps regulate body temperature and prevent overheating during physical activity. The decrease in abdominal viscera and kidney blood flow is not observed during exercise, as these organs still require a sufficient blood supply to function properly.

Submit
91. The ________ deliver(s) blood to the myocardium.

Explanation

The right coronary artery and left coronary artery are responsible for delivering blood to the myocardium, which is the muscular tissue of the heart. These arteries supply oxygen and nutrients to the heart muscle, ensuring its proper functioning.

Submit
92. The ________ valve prevents backward flow into the left atrium.

Explanation

The bicuspid valve, also known as the mitral valve, is located between the left atrium and the left ventricle of the heart. Its main function is to prevent the backward flow of blood from the left ventricle into the left atrium during ventricular contraction.

Submit
93. If a person has a blood pressure of 120/90, his mean arterial pressure would be ________ mm Hg.

Explanation

The mean arterial pressure (MAP) is calculated by adding one-third of the difference between the systolic and diastolic blood pressures to the diastolic blood pressure. In this case, the systolic blood pressure is 120 and the diastolic blood pressure is 90. The difference between them is 30, and one-third of that is 10. Adding 10 to the diastolic pressure of 90 gives us a mean arterial pressure of 100 mm Hg.

Submit
94. In comparing a trained athlete to a non-athlete, which of these comparisons is false?

Explanation

The comparison that is false is "Both hearts weigh about the same." This is incorrect because a trained athlete's heart is larger and stronger compared to a non-athlete's heart. Regular exercise causes the heart to adapt and become more efficient, resulting in an increase in heart size and stroke volume. Therefore, the athlete's heart would weigh more than a non-athlete's heart.

Submit
95. The cusps (leaflets) of atrioventricular valves attach directly to

Explanation

The cusps (leaflets) of atrioventricular valves attach directly to chordae tendineae. Chordae tendineae are strong, fibrous cords that connect the cusps of the atrioventricular valves to the papillary muscles in the ventricles. This connection helps to prevent the valves from inverting or prolapsing during ventricular contraction, ensuring proper blood flow through the heart.

Submit
96. Complications related to arteriosclerosis account for roughly ________ percent of deaths in the United States.

Explanation

Arteriosclerosis is a condition characterized by the hardening and narrowing of arteries, which can lead to various complications such as heart attacks and strokes. The given answer of 50 percent suggests that half of the deaths in the United States are caused by complications related to arteriosclerosis. This indicates the significant impact of this condition on mortality rates in the country.

Submit
97. The normal pacemaker of the heart is located in the

Explanation

The sinoatrial node is the natural pacemaker of the heart, responsible for initiating the electrical signals that regulate the heart's rhythm. Located in the upper right atrium, it generates electrical impulses that spread through the atria, causing them to contract and pump blood into the ventricles. From there, the impulses travel to the atrioventricular node and then to the Purkinje fibers, which stimulate the contraction of the ventricles. However, the primary pacemaker is the sinoatrial node, making it the correct answer.

Submit
98. When renin is released from the kidney

Explanation

When renin is released from the kidney, it initiates a cascade of reactions that ultimately lead to the activation of angiotensin I. Renin acts on angiotensinogen, a precursor protein, to convert it into angiotensin I. Angiotensin I is then further converted to angiotensin II through the action of an enzyme called angiotensin-converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor, meaning it causes the blood vessels to constrict, leading to an increase in blood pressure. Therefore, the correct answer is that angiotensin I is activated.

Submit
99. In cardiac muscle, the fast depolarization phase of the action potential is the result of

Explanation

The fast depolarization phase of the action potential in cardiac muscle is caused by an increased membrane permeability to sodium ions. This allows sodium ions to rapidly enter the cell, leading to depolarization and the generation of an action potential. This increased permeability is due to the opening of voltage-gated sodium channels in response to a stimulus. The influx of sodium ions triggers the opening of voltage-gated calcium channels, which then allows calcium ions to enter the cell and initiate muscle contraction. Therefore, the correct answer is increased membrane permeability to sodium ions.

Submit
100. Blood leaves the right ventricle by passing through the

Explanation

The pulmonary valve is the correct answer because it is responsible for allowing blood to leave the right ventricle and enter the pulmonary artery, which carries deoxygenated blood to the lungs for oxygenation. The other options mentioned are incorrect as they are not directly involved in the passage of blood from the right ventricle.

Submit
101. Analysis of the electrocardiogram can reveal all of the following, except the

Explanation

The electrocardiogram (ECG) is a diagnostic tool used to measure the electrical activity of the heart. It provides valuable information about the heart's rhythm, the condition of the conducting system, the effects of drugs and poisons, and the duration of the ventricular action potential. However, it does not directly provide information about the stroke volume, which is the amount of blood pumped out of the heart with each contraction. Stroke volume is typically measured using other techniques such as echocardiography or cardiac catheterization.

Submit
102. Depolarization of the atria corresponds to the ECG's

Explanation

The depolarization of the atria refers to the electrical activation of the atrial muscle cells, which leads to contraction. This electrical activity is represented on an ECG as the P wave. The P wave represents the depolarization of the atria, while the other options (QRS complex, QT interval, T wave, and S-T segment) represent different phases or components of the cardiac cycle that are not specifically related to the depolarization of the atria.

Submit
103. Blood is supplied to the myocardium by

Explanation

The correct answer is the coronary arteries. The myocardium, which is the muscular tissue of the heart, receives blood supply from the coronary arteries. These arteries branch off from the aorta and provide oxygenated blood to the heart muscle. The coronary arteries ensure that the myocardium receives the necessary nutrients and oxygen to function properly. The other options, such as the coronary sinus or contact with blood in the pumping chambers, are not correct as they do not supply blood to the myocardium.

Submit
104. The P wave of the electrocardiogram is a signal from

Explanation

The P wave of the electrocardiogram represents the depolarization of the atria. Depolarization refers to the electrical activation of the heart muscle cells, causing them to contract. In this case, the P wave specifically represents the depolarization of the atria, which are the upper chambers of the heart. This electrical signal initiates the contraction of the atria, allowing them to pump blood into the ventricles. Therefore, the correct answer is depolarization of the atria.

Submit
105. Contractions of the papillary muscles

Explanation

The contractions of the papillary muscles prevent the atrioventricular valves from reversing into the atria. These muscles are located in the ventricles of the heart and are connected to the atrioventricular valves by chordae tendineae. When the ventricles contract, the papillary muscles also contract, pulling on the chordae tendineae and preventing the valves from flipping back into the atria. This ensures that blood flows in one direction, from the atria to the ventricles, and prevents any backflow of blood into the atria.

Submit
106. As blood travels from arteries to veins,

Explanation

As blood travels from arteries to veins, the pressure drops. This is because the arteries carry oxygenated blood from the heart to the rest of the body at high pressure, while the veins carry deoxygenated blood back to the heart at a lower pressure. The pressure drop occurs due to the resistance encountered by the blood as it flows through the smaller blood vessels and capillaries. This decrease in pressure allows the blood to flow more slowly and efficiently through the veins, facilitating the exchange of nutrients and waste products in the tissues.

Submit
107. Which of the following factors will increase the net filtration pressure to move fluid out of capillaries?

Explanation

All of the factors mentioned will increase the net filtration pressure to move fluid out of capillaries. Decreased plasma albumen reduces the colloid osmotic pressure, allowing more fluid to move out of the capillaries. Increased blood hydrostatic pressure increases the pressure gradient, pushing more fluid out of the capillaries. Decreased tissue hydrostatic pressure reduces the opposing pressure, facilitating the movement of fluid out of the capillaries. Therefore, all of these factors contribute to an increase in net filtration pressure.

Submit
108. The coronary sulcus is a groove that

Explanation

The coronary sulcus is a groove that marks the border between the atria and ventricles. This groove is located on the surface of the heart and helps to separate the upper chambers (atria) from the lower chambers (ventricles). It serves as a landmark for identifying the different regions of the heart and is important for understanding the anatomy and function of the heart.

Submit
109. Cardiac output can be increased by all of the following except one. Choose the exception.

Explanation

Decreasing ejection fraction refers to the percentage of blood pumped out of the heart with each contraction. A lower ejection fraction indicates that the heart is not effectively pumping blood, resulting in a decreased cardiac output. In contrast, increasing stroke volume, ejection fraction, and heart rate all contribute to an increased cardiac output. Therefore, decreasing ejection fraction is the exception as it does not increase cardiac output.

Submit
110. David suffers from a prolapsed mitral valve. This condition would cause

Explanation

A prolapsed mitral valve refers to the improper closure of the valve between the left atrium and the left ventricle of the heart. This condition would cause regurgitation, which means that blood would flow backward into the left atrium instead of moving forward into the aorta. As a result, the left ventricle would need to exert increased effort to pump blood out of the heart and into the circulation. Therefore, the correct answer is increased effort by the left ventricle and regurgitation.

Submit
111. Each of the following will lead to a decrease in blood pressure, except

Explanation

The release of renin is not associated with a decrease in blood pressure. Renin is an enzyme that is released by the kidneys when blood pressure is low. It acts on a protein called angiotensinogen to produce angiotensin I, which is then converted to angiotensin II. Angiotensin II is a potent vasoconstrictor, meaning it causes blood vessels to constrict, leading to an increase in blood pressure. Therefore, the release of renin actually leads to an increase in blood pressure, making it the exception in this list.

Submit
112. Blood returning to the heart from the systemic circuit first enters the

Explanation

Blood returning to the heart from the systemic circuit first enters the right atrium. This is because after oxygenated blood is delivered to the body through the systemic arteries, it returns to the heart through the systemic veins. The superior and inferior vena cava, which are large veins, carry deoxygenated blood from the body back to the heart. They both empty into the right atrium, where blood is then pumped into the right ventricle and eventually sent to the lungs for oxygenation. Therefore, the correct answer is right atrium.

Submit
113. Blood returning to the heart from the pulmonary circuit first enters the

Explanation

Blood returning to the heart from the pulmonary circuit first enters the left atrium. This is because after oxygenation in the lungs, the oxygen-rich blood is transported back to the heart through the pulmonary veins, which empty into the left atrium. From the left atrium, the blood then passes through the mitral valve into the left ventricle before being pumped out to the rest of the body.

Submit
114. Which of these would cause stroke volume to increase?

Explanation

When venous return is increased, more blood is returned to the heart, which leads to an increase in stroke volume. This is because an increased venous return results in a higher preload, which stretches the cardiac muscle fibers and allows for a more forceful contraction, thus increasing stroke volume. On the other hand, when diastolic blood pressure is decreased, there is less resistance against which the heart has to pump, allowing for an easier ejection of blood and an increase in stroke volume. Therefore, both an increased venous return and a decreased diastolic blood pressure can independently cause an increase in stroke volume.

Submit
115. The T wave on an ECG tracing represents

Explanation

The T wave on an ECG tracing represents ventricular repolarization. This is the phase of the cardiac cycle where the ventricles are recovering and preparing for the next contraction. As the ventricles repolarize, they relax and reset their electrical state, allowing for proper filling of blood before the next contraction.

Submit
116. The foramen ovale in the fetal heart is located in the  

Explanation

The foramen ovale is a small opening in the interatrial septum, which is the wall that separates the right and left atria of the heart. This opening allows blood to bypass the fetal lungs and flow directly from the right atrium to the left atrium. This is important during fetal development because the lungs are not yet functioning and the oxygenation of blood occurs through the placenta. After birth, the foramen ovale typically closes, redirecting blood flow through the lungs.

Submit
117. The vascular pressure that declines from roughly 35 mm Hg to about 18 mm Hg is the

Explanation

The correct answer is capillary hydrostatic pressure. Capillary hydrostatic pressure refers to the pressure exerted by the fluid within the capillaries of the circulatory system. It is responsible for forcing fluids, such as nutrients and oxygen, out of the capillaries and into the surrounding tissues. The given range of pressure, declining from 35 mm Hg to about 18 mm Hg, aligns with the typical values of capillary hydrostatic pressure.

Submit
118. Stimulation of the aortic baroreceptors results in

Explanation

Stimulation of the aortic baroreceptors triggers a reflex response to decrease blood pressure. This is achieved by increasing the activity of the parasympathetic nervous system, which causes a decrease in heart rate and vasodilation of blood vessels. This response helps to counteract the initial increase in blood pressure. The other options, such as stimulation of the cardioacceleratory center, increased sympathetic stimulation of the heart, stimulation of the vasoconstrictive center, and increased heart rate, would all result in an increase in blood pressure rather than a decrease.

Submit
119. The first blood vessels to branch from the aorta are the ________ arteries.

Explanation

The first blood vessels to branch from the aorta are the coronary arteries. These arteries supply oxygenated blood to the heart muscle itself. They are responsible for delivering the necessary nutrients and oxygen to the heart, allowing it to function properly. Without the coronary arteries, the heart would not receive the blood supply it needs, which could lead to various heart conditions and complications.

Submit
120. ADH and aldosterone secretion are part of the body's long-term compensation for

Explanation

ADH (antidiuretic hormone) and aldosterone are hormones that are released by the body in response to a serious hemorrhage. A serious hemorrhage leads to a significant loss of blood volume, which triggers the release of ADH and aldosterone. ADH helps to retain water in the body by reducing urine production, while aldosterone promotes the reabsorption of sodium and water in the kidneys. Both of these hormones work together to increase blood volume and maintain blood pressure, which is necessary to compensate for the loss of blood during a serious hemorrhage.

Submit
121. Each of the following changes will result in increased blood flow to a tissue, except

Explanation

Increased hematocrit refers to an increase in the proportion of red blood cells in the blood. While this can affect the viscosity of the blood, it does not directly impact blood flow to a tissue. Increased vessel diameter, increased blood pressure, decreased peripheral resistance, and relaxation of precapillary sphincters all contribute to increased blood flow by allowing more blood to reach the tissue.

Submit
122. The main control of peripheral resistance by the vasomotor centers occurs in the

Explanation

The main control of peripheral resistance by the vasomotor centers occurs in the arteriole. Arterioles are small blood vessels that regulate blood flow and control the resistance to blood flow. They have smooth muscle in their walls, which can contract or relax to adjust the diameter of the vessel. By constricting or dilating the arterioles, the vasomotor centers can regulate the resistance to blood flow and control blood pressure. This allows for precise control of blood flow to different tissues and organs based on their metabolic needs.

Submit
123. The cardioacceleratory center activates sympathetic neurons and the cardioinhibitory center controls parasympathetic neurons.

Explanation

The explanation for the correct answer is that the statement is stating two separate facts. The first part of the statement is false because the cardioacceleratory center actually activates sympathetic neurons, not parasympathetic neurons. However, the second part of the statement is true because the cardioinhibitory center does control parasympathetic neurons. Therefore, both parts of the statement are true, but they relate to different aspects of brainstem control of heart rate.

Submit
124. During the T wave of the electrocardiogram, the ventricles are

Explanation

During the T wave of the electrocardiogram, the ventricles are both repolarizing and relaxing. Repolarization refers to the process where the ventricles regain their electrical charge after depolarization, which occurs during the QRS complex. Relaxation, also known as diastole, is the phase when the ventricles are filling with blood and preparing for the next contraction. Therefore, during the T wave, the ventricles are undergoing repolarization and relaxation simultaneously.

Submit
125. The great and middle cardiac veins drain blood into the

Explanation

The great and middle cardiac veins are responsible for draining blood from the heart muscle. This blood is then collected into a large vein called the coronary sinus. The coronary sinus is located in the coronary sulcus, which is a groove that runs along the surface of the heart. From the coronary sinus, the blood is eventually returned to the right atrium of the heart. Therefore, the correct answer is coronary sinus.

Submit
126. Drugs known as calcium channel blockers such as nifedipine can be used to

Explanation

Calcium channel blockers, like nifedipine, work by blocking calcium channels in the heart muscle cells. Calcium is necessary for the contraction of the heart muscle, so by blocking these channels, the entry of calcium into the cells is reduced. This leads to a decrease in the force of cardiac contraction, making the heart pump with less force. Therefore, the correct answer is "decrease the force of cardiac contraction."

Submit
127. Use Figure 18-2 to answer the following question: What occurs at the circled label "4" on the graph?

Explanation

At the circled label "4" on the graph, isovolumetric contraction occurs. This refers to the phase of the cardiac cycle where the ventricles contract, causing an increase in pressure within the ventricles. However, during this phase, the volume of blood in the ventricles remains constant as both the atrioventricular and semilunar valves are closed. This allows for the build-up of pressure necessary to open the semilunar valves and initiate ejection of blood during the next phase of the cardiac cycle.

Submit
128. Which of the following statements is false concerning the movement of fluid between capillaries and interstitial space?

Explanation

The net filtration pressure is usually zero because it is the balance between the forces that promote fluid movement out of the capillaries (blood hydrostatic pressure) and the forces that promote fluid movement back into the capillaries (blood osmotic pressure). When these forces are equal, there is no net movement of fluid.

Submit
129. If the connection between the SA node and AV node becomes blocked,

Explanation

When the connection between the SA node and AV node becomes blocked, it disrupts the normal conduction pathway of electrical signals in the heart. The SA node is responsible for initiating the electrical impulses that regulate the heart's rhythm, and the AV node helps to transmit these impulses to the ventricles. If the connection is blocked, the ventricles will no longer receive the signals to contract at the normal pace set by the SA node. As a result, the ventricles will beat more slowly, leading to a decrease in heart rate.

Submit
130. The long plateau phase of the cardiac muscle action potential is due to

Explanation

During the plateau phase of the cardiac muscle action potential, the calcium channels remain open. This allows calcium ions to continue flowing into the cell, balancing the outward flow of potassium ions. This sustained influx of calcium helps to maintain the depolarization of the cell membrane and prolongs the action potential, leading to a longer contraction of the cardiac muscle.

Submit
131. The first heart sound ("lubb")

Explanation

The first heart sound, known as "lubb," is associated with the closing of the mitral valve. This occurs during ventricular systole when the ventricles contract and the pressure inside them increases. The closure of the mitral valve prevents the backflow of blood from the left ventricle to the left atrium, causing the characteristic sound. The opening of the mitral valve occurs during atrial systole, which is not associated with the first heart sound. The closing of the aortic valve is associated with the second heart sound.

Submit
132. Increased levels of carbon dioxide in the blood will result in decreased

Explanation

Increased levels of carbon dioxide in the blood can trigger the parasympathetic nervous system, leading to parasympathetic stimulation of the heart. This stimulation causes the heart rate to decrease.

Submit
133. Tetanic muscle contractions don't occur in a normal cardiac muscle because

Explanation

Tetanic muscle contractions occur when a muscle is stimulated repeatedly without adequate time for relaxation in between. In a normal cardiac muscle, the refractory period is the time during which the muscle cannot be stimulated again. This refractory period lasts until the muscle relaxes, preventing tetanic contractions from occurring. This is important for the proper functioning of the heart, as it allows for adequate filling and pumping of blood.

Submit
134. Homeostatic mechanisms in response to blood loss include all of the following, except

Explanation

During blood loss, the body activates several homeostatic mechanisms to maintain a stable internal environment. These mechanisms include the uptake of interstitial fluid due to reduced capillary pressure, activation of ADH secretion to conserve water, activation of aldosterone secretion to retain sodium and water, and increased thirst and water intake to restore fluid balance. However, the secretion of erythropoietin (EPO), a hormone that stimulates red blood cell production, is inhibited during blood loss. This is because the body prioritizes conserving fluid rather than producing more red blood cells.

Submit
135. If there is a complete block between the SA node and the AV node, how would the ECG be affected?

Explanation

If there is a complete block between the SA node and the AV node, it means that the electrical signals from the atria cannot reach the ventricles. As a result, the ventricles will not receive the signals to contract and will stop beating. However, the SA node will continue to generate electrical signals, causing the atria to continue contracting and producing P waves on the ECG. Since the ventricles are not contracting, there will be no QRS complexes on the ECG. Therefore, the rate of P waves will be faster than the rate of QRS complexes.

Submit
136. Blood is supplied to the left atrium by the

Explanation

The left coronary artery is responsible for supplying blood to the left atrium. It is one of the main branches of the aorta and plays a crucial role in providing oxygenated blood to the heart muscle. The left coronary artery divides into two main branches, the left anterior descending artery and the left circumflex artery, which supply blood to different areas of the heart. This ensures that the left atrium receives a sufficient blood supply for its proper functioning.

Submit
137. Pacemaker cells in the SA node

Explanation

The correct answer is "generate action potentials that spread to the myocardium." Pacemaker cells in the SA node are responsible for initiating and regulating the heartbeat. They have a unique ability to spontaneously generate action potentials, which then spread to the myocardium (the muscular tissue of the heart) and stimulate contraction. These action potentials are essential for coordinating the rhythmic contractions of the heart and ensuring proper blood flow throughout the body.

Submit
138. The marginal branch and posterior interventricular branch are branches of the

Explanation

The marginal branch and posterior interventricular branch are both branches of the right coronary artery. The right coronary artery is one of the main arteries that supplies blood to the heart muscle. The marginal branch runs along the right border of the heart and supplies blood to the right ventricle. The posterior interventricular branch runs along the back of the heart and supplies blood to the posterior part of the interventricular septum and the posterior walls of the ventricles. Therefore, the correct answer is the right coronary artery.

Submit
139. The circumflex branch and the anterior interventricular artery are branches of the

Explanation

The circumflex branch and the anterior interventricular artery are both branches of the left coronary artery. The left coronary artery is responsible for supplying blood to the left side of the heart, including the left ventricle and left atrium. The circumflex branch wraps around the left side of the heart, while the anterior interventricular artery supplies blood to the front of the heart. Therefore, the left coronary artery is the correct answer as it gives rise to both of these important branches.

Submit
140. Each of the following factors will increase cardiac output, except

Explanation

Increased parasympathetic stimulation will not increase cardiac output. The parasympathetic nervous system is responsible for slowing down the heart rate and reducing the force of contractions. Therefore, increased parasympathetic stimulation would have the opposite effect and decrease cardiac output. On the other hand, increased venous return, sympathetic stimulation, and heart rate will all increase cardiac output by increasing the amount of blood pumped by the heart.

Submit
141. Coronary veins empty into the

Explanation

Coronary veins empty into the right atrium. The coronary veins are responsible for draining deoxygenated blood from the heart muscle. After supplying oxygen and nutrients to the heart muscle, the coronary arteries collect the deoxygenated blood and transport it back to the right atrium through the coronary veins. From the right atrium, the blood will then be pumped into the right ventricle and eventually to the lungs for oxygenation. Therefore, the correct answer is right atrium.

Submit
142. An increase in the rate of action potentials from baroreceptors will lead to

Explanation

An increase in the rate of action potentials from baroreceptors indicates that blood pressure is high. In response, the body initiates a parasympathetic response to decrease heart rate, which helps to lower blood pressure. Therefore, an increase in the rate of action potentials from baroreceptors will lead to both a decrease in heart rate and a decrease in blood pressure.

Submit
143. In cardiac muscle

Explanation

In cardiac muscle, calcium ions enter the cell through slow ion channels. This is important because calcium ions are necessary for the process of contraction in cardiac muscle. When the slow ion channels open, calcium ions flow into the cell, triggering the release of more calcium ions from the sarcoplasmic reticulum. These calcium ions then bind to troponin molecules, allowing the muscle fibers to contract. Therefore, the entry of calcium ions through slow ion channels is crucial for the contraction of cardiac muscle.

Submit
144. The pulmonary semilunar valve prevents backward flow into the

Explanation

The pulmonary semilunar valve is located between the right ventricle and the pulmonary trunk. Its main function is to prevent the backward flow of blood from the pulmonary trunk into the right ventricle. This ensures that oxygenated blood from the lungs is directed towards the systemic circulation through the aorta, rather than returning to the right ventricle. Therefore, the correct answer is right ventricle.

Submit
145. Each of the following factors would increase peripheral resistance, except

Explanation

Vasodilation refers to the widening of blood vessels, which leads to a decrease in peripheral resistance. Increased sympathetic stimulation, elevated levels of epinephrine, irregularities in vessel walls caused by plaques, and elevated hematocrit all contribute to increased peripheral resistance. Therefore, the only factor that would not increase peripheral resistance is vasodilation.

Submit
146. Use Figure 18-2 to answer the following question: What occurs at the area labeled "D" on the graph?

Explanation

not-available-via-ai

Submit
147. If the connection between the vagus nerve and the heart is cut, which of these changes will occur?

Explanation

If the connection between the vagus nerve and the heart is cut, none of the changes mentioned in the options will occur. The vagus nerve is responsible for regulating the parasympathetic control of the heart, which helps to slow down the heart rate. Cutting the connection between the vagus nerve and the heart would result in the loss of parasympathetic control, leading to an increase in heart rate rather than a decrease. Therefore, none of the options provided accurately describe the changes that would occur in this scenario.

Submit
148. Use Figure 18-2 to answer the following question: What occurs at "B" on the graph?

Explanation

At "B" on the graph, the AV valve opens. This can be determined by referring to Figure 18-2, which likely provides a visual representation of the cardiac cycle. The AV valve, also known as the atrioventricular valve, is responsible for allowing blood to flow from the atria to the ventricles of the heart. When the AV valve opens, it allows blood to pass from the atria into the ventricles, facilitating the filling of the ventricles before they contract.

Submit
149. Paul has a horrible chainsaw accident and cuts several major blood vessels in his head and neck. As a result of this injury, you would expect to observe all of the following, except

Explanation

When major blood vessels in the head and neck are cut, the body's natural response is to increase the heart rate, increase cardiac output, increase secretion of renin by the kidneys, and increase total peripheral resistance in order to maintain blood pressure and ensure adequate blood flow to vital organs. However, an increase in cardiac output is not expected because cardiac output is the product of heart rate and stroke volume, and in this scenario, the injury to the blood vessels would likely result in a decrease in stroke volume.

Submit
150. During the isovolumetric contraction phase of ventricular systole, the

Explanation

During the isovolumetric contraction phase of ventricular systole, the atria are contracting and the ventricles are relaxing. This means that the atrioventricular valves (mitral and tricuspid valves) are closed to prevent backflow of blood from the ventricles to the atria. Additionally, the semilunar valves (aortic and pulmonary valves) are also closed to prevent backflow of blood from the great vessels into the ventricles. Therefore, the correct answer is that the atrioventricular valves and semilunar valves are closed during this phase.

Submit
151. Use Figure 18-2 to answer the following question: What occurs at "A" on the graph?

Explanation

At "A" on the graph, the semilunar valve opens.

Submit
152. What effect would compressing the inferior vena cava just below the diaphragm have on cardiac function?

Explanation

Compressing the inferior vena cava just below the diaphragm would impede the return of deoxygenated blood to the heart, leading to a decrease in preload. This decrease in preload would trigger the activation of the sympathetic nervous system, causing sympathetic stimulation of the heart. Sympathetic stimulation increases heart rate, contractility, and cardiac output in order to compensate for the decreased preload. Therefore, the correct answer is that sympathetic stimulation of the heart would increase.

Submit
153. If a patient's tricuspid valve was leaking during systole, what would happen?

Explanation

If a patient's tricuspid valve was leaking during systole, regurgitation into the left atrium would occur. The tricuspid valve is located between the right atrium and right ventricle, so if it is leaking, blood would flow back into the right atrium. However, since the left and right atria are connected, the regurgitated blood from the right atrium can also flow into the left atrium. This would result in regurgitation into the left atrium.

Submit
154. Blood flow to a tissue will increase if the

Explanation

When arterioles dilate, the diameter of the blood vessels increases, allowing more blood to flow through them. This increase in blood flow leads to an increase in oxygen delivery to the tissue and a decrease in the level of carbon dioxide, as well as improved waste removal. Therefore, arterioles dilating would result in an overall increase in blood flow to the tissue.

Submit
View My Results

Quiz Review Timeline (Updated): Mar 22, 2023 +

Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.

  • Current Version
  • Mar 22, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Jun 12, 2013
    Quiz Created by
    Seres21e
Cancel
  • All
    All (154)
  • Unanswered
    Unanswered ()
  • Answered
    Answered ()
Which of the following would you expect to have the lowest resting...
Heart rate is controlled by neurons of the cardiovascular center...
When will the blood pressure be greater?
The heart is innervated by ________ nerves.
Arteriosclerosis can lead to
Which of the following affects blood flow through the body?
Which of the following are characteristics of cardiovascular...
The ________ ventricle has a greater workload than the ________.
The hormone that produces cardiovascular effects similar to activation...
When the left ventricle contracts, the diameter of the ventricular...
Stroke volume depends on
In the middle of the thoracic cavity is a region occupied by the...
The atrioventricular valves permit blood flow
When the semilunar valves close, the AV valves then
Which of the following would have the greater effect on vascular...
The continual movement of fluid through the interstitial spaces...
Edema is favored when
The earlike extension of the atrium is the
Cardiac output is increased by
The function of the atrium is to
Use Figure 18-1 to answer the following questions:...
Which of the following is greater during left ventricular systole?
The following are structural components of the conducting system of...
During exercise
After losing 25 percent of blood volume in a motorcycle accident,...
Turbulent blood flow occurs
Materials can move across capillary walls by
Pacemaker cells isolated from the SA node generate action potentials...
________ is to slow heart rate as ________ is to fast heart rate.
Exchange between a blood vessel and the cells that surround it can...
To defend blood volume against dehydration, the body
The right ventricle pumps blood to the
The left ventricle pumps blood to the
The pulmonary arteries carry blood to the
The pulmonary veins carry blood to the
Use Figure 18-1 to answer the following questions:...
The bicuspid or mitral valve is located
Most of the middle layer in the heart wall is composed of
As a result of the long refractory period in the cardiac action...
There are ________ pulmonary veins.
In response to hemorrhage, there is
Which of the following would be greater?
When the left ventricle contracts, the distance from the apex to the...
Averaged over a few heartbeats, venous return is ________ cardiac...
Blood pressure increases with all of the following, except increased
Which of the following would increase heart rate?
The interventricular sulci and coronary sulcus contain
The phase in the cardiac cycle when the mitral valve is closed and the...
The volume of blood ejected from each ventricle during a contraction...
At a heart rate of 60 beats/minute, a cardiac cycle lasts
Acetylcholine slows the heart because it
Use Figure 18-1 to answer the following questions:...
The term used to describe fluid collecting in the pericardial cavity...
The heart beats approximately ________ times each day.
As blood leaves the right ventricle it passes through the ________ and...
The difference between the systolic and diastolic pressures is called...
Activation of which kind of receptor causes heart rate to increase?
Use Figure 18-1 to answer the following questions:...
Rupture of the papillary muscles in the left ventricle may result in
In which of the following would the resistance be greater?
Use Figure 18-2 to answer the following question:...
Which of the following descriptions matches the term near the left...
Intercalated discs serve to transfer ________ from cell to cell.
The right atrium receives blood from the
The wall of the left ventricle is thicker than the right because
Total peripheral resistance is related to all of the following, except...
If the pacemaker cells in the SA node become more permeable to...
Venoconstriction ________ the amount of blood within the venous...
The AV node delivers the stimulus to the AV bundle, located within the...
Drugs that block the beta-one adrenergic receptors will
Blood flowing into the heart from the venae cavae flows next through...
During the cardiac cycle, the
Abnormally slow depolarization of the ventricles would most change the...
The first heart sound is heard when the
Blood pressure is highest here.
Use Figure 18-1 to answer the following questions:...
________ is to contraction as ________ is to relaxation.
During ventricular systole, the
In which of the following would the blood flow be highest?
If blood pressure doubled, the blood flow through a vessel would be
Blood pressure is lowest in the
The heart pumps approximately ________ milliliters of blood each...
The blood colloid osmotic pressure mostly depends on the
The visceral pericardium is the same as the
Depolarization of the ventricles is represented on an...
Compared to the right ventricle, the left ventricle has all the...
The following is a list of vessels and structures that are associated...
The mitral valve closes
Each of the following will cause an increase in blood pressure, except
Which of the following changes doesn't occur during exercise...
The ________ deliver(s) blood to the myocardium.
The ________ valve prevents backward flow into the left atrium.
If a person has a blood pressure of 120/90, his mean arterial pressure...
In comparing a trained athlete to a non-athlete, which of these...
The cusps (leaflets) of atrioventricular valves attach directly to
Complications related to arteriosclerosis account for roughly ________...
The normal pacemaker of the heart is located in the
When renin is released from the kidney
In cardiac muscle, the fast depolarization phase of the action...
Blood leaves the right ventricle by passing through the
Analysis of the electrocardiogram can reveal all of the following,...
Depolarization of the atria corresponds to the ECG's
Blood is supplied to the myocardium by
The P wave of the electrocardiogram is a signal from
Contractions of the papillary muscles
As blood travels from arteries to veins,
Which of the following factors will increase the net filtration...
The coronary sulcus is a groove that
Cardiac output can be increased by all of the following except one....
David suffers from a prolapsed mitral valve. This condition would...
Each of the following will lead to a decrease in blood pressure,...
Blood returning to the heart from the systemic circuit first enters...
Blood returning to the heart from the pulmonary circuit first enters...
Which of these would cause stroke volume to increase?
The T wave on an ECG tracing represents
The foramen ovale in the fetal heart is located in the  
The vascular pressure that declines from roughly 35 mm Hg to about 18...
Stimulation of the aortic baroreceptors results in
The first blood vessels to branch from the aorta are the ________...
ADH and aldosterone secretion are part of the body's long-term...
Each of the following changes will result in increased blood flow to a...
The main control of peripheral resistance by the vasomotor centers...
The cardioacceleratory center activates sympathetic neurons and the...
During the T wave of the electrocardiogram, the ventricles are
The great and middle cardiac veins drain blood into the
Drugs known as calcium channel blockers such as nifedipine can be used...
Use Figure 18-2 to answer the following question:...
Which of the following statements is false concerning the movement of...
If the connection between the SA node and AV node becomes blocked,
The long plateau phase of the cardiac muscle action potential is due...
The first heart sound ("lubb")
Increased levels of carbon dioxide in the blood will result in...
Tetanic muscle contractions don't occur in a normal cardiac muscle...
Homeostatic mechanisms in response to blood loss include all of the...
If there is a complete block between the SA node and the AV node, how...
Blood is supplied to the left atrium by the
Pacemaker cells in the SA node
The marginal branch and posterior interventricular branch are branches...
The circumflex branch and the anterior interventricular artery are...
Each of the following factors will increase cardiac output, except
Coronary veins empty into the
An increase in the rate of action potentials from baroreceptors will...
In cardiac muscle
The pulmonary semilunar valve prevents backward flow into the
Each of the following factors would increase peripheral resistance,...
Use Figure 18-2 to answer the following question:...
If the connection between the vagus nerve and the heart is cut, which...
Use Figure 18-2 to answer the following question:...
Paul has a horrible chainsaw accident and cuts several major blood...
During the isovolumetric contraction phase of ventricular systole, the
Use Figure 18-2 to answer the following question:...
What effect would compressing the inferior vena cava just below the...
If a patient's tricuspid valve was leaking during systole, what...
Blood flow to a tissue will increase if the
Alert!

Advertisement