A&p 2 The Heart
Glands, heart, vessels
- 1.
Normal heart sounds are caused by which of the following events?
- A.
Excitation of the SA node
- B.
Closure of the heart valves
- C.
Friction of blood against the chamber walls
- D.
Opening and closing of the heart valves
Correct Answer
B. Closure of the heart valvesExplanation
Heart sounds are produced by the opening and closing of the heart valves. When the valves close, they create a sound that can be heard with a stethoscope. This closure is an important event in the cardiac cycle as it ensures that blood flows in the correct direction and prevents any backflow. The closure of the heart valves is associated with the second heart sound, known as the "dub" sound. Therefore, the correct answer is closure of the heart valves.Rate this question:
-
- 2.
Which of the events below does not occur when the semilunar valves are open?
- A.
Ventricles are in diastole
- B.
Blood enters pulmonary artieries and the aorta
- C.
Av valves are closed
- D.
Ventricles are in systole
Correct Answer
A. Ventricles are in diastoleExplanation
When the semilunar valves are open, blood enters the pulmonary arteries and the aorta. This occurs during ventricular systole, when the ventricles are contracting and pumping blood out of the heart. Therefore, the event that does not occur when the semilunar valves are open is that the ventricles are in diastole, which is the phase of the cardiac cycle when the ventricles are relaxed and filling with blood.Rate this question:
-
- 3.
Hemrrhage with a large loss of blood causes
- A.
A lowering of blood pressure due to change in cardiac output
- B.
A rise in blood pressure due to change in cardiac output
- C.
No change in blood pressure but a slower heart rate
- D.
No change in blood pressure but a change in respiration
Correct Answer
A. A lowering of blood pressure due to change in cardiac outputExplanation
Hemorrhage with a large loss of blood causes a lowering of blood pressure due to a change in cardiac output. When there is a significant loss of blood, the volume of blood in the circulatory system decreases. This leads to a decrease in the amount of blood being pumped by the heart per minute, known as cardiac output. Since blood pressure is determined by the force exerted by the blood on the walls of the blood vessels, a decrease in cardiac output results in a lowering of blood pressure.Rate this question:
-
- 4.
The left ventricular wall of the heart is thicker than the right wall in order to
- A.
Acoommodate a greater volume of blood
- B.
Expand the thracic cage during diastole
- C.
Pump blood with greater pressure
- D.
Pump blood through a smaller valve
Correct Answer
C. Pump blood with greater pressureExplanation
The left ventricular wall of the heart is thicker than the right wall in order to pump blood with greater pressure. The left ventricle is responsible for pumping oxygenated blood to the entire body, while the right ventricle pumps deoxygenated blood to the lungs. Since the left ventricle has to generate enough force to pump blood throughout the body, its wall is thicker to provide the necessary strength and contractile power. This allows the left ventricle to pump blood with greater pressure, ensuring that oxygenated blood reaches all the organs and tissues efficiently.Rate this question:
-
- 5.
Damage to the__________ is referred to as heart block
- A.
SA node
- B.
AV valves
- C.
AV bundles
- D.
AV node
Correct Answer
D. AV nodeExplanation
Heart block refers to a condition where there is a disruption in the electrical signals that regulate the heartbeat. The AV node, or atrioventricular node, is responsible for transmitting these signals from the atria to the ventricles. If there is damage to the AV node, it can result in a blockage or delay in the transmission of these signals, leading to heart block. Therefore, the correct answer is AV node.Rate this question:
-
- 6.
The p wave of a normal electrocardiogram indicates_____________
- A.
Ventricular repolarization
- B.
Ventricular depolarization
- C.
Atrial repolarization
- D.
Atrial depolarization
Correct Answer
D. Atrial depolarizationExplanation
The P wave of a normal electrocardiogram indicates atrial depolarization. Depolarization refers to the contraction of the heart muscle, and in this case, it specifically refers to the contraction of the atria. The P wave represents the electrical activity that triggers the contraction of the atria, causing them to contract and pump blood into the ventricles. This is followed by the QRS complex, which represents ventricular depolarization and the contraction of the ventricles. Therefore, the correct answer is atrial depolarization.Rate this question:
-
- 7.
Blood within the pulmonary veins returns to the
- A.
Right atrium
- B.
Left atrium
- C.
Right ventricle
- D.
Left ventricle
Correct Answer
B. Left atriumExplanation
The correct answer is left atrium because the pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the heart. Once the blood is oxygenated in the lungs, it enters the left atrium through the pulmonary veins. From there, it will be pumped into the left ventricle and then distributed to the rest of the body.Rate this question:
-
- 8.
Small muscle masses attached to the chordae tendineae are the
- A.
Trabeculae carneae
- B.
Pectinate muscles
- C.
Papillary muscles
- D.
Venae cavae
Correct Answer
C. Papillary musclesExplanation
The correct answer is papillary muscles. The papillary muscles are small muscle masses that are attached to the chordae tendineae, which are fibrous cords that connect the papillary muscles to the cusps of the atrioventricular valves (mitral and tricuspid valves). The contraction of the papillary muscles helps to prevent the valves from inverting or prolapsing during ventricular contraction, ensuring the proper flow of blood through the heart. The trabeculae carneae are irregular muscular ridges on the internal walls of the ventricles, the pectinate muscles are muscular ridges found in the atria, and the venae cavae are large veins that return deoxygenated blood to the heart.Rate this question:
-
- 9.
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is
- A.
Ischemia
- B.
Pericarditis
- C.
Myocardial infarct
- D.
Angina pectoris
Correct Answer
D. Angina pectorisExplanation
Angina pectoris is the correct answer because it refers to the pain that occurs when the heart muscle doesn't receive enough blood due to the temporary narrowing or spasm of the coronary arteries. This can be caused by various factors, including physical exertion, emotional stress, or cold temperatures. It is important to note that angina is not a heart attack (myocardial infarction), but it is a warning sign that there may be an underlying heart condition.Rate this question:
-
- 10.
To auscultate the aortic semilunar valve, you would place your stethoscope in the
- A.
Second intercostal space to the right of the sternum
- B.
Second intercostal space to the left of the sternum
- C.
Fifth intercostal space inferior to the left nipple
- D.
Fifth right intercostal space
Correct Answer
A. Second intercostal space to the right of the sternumExplanation
To auscultate the aortic semilunar valve, the stethoscope should be placed in the second intercostal space to the right of the sternum. This is the correct location because the aortic valve is located in the right side of the sternum, in the second intercostal space. By placing the stethoscope in this specific area, the healthcare professional can effectively listen to the sounds produced by the aortic semilunar valve and assess its function.Rate this question:
-
- 11.
The source of blood carried to capillaries in the myocardium would be the
- A.
Coronary sinus
- B.
Fossa ovalis
- C.
Coronary arteries
- D.
Coronary veins
Correct Answer
C. Coronary arteriesExplanation
The coronary arteries are responsible for supplying oxygenated blood to the capillaries in the myocardium. These arteries branch off from the aorta and directly deliver oxygen and nutrients to the heart muscle. The coronary arteries ensure that the myocardium receives a constant supply of blood to support its high metabolic demands.Rate this question:
-
- 12.
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it
- A.
Pumps a greater volume of blood
- B.
Pumps blood against a greater resistance
- C.
Expands the thoracic cage
- D.
Sends blood through a smaller valve
Correct Answer
B. Pumps blood against a greater resistanceExplanation
The left ventricle of the heart is thicker than the right ventricle because it pumps blood against a greater resistance. The left ventricle is responsible for pumping oxygenated blood to the rest of the body, which requires more force compared to the right ventricle that pumps blood to the lungs for oxygenation. The thicker muscle in the left ventricle allows it to generate more pressure and overcome the higher resistance in the systemic circulation.Rate this question:
-
- 13.
Which of the following factors does not influence heart rate
- A.
Skin color
- B.
Age
- C.
Gender
- D.
Body temperature
Correct Answer
A. Skin colorExplanation
Heart rate is primarily influenced by factors such as age, gender, and body temperature. Skin color, on the other hand, does not directly impact heart rate. While certain medical conditions may cause changes in skin color, these changes do not have a direct effect on the heart rate. Therefore, skin color is not considered a factor that influences heart rate.Rate this question:
-
- 14.
Which of the following is not an age-related change affecting the heart?
- A.
Atherosclerosis
- B.
Decline in cardiac reserve
- C.
Fibrosis of cardiac muscle
- D.
Thinning of the valve flaps
Correct Answer
D. Thinning of the valve flapsExplanation
Thinning of the valve flaps is not an age-related change affecting the heart. As individuals age, they may experience atherosclerosis, which is the build-up of plaque in the arteries, leading to reduced blood flow. There is also a decline in cardiac reserve, which refers to the heart's ability to respond to increased demands. Fibrosis of the cardiac muscle is another age-related change, where there is an increase in the connective tissue in the heart, leading to decreased flexibility. However, thinning of the valve flaps is not a typical age-related change in the heart.Rate this question:
-
- 15.
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from
- A.
Decreased delivery of oxygen
- B.
A decrease in the number of available mitochondria for energy production
- C.
A lack of nutrients to feed into metabolic pathways
- D.
An inadequate supply of lactic acid
Correct Answer
A. Decreased delivery of oxygenExplanation
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from decreased delivery of oxygen. The cardiac muscle requires a constant supply of oxygen to function properly and produce energy through aerobic respiration. Without sufficient oxygen, the cardiac muscle cells cannot generate enough ATP to sustain their metabolic activities, leading to cell dysfunction and damage. This can ultimately result in conditions such as myocardial infarction or heart attack.Rate this question:
-
- 16.
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells
- A.
It would be much longer before cardiac cells could respond to a second stimulation
- B.
Contractions would last as long as the refractory period
- C.
Tetanic contractions might occur, which would stop the hearts pumping action
- D.
It would be less than 1 2 ms
Correct Answer
C. Tetanic contractions might occur, which would stop the hearts pumping actionExplanation
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells, tetanic contractions might occur, which would stop the heart's pumping action. This is because during the refractory period, the cardiac muscle cells are unable to respond to any additional stimulation. If the refractory period is prolonged, it would prevent the heart from contracting effectively and maintaining a normal pumping rhythm, potentially leading to a cessation of the heart's pumping action.Rate this question:
-
- 17.
Norepinephrine acts on the heart by
- A.
Decreasing heart contractility
- B.
Causing a decrease in stroke volume
- C.
Blocking the action of calcium
- D.
Causing threshold to be reached more quickly
Correct Answer
D. Causing threshold to be reached more quicklyExplanation
Norepinephrine acts on the heart by causing the threshold to be reached more quickly. This means that it increases the excitability of the heart cells, making them more likely to generate an action potential. This can lead to an increase in heart rate and contractility, resulting in a stronger and faster heartbeat.Rate this question:
-
- 18.
If the vagal nerves to the heart were cut, the result would be that
- A.
The heart would stop, since the vagal nerves trigger the heart to contract
- B.
The heart rate would increase by about 25 beats per minute
- C.
The av node would become the pacemaker of the heart
- D.
Parasympathetic stimulation would increase, causing a decrease in heart rate
Correct Answer
B. The heart rate would increase by about 25 beats per minuteExplanation
If the vagal nerves to the heart were cut, the parasympathetic stimulation would decrease. This would result in a decrease in the inhibitory signals sent to the heart, causing an increase in heart rate. The vagal nerves are responsible for slowing down the heart rate, so their absence would lead to an increase in heart rate rather than a decrease. However, it is important to note that the exact increase in heart rate may vary from person to person.Rate this question:
-
- 19.
Foramen ovale
- A.
Connects the two atria in the fetal heart
- B.
Is a condition in which the heart valves do not completley close
- C.
Is a shallow depression in the intreventricular septum
- D.
Is a connection between the pulmonary trunk and the aorta in the fetus
Correct Answer
A. Connects the two atria in the fetal heartExplanation
The foramen ovale is a small opening between the two atria in the fetal heart. During fetal development, this opening allows blood to bypass the non-functioning lungs and flow directly from the right atrium to the left atrium. This is important because the lungs are not yet fully developed and cannot perform their normal function of oxygenating the blood. After birth, the foramen ovale typically closes as the lungs begin functioning and the pressure in the heart changes.Rate this question:
-
- 20.
Which vessel of the heart recieves blood during right ventricular systole?
- A.
Venae cavae
- B.
Pulmonary trunk
- C.
Aorta
- D.
Pulmonary veins
Correct Answer
B. Pulmonary trunkExplanation
During right ventricular systole, the right ventricle contracts and pumps blood out of the heart. The pulmonary trunk is the vessel that receives this blood and carries it to the lungs for oxygenation. The vena cavae bring deoxygenated blood from the body back to the right atrium, while the aorta carries oxygenated blood from the left ventricle to the rest of the body. The pulmonary veins, on the other hand, bring oxygenated blood from the lungs to the left atrium.Rate this question:
-
- 21.
Which of these vessels receives blood during ventricular systole?
- A.
Aorta only
- B.
Pulmonary arteries only
- C.
Pulmonary veins only
- D.
Both aorta and pulmonary trunk
Correct Answer
D. Both aorta and pulmonary trunkExplanation
During ventricular systole, the ventricles contract, forcing blood out of the heart. The aorta and pulmonary trunk are the two main vessels that receive this blood. The aorta receives oxygenated blood from the left ventricle and distributes it to the rest of the body, while the pulmonary trunk receives deoxygenated blood from the right ventricle and sends it to the lungs for oxygenation. Therefore, both the aorta and pulmonary trunk receive blood during ventricular systole.Rate this question:
-
- 22.
Which of the following is not part of the conduction system of the heart?
- A.
AV node
- B.
Bundle of His
- C.
AV valve
- D.
SA node
Correct Answer
C. AV valveExplanation
The AV valve, also known as the atrioventricular valve, is not part of the conduction system of the heart. The conduction system consists of specialized cells that generate and transmit electrical signals to coordinate the contraction of the heart muscles. The AV node, bundle of His, and SA node are all components of this conduction system, responsible for regulating the electrical activity and ensuring the proper sequence of contractions in the heart. The AV valve, on the other hand, is a mechanical valve that helps prevent the backflow of blood between the atria and ventricles during the cardiac cycle.Rate this question:
-
- 23.
The tricuspid valve is closed
- A.
While the ventricle is in diastole
- B.
When the ventricle is in systole
- C.
While the atrium is contracting
- D.
By the movement of blood from the atrium to ventricle
Correct Answer
B. When the ventricle is in systoleExplanation
During systole, the ventricle contracts and pumps blood out of the heart to the rest of the body. The tricuspid valve is located between the right atrium and right ventricle and prevents the backflow of blood from the ventricle to the atrium during systole. Therefore, the tricuspid valve is closed when the ventricle is in systole to ensure that blood flows in the correct direction and does not flow back into the atrium.Rate this question:
-
- 24.
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by
- A.
Tracing out where the auricles connect
- B.
Noticing the thickness of the venricle walls
- C.
Locating the apex
- D.
Finding the papillary muscles
Correct Answer
B. Noticing the thickness of the venricle wallsExplanation
The correct answer is "noticing the thickness of the ventricle walls." When viewing a dissected heart, one can visually distinguish the right and left ventricles by observing the thickness of their walls. The left ventricle typically has a thicker wall compared to the right ventricle due to its role in pumping oxygenated blood to the rest of the body, while the right ventricle pumps deoxygenated blood to the lungs. By examining the thickness of the ventricle walls, one can identify and differentiate between the two ventricles.Rate this question:
-
- 25.
Select the correct statement about the heart valves
- A.
The mitral valve seperates the right atrium from the right ventricle
- B.
The tricuspid valve divides the left atrium from the left ventricle
- C.
Aortic and pulmonary valves control the flow of blood into the heart
- D.
The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricle contaction does not occur
Correct Answer
D. The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricle contaction does not occurExplanation
The AV valves, also known as the atrioventricular valves, are supported by chordae tendineae to prevent the backflow of blood into the atria during ventricular contraction. These valves, including the mitral and tricuspid valves, separate the atria from the ventricles and ensure that blood flows in one direction through the heart. The aortic and pulmonary valves, on the other hand, control the flow of blood out of the heart.Rate this question:
-
- 26.
Select the correct statement about the function of myocardial cells
- A.
The entire heart contracts as a unit or it does not contract at all
- B.
Each cardiac muscle cell is nnervated by a sympathetic nerve ending so that the nervous system can increase heart rate
- C.
The refactory period in skeletal muscle is much longer than that in cardiac muscle
- D.
The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction.
Correct Answer
A. The entire heart contracts as a unit or it does not contract at allExplanation
The correct statement about the function of myocardial cells is that the entire heart contracts as a unit or it does not contract at all. This means that the contraction of the heart is coordinated and synchronized, allowing it to pump blood effectively. If the contraction is not coordinated, it can lead to irregular heart rhythms or ineffective pumping.Rate this question:
-
- 27.
Select the correct statement about the structure of the heart wall
- A.
The fibrous skeleton forms the bulk of the heart
- B.
Connective tissue in the heart wall aids in the conduction of the action potential
- C.
The heart chambers are lined by the endomysium
- D.
They myocardium is the layer of the heart that actually contracts
Correct Answer
D. They myocardium is the layer of the heart that actually contractsExplanation
The correct answer is that the myocardium is the layer of the heart that actually contracts. The myocardium is the middle layer of the heart wall and is composed of cardiac muscle tissue. It is responsible for the contraction and relaxation of the heart, which allows it to pump blood throughout the body. The fibrous skeleton, on the other hand, is a dense connective tissue structure that provides structural support and separates the atria from the ventricles. The endomysium is a layer of connective tissue that surrounds individual cardiac muscle fibers. While connective tissue in the heart wall aids in the conduction of the action potential, it is not the primary layer responsible for contraction.Rate this question:
-
- 28.
Compared to skeletal muscle, cardiac muscle
- A.
Has gap junctions that allow it to act as a functional syncytium
- B.
Lacks striations
- C.
Has more nuclei per cell
- D.
Cells are larger than skeletal muscle cells
Correct Answer
A. Has gap junctions that allow it to act as a functional syncytiumExplanation
Cardiac muscle has gap junctions that allow it to act as a functional syncytium. Gap junctions are specialized protein channels that connect adjacent cardiac muscle cells, allowing for the rapid transmission of electrical impulses. This allows the entire cardiac muscle to contract as a coordinated unit, ensuring efficient pumping of blood. Unlike skeletal muscle, cardiac muscle cells are interconnected and function as a single unit, allowing for synchronized contractions. This is essential for the proper functioning of the heart as a pump.Rate this question:
-
- 29.
During the period of ventricular filling
- A.
Pressure in the heart is at its peak
- B.
Blood flows passively through the atria and the open AV valves into the ventricles
- C.
The atria remain in diastole
- D.
It is represented by the P wave on the ECG
Correct Answer
B. Blood flows passively through the atria and the open AV valves into the ventriclesExplanation
During the period of ventricular filling, the pressure in the heart is at its peak. This high pressure causes the blood to flow passively through the atria and the open AV valves into the ventricles. The atria, on the other hand, remain in diastole during this period. The P wave on the ECG represents the electrical activity of the atria, which is also consistent with the blood flowing through the atria and into the ventricles.Rate this question:
-
- 30.
The second heart sound is heard during which phase of the cardiac cylce?
- A.
Isovolumetric relaxation
- B.
Isovolumetric contraction
- C.
Ventricular ejection
- D.
Ventricular filling
Correct Answer
A. Isovolumetric relaxationExplanation
The second heart sound is heard during isovolumetric relaxation. This phase occurs immediately after the closure of the aortic and pulmonary valves, when the ventricles are starting to relax and the pressure within them is decreasing. During this phase, the ventricles are not yet filled with blood, and no blood is being ejected into the arteries. The second heart sound is produced by the closure of the aortic and pulmonary valves and is indicative of the beginning of ventricular relaxation.Rate this question:
-
- 31.
The time of day most hazardous for heart attacks is
- A.
Morning
- B.
Noon time
- C.
Evening
- D.
During sleep
Correct Answer
A. MorningExplanation
The correct answer is morning. Research has shown that the risk of heart attacks is highest in the morning hours. This is because the body's natural circadian rhythm causes an increase in blood pressure and heart rate in the morning, which can trigger a heart attack in individuals with underlying heart conditions. Additionally, morning activities such as waking up, getting out of bed, and starting daily routines can also contribute to the increased risk.Rate this question:
-
- 32.
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid
- A.
Threshold is reached more quickly and heart rate would increase
- B.
Potassium channels compensate and no change in heart rate would occur
- C.
Heart rate would decrease, but blood pressure would rise due to the excess sodium present
- D.
Tetanic contraction would occur due to the short absolute refractory period of cardiac muscle
Correct Answer
A. Threshold is reached more quickly and heart rate would increaseExplanation
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, the threshold for action potential generation would be reached more quickly. This would result in an increased heart rate because the pacemaker cells would fire more frequently, leading to a faster contraction of the heart muscle.Rate this question:
-
- 33.
Select the correct statement about cardiac output
- A.
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction
- B.
Decreased venous return will result in increased end diastolic volume
- C.
If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased
- D.
Stroke volume increasees if end diastolic volume decreases
Correct Answer
A. A slow heart rate increases end diastolic volume, stroke volume, and force of contractionExplanation
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. When the heart rate is slower, the ventricles have more time to fill with blood during diastole, resulting in an increased end diastolic volume. This increased volume leads to a larger stroke volume, which is the amount of blood pumped out of the ventricle with each heartbeat. Additionally, a slower heart rate allows for a longer duration of ventricular contraction, allowing for a more forceful contraction and thus increasing the force of contraction.Rate this question:
-
- 34.
During contraction of hear muscle cells
- A.
The action potential is initiated by voltage-gated slow calcium channels
- B.
Some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
- C.
The action potential is prevented from spreading from cell to cell by gap junctions
- D.
Calcium is prevented from entering cardiac fibers that have been stimulated
Correct Answer
B. Some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular storesExplanation
During the contraction of heart muscle cells, some calcium enters the cell from the extracellular space. This influx of calcium triggers the release of larger amounts of calcium from intracellular stores. This release of calcium is necessary for the contraction of the muscle cells. The action potential is not prevented from spreading from cell to cell by gap junctions, as these gap junctions actually facilitate the spread of the action potential. Additionally, calcium is not prevented from entering cardiac fibers that have been stimulated, as calcium entry is necessary for muscle contraction.Rate this question:
-
- 35.
Isovolumetric contraction
- A.
Refers to the short period during ventricular systole when the ventricles are completely
- B.
Occurs while the AV valves are open
- C.
Occurs immediately after the aortic and pulmonary valves close
- D.
Occurs only in people with heart valve defects
Correct Answer
A. Refers to the short period during ventricular systole when the ventricles are completelyExplanation
Isovolumetric contraction refers to the short period during ventricular systole when the ventricles are completely contracted but the volume of blood in them remains constant. This occurs while the AV valves are closed and the aortic and pulmonary valves have not yet opened. It is a normal part of the cardiac cycle and is not limited to people with heart valve defects.Rate this question:
-
- 36.
Commotio cordis is heart failure due to a
- A.
Mild electrical shock to the heart itself
- B.
Severe electrical shock to the body
- C.
Relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing
- D.
Loss of blood from an artery
Correct Answer
C. Relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizingExplanation
Commotio cordis is a condition where the heart goes into failure due to a relatively mild blow to the chest that happens during a specific vulnerable interval of 2 milliseconds. This vulnerable interval occurs when the heart is repolarizing, which means it is in the process of resetting itself after a heartbeat. During this vulnerable period, even a mild blow to the chest can disrupt the heart's rhythm and lead to sudden cardiac arrest. This condition is not caused by an electrical shock to the heart or body, or by loss of blood from an artery.Rate this question:
-
- 37.
Which of the following is not one of the three main factors influencing blood pressure?
- A.
Cardiac output
- B.
Peripheral resistance
- C.
Emotional state
- D.
Blood volume
Correct Answer
C. Emotional stateExplanation
The three main factors influencing blood pressure are cardiac output, peripheral resistance, and blood volume. Emotional state is not one of these factors. While emotions can temporarily affect blood pressure, they are not considered a main factor because they do not have a long-term impact on blood pressure regulation. Factors like cardiac output, peripheral resistance, and blood volume play more significant roles in determining blood pressure levels.Rate this question:
-
- 38.
Which of hte following chemicals does not help regulate blood pressure?
- A.
ADH
- B.
Atrial natriuretic peptide
- C.
Angiotensin II
- D.
Nitric acid
Correct Answer
D. Nitric acidExplanation
Nitric acid is not involved in the regulation of blood pressure. ADH (antidiuretic hormone) helps regulate blood pressure by increasing water reabsorption in the kidneys. Atrial natriuretic peptide helps lower blood pressure by promoting the excretion of sodium and water in the kidneys. Angiotensin II is a hormone that constricts blood vessels and raises blood pressure. Nitric acid, on the other hand, is a corrosive chemical and not involved in the physiological regulation of blood pressure.Rate this question:
-
- 39.
Which statement best describes arteries
- A.
All carry oxygenated blood to the heart
- B.
All carry blood away from the heart
- C.
All contain valves to prevent the backflow of blood
- D.
Only large arteries are lined with endothelium
Correct Answer
B. All carry blood away from the heartExplanation
Arteries are blood vessels that carry blood away from the heart to various parts of the body. They play a crucial role in the circulatory system by transporting oxygenated blood, nutrients, and hormones to tissues and organs. Unlike veins, arteries do not contain valves to prevent the backflow of blood. Additionally, it is important to note that all arteries, regardless of their size, are lined with endothelium, a thin layer of cells that provides a smooth surface for blood flow.Rate this question:
-
- 40.
Which tunic of an artery contains endothelium?
- A.
Tunica intima
- B.
Tunica media
- C.
Tunica externa
- D.
Basement membrane
Correct Answer
A. Tunica intimaExplanation
The tunica intima of an artery contains endothelium. The tunica intima is the innermost layer of the artery wall and is composed of endothelial cells. These cells form a smooth lining called the endothelium, which helps to reduce friction as blood flows through the artery. The tunica intima also contains a layer of connective tissue and a layer of elastic fibers, which provide structural support to the artery.Rate this question:
-
- 41.
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of
- A.
Arterioles
- B.
Arteries
- C.
Veins
- D.
Capillaries
Correct Answer
D. CapillariesExplanation
Capillaries are the smallest blood vessels in the body and play a crucial role in the exchange of nutrients and gases between the blood and tissue cells. Their thin walls and large surface area allow for efficient diffusion of substances such as oxygen, carbon dioxide, glucose, and waste products. Capillaries connect arterioles (small arteries) and venules (small veins), forming a network throughout the body. This network ensures that every cell in the body receives the necessary oxygen and nutrients while waste products are removed. Therefore, capillaries are responsible for the primary function of permitting the exchange of nutrients and gases between the blood and tissue cells.Rate this question:
-
- 42.
The circulatory route that runs from the digestive tract to the liver is called
- A.
Hepatic portal circulation
- B.
Pulmonary circulation
- C.
Coronary circulation
- D.
Cerebral circulation
Correct Answer
A. Hepatic portal circulationExplanation
Hepatic portal circulation is the correct answer because it refers to the circulatory route that carries blood from the digestive organs to the liver for processing and detoxification. This circulation allows the liver to regulate the levels of nutrients, hormones, and toxins in the blood before it is distributed to the rest of the body. Pulmonary circulation refers to the flow of blood between the heart and the lungs, coronary circulation refers to the blood flow within the heart muscle, and cerebral circulation refers to the blood supply to the brain.Rate this question:
-
- 43.
The arteries that are also called distributing arteries are the
- A.
Elastic arteries
- B.
Muscular arteries
- C.
Arterioles
- D.
Capillaries
Correct Answer
B. Muscular arteriesExplanation
Muscular arteries are also known as distributing arteries because they have a thick layer of smooth muscle in their walls, allowing them to regulate blood flow to specific areas of the body. These arteries are responsible for distributing oxygenated blood from the heart to various organs and tissues. Unlike elastic arteries, which are larger and more elastic, muscular arteries have a smaller diameter and are able to constrict or dilate to control blood flow. Arterioles are smaller branches that connect muscular arteries to capillaries, where the exchange of oxygen and nutrients occurs. Therefore, muscular arteries best fit the description of distributing arteries.Rate this question:
-
- 44.
Aldosterone will
- A.
Promote an increase in blood pressure
- B.
Promote a decrease in blood volume
- C.
Result in a larger ouput of urine
- D.
Decrease sodium reabsorption
Correct Answer
A. Promote an increase in blood pressureExplanation
Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in regulating blood pressure. It acts on the kidneys to increase the reabsorption of sodium and water, leading to an increase in blood volume. This increase in blood volume subsequently raises blood pressure. Therefore, the correct answer is that aldosterone will promote an increase in blood pressure.Rate this question:
-
- 45.
The pulse pressure is
- A.
Systolic pressure plus diastolic pressure
- B.
Systolic pressure minus diastolic pressure
- C.
Systolic pressure divided by diastolic pressure
- D.
Diastolic pressure plus 1/3 (systolic pressure plus diastolic pressure)
Correct Answer
B. Systolic pressure minus diastolic pressureExplanation
Pulse pressure is defined as the difference between the systolic pressure (the highest pressure in the arteries during a cardiac cycle) and the diastolic pressure (the lowest pressure in the arteries during a cardiac cycle). Therefore, the correct answer is "systolic pressure minus diastolic pressure". This calculation provides a measure of the force exerted by the heart with each heartbeat and can be used as an indicator of cardiovascular health.Rate this question:
-
- 46.
Which of the following signs of hypovolemic shock is a relatively late sign?
- A.
Cold, clammy skin
- B.
Increased heart rate
- C.
Rapid, thready pulse
- D.
Rapildy falling blood pressure
Correct Answer
D. Rapildy falling blood pressureExplanation
A rapidly falling blood pressure is a relatively late sign of hypovolemic shock. When a person experiences hypovolemic shock, their blood volume decreases significantly, leading to inadequate perfusion of organs and tissues. Initially, the body compensates for this by increasing the heart rate to maintain blood flow. However, as the condition worsens, the blood pressure starts to drop rapidly. Therefore, a rapidly falling blood pressure indicates that the body's compensatory mechanisms are failing, making it a late sign of hypovolemic shock.Rate this question:
-
- 47.
Which of the following is likely during vigorous exercise?
- A.
Blood will be deverted to the digestive organs
- B.
The skin will be cold and clammy
- C.
Capillaries of the active muscles will be engorged with blood
- D.
Blood flow to the kidneys increases
Correct Answer
C. Capillaries of the active muscles will be engorged with bloodExplanation
During vigorous exercise, the body requires increased oxygen and nutrients to the active muscles. To meet this demand, capillaries in the active muscles dilate and become engorged with blood. This allows for increased blood flow, delivering more oxygen and nutrients to the muscles, and removing waste products such as carbon dioxide. This process helps to support the increased energy demands of the muscles during exercise.Rate this question:
-
- 48.
Which of the choices below explains why the artreioles are known as resistance vessels?
- A.
Their prime function is the exchange of nutrients and wastes between the blood and tissue cells
- B.
The contraction and realxation of the smooth muscle in their walls can change their diameter
- C.
They distribute blood to various parts of the body
- D.
They contain a large quantity of elastic tissue
Correct Answer
B. The contraction and realxation of the smooth muscle in their walls can change their diameterExplanation
Arterioles are known as resistance vessels because the contraction and relaxation of the smooth muscle in their walls can change their diameter. This ability allows arterioles to regulate blood flow and control the resistance to blood flow in different parts of the body. When the smooth muscle contracts, the arterioles constrict, increasing resistance and reducing blood flow. Conversely, when the smooth muscle relaxes, the arterioles dilate, decreasing resistance and increasing blood flow. This dynamic adjustment of arteriolar diameter helps regulate blood pressure and ensure that organs and tissues receive the appropriate amount of blood supply.Rate this question:
-
- 49.
Which of the following is true about veins?
- A.
Venous valves are formed from the tunica media
- B.
Up to 35% of total body blood is in venous circulation at any given time
- C.
Veins have a small lumen in relation to the thickness of the vessel wall
- D.
Veins are called capacitance vessels or blood reservoirs
Correct Answer
D. Veins are called capacitance vessels or blood reservoirsExplanation
Veins are called capacitance vessels or blood reservoirs because they have the ability to stretch and hold a large volume of blood. This allows them to serve as a storage system for blood, which can be quickly released back into circulation when needed. Veins have thinner walls and a larger lumen compared to arteries, allowing them to accommodate this increased blood volume.Rate this question:
-
- 50.
Which of the following processes provides a long-term response to changes in blood pressure?
- A.
Neural controls
- B.
Baroreceptor-initiated reflexes
- C.
Chemoreceptor-initiated reflexes
- D.
Renal regulation
Correct Answer
D. Renal regulationExplanation
Renal regulation provides a long-term response to changes in blood pressure. The kidneys play a crucial role in regulating blood pressure by adjusting the amount of water and salt reabsorbed or excreted in the urine. When blood pressure is high, the kidneys increase the excretion of water and salt, reducing blood volume and lowering blood pressure. Conversely, when blood pressure is low, the kidneys conserve water and salt, increasing blood volume and raising blood pressure. This process helps maintain blood pressure within a normal range over an extended period of time.Rate this question:
-
Back to top