Anatomy And Physiology Of Cardiovascular System Quiz

The SA (sinoatrial) node is often referred to as the "pacemaker" of the heart because it is responsible for initiating the electrical impulses that regulate the heart's rhythm. Located in the right atrium, the SA node generates electrical signals that cause the atria to contract, initiating the heartbeat. These signals then travel through the AV node, AV bundle, and Purkinje fibers, coordinating the contraction of the ventricles. However, it is the SA node that sets the pace for the entire cardiac cycle, making it the pacemaker of the heart.

Increasing sodium levels can lead to an increase in heart rate and contractility. Sodium plays a crucial role in maintaining the balance of electrolytes in the body, including the heart. When sodium levels increase, it can disrupt the balance of ions in the heart, causing an increase in heart rate. Additionally, higher sodium levels can also affect the contractility of the heart, leading to stronger and more forceful contractions. Therefore, increasing sodium can have a stimulatory effect on the heart, resulting in an increase in heart rate and contractility.

The mitral valve is also known as the left AV valve. This valve is located between the left atrium and the left ventricle of the heart. It consists of two flaps or leaflets that open and close to regulate the flow of blood from the atrium to the ventricle. The left AV valve prevents the backflow of blood from the ventricle to the atrium during ventricular contraction, ensuring that blood flows in one direction through the heart.

The heart wall is composed of three layers: the epicardium, myocardium, and endocardium. The fibrous layer of pericardium is not part of the heart wall, but rather a separate layer that surrounds and protects the heart. It is a tough, fibrous sac that helps to anchor the heart in place and prevent overstretching.

Ca (calcium) is responsible for the plateau phase. The plateau phase refers to the phase in the action potential of cardiac muscle cells where there is a prolonged period of depolarization and the membrane potential remains elevated. This phase is crucial for the contraction of the heart muscle. Calcium ions play a key role in this phase by entering the cardiac muscle cells and triggering the release of more calcium from the sarcoplasmic reticulum, leading to sustained muscle contraction.

In an adult, the ductus arteriosus becomes ligamentous arteriosus. The ductus arteriosus is a blood vessel that connects the pulmonary artery to the aorta in a fetus. It allows blood to bypass the lungs since the fetus receives oxygen from the placenta. After birth, when the baby starts breathing on its own, the ductus arteriosus gradually closes and eventually becomes a ligamentous structure known as the ligamentous arteriosus. This transformation is a normal part of postnatal development.

Cardiac output refers to the volume of blood pumped out of each ventricle every minute. This is an important measure of the efficiency and effectiveness of the heart's pumping action. It indicates the amount of blood that is being circulated throughout the body per minute, which is crucial for delivering oxygen and nutrients to the tissues and organs. Monitoring and maintaining an adequate cardiac output is essential for overall cardiovascular health.

The cardiac skeleton serves to stabilize the valves and electrically insulate the ventricles from the atria. It provides structural support for the valves, ensuring proper function and preventing backflow of blood. Additionally, it acts as an electrical insulator, preventing the spread of electrical signals from the atria to the ventricles, thus maintaining the coordinated contraction of the heart chambers.

The visceral layer of the pericardium is also called the epicardium. The pericardium is a double-layered sac that surrounds the heart. The visceral layer is the inner layer that directly covers the surface of the heart. It is composed of connective tissue and contains blood vessels, nerves, and fat. The epicardium plays a crucial role in protecting the heart and providing a smooth surface for the heart to contract and relax.

Potassium (K) is responsible for the repolarization of the cell. During an action potential, the cell depolarizes as sodium (Na) ions enter the cell. Once the cell reaches its peak depolarization, potassium channels open, allowing potassium ions to leave the cell. This efflux of potassium ions causes the cell to repolarize, returning the cell to its resting membrane potential. Therefore, K is responsible for the repolarization phase of the action potential.

The "DUB" or S2 heart sound is responsible for the closure of the pulmonary and aortic valves. When the ventricles contract and the pressure inside them exceeds the pressure in the pulmonary artery and aorta so that blood flows out until systole is complete, then the pulmonary and aortic valves close. This closure produces the "DUB" sound, marking the end of systole and the beginning of diastole.

The "LUB" or S1 sound of the heart is caused by the closure of the mitral and tricuspid valves. These valves are located between the atria and ventricles of the heart and prevent the backflow of blood when the ventricles contract. When the ventricles contract, the mitral and tricuspid valves close, creating the first heart sound. This sound can be heard as a "LUB" and indicates the beginning of the systolic phase of the cardiac cycle.

The lungs are not located in the mediastinum. The mediastinum is the central compartment of the thoracic cavity, located between the two lungs. It contains various structures such as the heart, esophagus, and trachea. However, the lungs are situated on either side of the mediastinum, filling the pleural cavities.

When heart rate decreases, all phases of the cardiac cycle do not shorten. In fact, when heart rate decreases, the duration of each phase of the cardiac cycle tends to increase. This is because a slower heart rate allows more time for the heart to fill with blood during diastole and for blood to be ejected during systole. Therefore, the correct answer is False.

The rapid depolarization of a cell is primarily caused by the influx of sodium ions (Na+) into the cell. When a cell is at rest, there is a higher concentration of sodium ions outside the cell compared to inside. However, during depolarization, voltage-gated sodium channels open, allowing sodium ions to rush into the cell. This influx of positive ions leads to a rapid change in the cell's membrane potential, causing depolarization. Chloride (Cl-), potassium (K+), and calcium (Ca2+) ions do not play a significant role in the rapid depolarization of a cell.

A portal system is a specialized arrangement of blood vessels that allows blood to flow from one capillary bed to another without passing through the heart. It consists of two sets of capillaries connected by a portal vein. In this context, the correct answer is capillaries because they are one of the components that make up a portal system. Venules, arteries, and arterioles are not specifically associated with portal systems.

The coronary sinus is located in the right atrium. The coronary sinus is a vein that collects deoxygenated blood from the heart muscle and returns it to the right atrium. It is an important part of the cardiac circulation system, allowing for the drainage of waste products and the delivery of oxygen and nutrients to the heart muscle.

Contractility refers to the strength or force with which the heart muscle contracts. It is a measure of the heart's ability to contract and pump blood effectively. The greater the contractility, the stronger the force of contraction, leading to a more efficient pumping of blood throughout the body. This is an important factor in maintaining proper cardiac output and ensuring adequate blood flow to meet the body's demands.

Hypovolemic shock is a condition characterized by a significant decrease in blood volume, leading to inadequate perfusion of organs and tissues. The correct answer, "massive amount of blood loss," aligns with this definition. When a large amount of blood is lost, either through trauma, internal bleeding, or other causes, the body's blood volume decreases rapidly. As a result, the heart is unable to pump enough blood to meet the body's oxygen and nutrient needs, leading to hypovolemic shock.

The mitral valve is most commonly associated with murmurs. Murmurs are abnormal sounds heard during the heartbeat and can indicate a problem with the flow of blood through the heart. The mitral valve is located between the left atrium and the left ventricle and is responsible for preventing the backflow of blood into the left atrium during ventricular contraction. Any disruption in the functioning of the mitral valve can lead to the development of a murmur.

The amount of elastic fibers in the tunica media does not affect vascular resistance. Vascular resistance is primarily determined by factors such as lumen size, blood viscosity, and total vessel length. Elastic fibers in the tunica media play a role in maintaining the elasticity and integrity of blood vessels, but they do not directly impact the resistance to blood flow.

The Trabeculae Septomarginalis is located in the Right Ventricle.

Pectinate muscles are found in the atria. These muscles are responsible for increasing the surface area of the atrial wall, allowing for more efficient contraction and blood flow. They are named "pectinate" due to their comb-like appearance.

ADH, or antidiuretic hormone, is responsible for vasoconstriction. Vasoconstriction refers to the narrowing of blood vessels, which increases blood pressure and reduces blood flow to certain areas of the body. ADH acts on the smooth muscle cells in the walls of blood vessels, causing them to contract and constrict. This helps regulate blood volume and maintain blood pressure within a normal range.

Preload refers to the amount of stretch that the heart muscle experiences before it contracts. This stretch is important because it determines the force with which the heart contracts and the amount of blood that is ejected from the heart. When the heart muscle stretches, it allows for a greater volume of blood to fill the heart chambers, leading to a more forceful contraction and a larger volume of blood being ejected per beat. Therefore, the correct answer is "amount of the heart muscle must stretch before contraction".

The question is asking for the wave that indicates the repolarization of the atria. The P wave represents the depolarization of the atria, not the repolarization. The QRS wave represents the depolarization of the ventricles. The T wave represents the repolarization of the ventricles, not the atria. Therefore, none of the given options indicate the repolarization of the atria.

The S3 heart sound is a low-frequency sound that occurs during the rapid filling of the ventricles. It is typically heard in large animals and can indicate increased blood volume or fluid overload in the ventricles. Therefore, the correct answer is ventricular filling.

During the isovolumetric ventricular contraction phase of the cardiac cycle, all valves in the heart are closed. This phase occurs after the atria have contracted and the ventricles are beginning to contract. The closure of the valves prevents blood from flowing back into the atria and out of the ventricles, allowing the ventricles to build up pressure. Once the pressure in the ventricles exceeds the pressure in the aorta, the aortic valve opens and blood is ejected into the systemic circulation. Therefore, during the isovolumetric ventricular contraction phase, all valves are closed to ensure efficient pumping of blood.

During atrial depolarization, the electrical signal is generated in the atria causing them to contract. This contraction increases the pressure in the atria, forcing blood into the ventricles. At this phase, the pulmonic and aortic valves are closed to prevent backflow of blood into the atria. Simultaneously, the atrioventricular valves are open, allowing blood to flow from the atria into the ventricles. This phase is known as atrial systole and marks the beginning of ventricular filling.

Oncotic pressure is a result of proteins. Proteins in the blood, such as albumin, exert an osmotic pressure that helps to maintain fluid balance between the blood vessels and the surrounding tissues. This pressure helps to draw water back into the blood vessels and prevent excessive fluid accumulation in the tissues. Therefore, proteins play a crucial role in regulating oncotic pressure and maintaining normal fluid distribution in the body.

The atrial (bainbridge) reflex adjusts heart rate in response to venous return. When the atria of the heart are stretched due to an increase in blood volume, sensory receptors in the atria send signals to the cardioinhibitory center in the medulla oblongata. This center then inhibits parasympathetic output and increases sympathetic output, leading to an increase in heart rate. This reflex helps to maintain adequate cardiac output in response to changes in venous return.

The left atrium is not associated with systemic circulation because it receives oxygenated blood from the lungs via the pulmonary veins and then pumps it into the left ventricle, which is responsible for pumping blood into the systemic circulation. The left atrium is part of the pulmonary circulation, which is responsible for oxygenating the blood.

The S4 heart sound is known as an atrial gallop and is typically heard in large animals. It occurs during atrial contraction, which is the phase where the atria contract to push blood into the ventricles. This sound is usually associated with conditions such as hypertrophic cardiomyopathy or a stiff ventricle, where the ventricle has difficulty relaxing and filling properly. Therefore, the correct answer is atrial contraction.