Atrioventricular (Av) Valves Quiz Questions

The correct answer is four because the heart is divided into four chambers: two atria and two ventricles. The atria receive blood from the body and lungs, while the ventricles pump blood out to the body and lungs. This division of chambers allows for efficient circulation of oxygenated and deoxygenated blood throughout the body.

The left atrium collects blood from the pulmonary circuit and empties it into the left ventricle. The pulmonary circuit is responsible for carrying oxygen-depleted blood from the heart to the lungs to be oxygenated and then returning oxygen-rich blood back to the heart. Therefore, it makes sense that the left atrium would receive blood from this circuit before it is pumped into the left ventricle.

The heart pumps blood through two circuits. This is because the heart is divided into two sides, the left and right sides. The right side of the heart pumps oxygen-poor blood to the lungs for oxygenation, while the left side of the heart pumps oxygen-rich blood to the rest of the body. These two circuits, known as the pulmonary circuit and systemic circuit, allow for the exchange of oxygen and nutrients throughout the body.

A section through the wall of the heart reveals three layers. The heart wall is made up of three distinct layers: the epicardium, the myocardium, and the endocardium. The epicardium is the outermost layer, which protects the heart and secretes a lubricating fluid. The myocardium is the middle layer, consisting of cardiac muscle tissue that contracts to pump blood. The endocardium is the innermost layer, providing a smooth lining for the chambers of the heart and the valves. Therefore, when a section is taken through the wall of the heart, all three layers can be observed.

The correct answer is endocardium. The inner surfaces of the heart are lined with endocardium, which is a thin layer of tissue that provides a smooth surface for blood to flow through the heart chambers. The endocardium also helps to prevent blood clots from forming inside the heart.

The right atrioventricular valve is also called the tricuspid valve. This valve is located between the right atrium and the right ventricle of the heart. It consists of three flaps or cusps, which allow blood to flow from the atrium to the ventricle during the heart's relaxation phase (diastole) and prevent backflow of blood when the ventricle contracts (systole).

The atrioventricular valves are located between the atria and ventricles in the heart. Their main function is to allow blood flow from the atria to the ventricles during the relaxation phase of the heart (diastole). This prevents backflow of blood from the ventricles to the atria, ensuring that blood moves in the correct direction through the heart. Therefore, the correct answer is "from the atria to the ventricles only."

The correct answer is chordae tendineae. The free edges of the atrioventricular valves are attached to fibers called chordae tendineae. These fibers prevent the valves from inverting or prolapsing when the ventricles contract. They anchor the valves to the papillary muscles, which are located in the ventricles. This arrangement ensures that the valves open and close properly, allowing blood to flow in the correct direction through the heart.

Arteries are the vessels that carry blood away from the heart. They have thick and elastic walls that allow them to withstand the high pressure of blood being pumped from the heart. Arteries branch out into smaller vessels called arterioles, which further divide into capillaries. Capillaries are responsible for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding tissues. Veins, on the other hand, carry blood back to the heart and have thinner walls compared to arteries. Sinusoids are specialized capillaries found in certain organs, such as the liver and spleen, that allow for the passage of larger molecules and cells.

The heart is located near the anterior chest wall. This is because the heart is positioned in the thoracic cavity, specifically in the mediastinum, which is the central compartment of the chest. It is located between the lungs and behind the sternum (breastbone), slightly tilted towards the left side of the chest. This location allows for efficient pumping of blood to the rest of the body.

The left atrium receives blood from the pulmonary veins. The pulmonary veins carry oxygenated blood from the lungs back to the heart. Once the blood enters the left atrium, it is then pumped into the left ventricle and subsequently pumped out to the rest of the body through the aorta. The vena cava, on the other hand, carries deoxygenated blood from the body back to the right atrium. Therefore, the correct answer is pulmonary veins.

The correct answer is "atria" because the atria are the upper chambers of the heart and they contract first during a heartbeat. This contraction allows blood to flow into the ventricles before they contract and pump the blood out of the heart. The mitral valve is a valve located between the left atrium and left ventricle, but it is not the first to contract.

The right and left ventricles are separated from one another by the anterior interventricular sulcus and the posterior interventricular sulcus. These sulci are grooves on the surface of the heart that mark the boundaries between the ventricles. The anterior interventricular sulcus runs along the front of the heart, while the posterior interventricular sulcus runs along the back. Therefore, the correct answer is that both B (anterior interventricular sulcus) and C (posterior interventricular sulcus) separate the right and left ventricles.

The plateau in a cardiac muscle action potential is due to slow calcium channels. These channels open during the plateau phase of the action potential and allow calcium ions to enter the cell. This influx of calcium ions helps to maintain the depolarization of the cell membrane, prolonging the action potential and allowing for sustained contraction of the cardiac muscle. The slow calcium channels also play a role in regulating the timing and strength of the cardiac muscle contraction.

The action potential of cardiac muscles consists of three phases. This is because the action potential in cardiac muscles is longer and more complex compared to other types of muscles. The three phases are the rapid depolarization phase, the plateau phase, and the repolarization phase. During the rapid depolarization phase, there is a rapid influx of sodium ions into the cell, causing a rapid increase in membrane potential. The plateau phase is characterized by a prolonged depolarization due to the influx of calcium ions. Finally, during the repolarization phase, there is an efflux of potassium ions, leading to the restoration of the resting membrane potential.

The right atrium receives blood from the coronary sinus, which drains deoxygenated blood from the heart muscle itself. It also receives blood from the superior vena cava, which brings deoxygenated blood from the upper body, and the inferior vena cava, which brings deoxygenated blood from the lower body. Therefore, all of the above options are correct.

The heart is supplied with blood through two major arteries: the left coronary artery and the right coronary artery. These arteries branch out into smaller blood vessels, ensuring that the heart receives a sufficient supply of oxygenated blood. Having two major arteries helps to ensure that the heart is adequately perfused and can function properly.

Action potentials in cardiac muscle cells last about 250 msec. This is because the action potential in cardiac muscle cells is longer than in other types of muscle cells, such as skeletal muscle cells. The longer duration of the action potential allows for a longer contraction of the cardiac muscle, which is necessary for the pumping action of the heart.

The sinoatrial node is considered the functional pacemaker of the heart because it initiates the electrical impulses that regulate the heart's rhythm. Located in the right atrium, the sinoatrial node generates an electrical signal that spreads across the atria, causing them to contract. This signal then reaches the atrioventricular node, which delays the impulse before transmitting it to the ventricles through the bundle branches and Purkinje fibers. However, the sinoatrial node is responsible for setting the pace and rhythm of the heart, making it the primary pacemaker.

The expandable outer portion of each atrium is called the auricle. The auricle helps to increase the capacity of the atrium to hold blood, allowing for more efficient filling of the ventricles. It is also sometimes referred to as the atrial appendage.

The heart muscle is covered by a membrane called the visceral pericardium. The visceral pericardium is also known as the epicardium and it is the innermost layer of the pericardial sac. It is a thin, smooth membrane that closely adheres to the surface of the heart muscle, providing protection and lubrication. The parietal pericardium is the outer layer of the pericardial sac, while the pericardial cavity is the space between the parietal and visceral pericardium. Therefore, the correct answer is visceral pericardium.

The left atrioventricular valve is also known as the bicuspid valve or the mitral valve.

The correct answer is "Both B and C." The outer layer of the heart is composed of two layers: the epicardium and the visceral pericardium. The epicardium is the outermost layer of the heart, while the visceral pericardium is the inner layer of the pericardium that covers the heart. Therefore, both options B (epicardium) and C (visceral pericardium) are correct.

The refractory period of cardiac muscles is longer than skeletal muscles. This is because cardiac muscles have a longer refractory period to ensure that they have enough time to relax and refill with blood before the next contraction. This is important for the efficient pumping of blood by the heart. In contrast, skeletal muscles have a shorter refractory period as they do not need to continuously contract and relax like the heart muscles.

The great cardiac vein drains the region supplied by the anterior interventricular artery. This is because the anterior interventricular artery, also known as the left anterior descending artery, supplies blood to the anterior surface of the ventricles. Therefore, the great cardiac vein, which runs alongside this artery, drains the blood from this region.

The moderator band is a muscular ridge that is found in the right ventricle of the heart. It extends from the interventricular septum to the anterior papillary muscle. Its main function is to help regulate the tension of the chordae tendineae, which are responsible for preventing the tricuspid valve from prolapsing during ventricular contraction. Therefore, the correct answer is right ventricle.

The phase found only in cardiac muscle is the plateau phase. This phase occurs during the action potential of the cardiac muscle cells and is characterized by a prolonged depolarization. It is called a plateau because the membrane potential remains relatively constant at a high level before repolarization occurs. This phase allows for the sustained contraction of the cardiac muscle, ensuring efficient pumping of blood.

The correct answer is 50. This is the correct answer because the AV node is located near the SA node in the heart, and the electrical impulse generated by the SA node travels through the atria and reaches the AV node in approximately 50 milliseconds.