Kin 560 - Exam 1

The cordae tendonae are fibrous cords that attach the cusps of the atrioventricular valves to the papillary muscles in the ventricles. These cords play a crucial role in preventing the valves from everting or flipping inside out during ventricular contraction. They help to anchor the valves in place and ensure that blood flows in the correct direction, preventing any backflow or regurgitation.

Diastole is actually the phase of the cardiac cycle when the myocardium relaxes and the heart chambers fill with blood. It is the opposite of systole, which is the phase when the myocardium contracts and pumps blood out of the heart. Therefore, the statement in the question is incorrect, and the correct answer is False.

Blood entering the left atrium is oxygenated because the left atrium receives blood from the pulmonary veins, which carry oxygenated blood from the lungs. From the left atrium, the oxygenated blood is then pumped into the left ventricle and subsequently to the rest of the body through the aorta.

The bicuspid valve, also known as the mitral valve, is located between the left atrium and ventricle of the heart. It consists of two flaps that open and close to allow blood to flow from the atrium to the ventricle and prevent backflow. This valve is responsible for ensuring that oxygenated blood from the lungs is pumped out to the rest of the body, while preventing it from flowing back into the atrium.

The heart ejects deoxygenated blood through the pulmonary arteries. After the blood is pumped from the right ventricle, it flows into the pulmonary arteries, which carry it to the lungs for oxygenation. In the lungs, carbon dioxide is released, and oxygen is absorbed, transforming the deoxygenated blood into oxygenated blood. The oxygenated blood then returns to the heart through the pulmonary veins, completing the cycle of blood circulation. Therefore, the correct answer is pulmonary arteries.

The tricuspid valve is located between the right atrium and ventricle. It consists of three leaflets or cusps that open and close to regulate blood flow. When the right atrium contracts, the tricuspid valve opens, allowing blood to flow into the right ventricle. When the right ventricle contracts, the tricuspid valve closes to prevent backflow of blood into the atrium. This valve plays a crucial role in maintaining the unidirectional flow of blood through the heart.

Deoxygenated blood from the systemic circulation enters the right atrium of the heart. This is because after oxygen is extracted from the body's tissues, the deoxygenated blood returns to the heart through the superior and inferior vena cava. These veins carry the blood to the right atrium, which acts as a receiving chamber. From the right atrium, the blood is then pumped into the right ventricle, which will eventually pump it to the lungs for oxygenation. Therefore, the correct answer is the right atrium.

Systole refers to the phase of the cardiac cycle when the myocardium, which is the muscular tissue of the heart, contracts. This contraction helps to pump blood out of the heart and into the arteries, allowing it to be distributed throughout the body. Therefore, the statement "Systole is when the myocardium contracts" is true.

Blood entering the right atrium is deoxygenated because it has already circulated through the body and delivered oxygen to the cells. It then returns to the heart through the superior and inferior vena cava, entering the right atrium. From there, it will be pumped into the right ventricle and eventually sent to the lungs to be oxygenated again.

Oxygenated blood enters the heart through the pulmonary veins, which carry the blood from the lungs back to the heart. The pulmonary veins empty into the left atrium, which is responsible for receiving the oxygenated blood. From the left atrium, the blood then flows into the left ventricle, which pumps the oxygenated blood out to the rest of the body. Therefore, the correct answer is the left atrium.

The pulmonary artery receives blood from the right ventricle of the heart. After the right ventricle contracts, it pumps deoxygenated blood into the pulmonary artery, which then carries the blood to the lungs for oxygenation. This is an important step in the pulmonary circulation system, where the blood picks up oxygen and releases carbon dioxide before returning to the heart.

During atrial diastole/ventricular systole, the pulmonary valve is open because this is the phase of the cardiac cycle when the ventricles are contracting (ventricular systole) and the atria are relaxed (atrial diastole). In this phase, the pressure in the right ventricle exceeds the pressure in the pulmonary artery, causing the pulmonary valve to open and allowing blood to be pumped from the right ventricle to the lungs for oxygenation. Therefore, the statement is true.

The aorta receives blood from the left ventricle of the heart. The left ventricle is responsible for pumping oxygenated blood to the rest of the body through the aorta, which is the largest artery in the body. This is because the left ventricle receives oxygen-rich blood from the left atrium and then contracts to push the blood into the aorta, allowing it to be distributed to all the organs and tissues.

During atrial systole, the atria contract and push blood into the ventricles. At the same time, the tricuspid valve, located between the right atrium and right ventricle, is open to allow blood to flow from the atrium into the ventricle. This is necessary for the proper filling of the ventricles before they contract during ventricular systole. Therefore, the statement that the tricuspid valve is open during atrial systole is true.

The heart receives oxygenated blood from the pulmonary veins. The pulmonary veins are responsible for carrying oxygenated blood from the lungs back to the heart. After the blood is oxygenated in the lungs, it is transported through the pulmonary veins and enters the left atrium of the heart. From there, it is pumped into the left ventricle and then distributed to the rest of the body through the aorta. Therefore, the correct answer is the pulmonary veins.

During atrial systole/ventricular diastole, the bicuspid valve is actually open. This is because atrial systole refers to the contraction of the atria, which leads to the opening of the bicuspid valve, allowing blood to flow from the left atrium into the left ventricle. Ventricular diastole, on the other hand, is the relaxation phase of the ventricles, during which the bicuspid valve remains open to facilitate the filling of the left ventricle with blood. Therefore, the correct answer is false.

The correct answer is the coronary sinus. The coronary sinus is responsible for draining venous blood from the myocardium. It is a large vessel located in the posterior part of the heart and receives blood from the cardiac veins. This blood is then emptied into the right atrium of the heart. The superior and inferior vena cava are responsible for draining blood from other parts of the body into the right atrium, but they do not specifically drain blood from the myocardium.

During atrial diastole, the atria are relaxed and filling with blood. During ventricular systole, the ventricles contract and pump blood out of the heart. In both of these phases, the aortic valve is open to allow blood to flow from the left ventricle into the aorta. Therefore, the correct answer is false.

The superior vena cava is responsible for draining venous blood from the upper portion of the body. It is a large vein that carries deoxygenated blood from the head, neck, arms, and upper chest back to the heart. The blood then enters the right atrium of the heart, where it is pumped to the lungs for oxygenation. The inferior vena cava, on the other hand, drains venous blood from the lower portion of the body. The coronary sinus is a smaller vein that drains blood from the heart muscle itself. Therefore, the correct answer is the superior vena cava.

The aortic valve prevents backflow into the left ventricle. It is located between the left ventricle and the aorta, the main artery that carries oxygenated blood to the rest of the body. When the left ventricle contracts and pumps blood into the aorta, the aortic valve opens to allow blood to flow forward. After contraction, the aortic valve closes to prevent blood from flowing back into the left ventricle. This ensures that blood only flows in one direction, from the left ventricle to the rest of the body.

The heart ejects oxygenated blood through the aorta, which is the largest artery in the body. The aorta carries oxygen-rich blood from the left ventricle of the heart to the rest of the body, supplying oxygen and nutrients to all the organs and tissues.

The pulmonary valve prevents backflow of blood into the right ventricle. It is located between the right ventricle and the pulmonary artery. When the right ventricle contracts, the pulmonary valve opens, allowing blood to be pumped into the pulmonary artery and then to the lungs. Once the ventricle relaxes, the pulmonary valve closes to prevent blood from flowing back into the ventricle. This ensures that blood flows in one direction, from the heart to the lungs, without any backflow.

The left atrium receives blood from the pulmonary veins, which carry oxygenated blood from the lungs. However, the given answer states that the blood entering the left atrium is deoxygenated. This contradicts the normal physiological process and is incorrect.

The correct answer is the coronary sinus. The coronary sinus is responsible for draining venous blood from the heart muscle itself, rather than from the lower portion of the body. The superior vena cava drains blood from the upper body, while the inferior vena cava drains blood from the lower body. Therefore, neither of these options is the correct answer in this case.

The trabeculae carnae are rounded or irregular muscular columns that project from the inner surface of the right and left ventricles of the heart.