Question

In mammals, the opening of post caval in the right auricle is guarded by
(a) Mitral valve
(b) The basius valve
(c) Eustachius valve
(d) Bicuspid valve

Answer 1

The human heart consists of four chambers, two atria, and two ventricles. Before leaving each chamber the blood has to pass through a valve that restricts the backflow of blood.

Complete answer:
In mammals, the opening of the post caval in the right auricle is guarded by the eustachian valve.
Eustachius valve is the valve of the inferior Vena cava and is the valve of a vein that is the Venus valve. This valve lies at the junction of the inferior Vena cava and right atrium. This valve guides the opening of the Vena cava and allows the blood to enter into the right atrium. This valve also helps in directing the flow of oxygenated blood through the right atrium into the left atrium and away from the right ventricle. Both the superior and inferior Vena cava brings the deoxygenated blood from the body to the heart and from the heart, these are directed towards the lungs for the purification of blood.

Additional Information: -The valves are located on each end of the two ventricles that is the lower chamber of the heart. They allow the blood to flow from one ventricle to the other without the backward flowers.
-The four types of valves present in the heart are the tricuspid valve, pulmonary valve, mitral valve, and aortic valve.
-Mitral valve: This valve consists of two cups and is located between the left atrium and left ventricle. It allows the flow of blood from the lungs to the left atrium.
-Tricuspid valve: These are also called atrioventricular valves located between the right atrium and the right ventricle. It consists of three cups that is why it is called the tricuspid valve which prevents the backflow of blood from the right ventricle to the right atrium.
-Pulmonary valve: These are also called semilunar valves having three cups. The pulmonary valve lies between the junction of the right ventricle and the pulmonary artery.
-Aortic valve: These valves are located between the left ventricle and the aorta, consisting of three cups. These valves direct the blood to flow from the left ventricle to the whole body through the aorta.
So, the correct answer is 'Eustachian valve'.

Note: -These valves are a part of the inferior Vena cava that is left after a great part has been used.
-These walls do not have any specific function in a normal adult.
-Normally valves are having three flaps except the mitral valve which is having only two flaps.
-Eustachius valve is the valve of a vein that is the Venus valve.