Why are valves present in heart and veins?
Answers
Answer :-
Valves are present in the heart and veins to prevent the backflow of the blood when the ventricles relax. The left and right atria are connected to ventricles with two openings called left and right atrioventricular apertures. These two apertures are fitted with to valves. The right atrioventricular valve has three cusps so it is called tricuspid valve and the left one has two cusps so it is called bicuspid valve or mitral valve. These valves can open towards the ventricles only. They withstand high pressure and do not open to reverse direction. The exits of aorta and pulmonary trunk are fitted with two outwardly directed valves. These are known as aortic valve and pulmonary valve respectively.
Valves :
Valves are present in veins to separate each of the chambers so that there is no mixing of blood. They allow blood to flow only in one direction.
These valves are actual flaps that are located on each end of the two ventricles (lower chambers of the heart). They act as one-way inlets of blood on one side of a ventricle and one-way outlets of blood on the other side of a ventricle.
The heart has 4 valves:
- The mitral valve and tricuspid valve, which control blood flow from the atria to the ventricles
- The mitral valve and tricuspid valve, which control blood flow from the atria to the ventriclesThe aortic valve and pulmonary valve, which control blood flow out of the ventricles
