Which one of the following statements is correct?a)The atrio-ventricu...
Option (C) is the correct answer because during joint diastole, blood moves freely from atrium to ventricle as atrioventricular valve remain open during joint diastole.
Option (D) is incorrect because decrease in ventricular pressure, during ventricular diastole closes semilunar valves to produce ‘dub’ heart sound.
Option (A) is incorrect because SA node generates action potential to stimulate atrial contraction.
Option (B) is incorrect because bicuspid and tricuspid valves open due to pressure exerted by blood present in atria and decrease in pressure in ventricles during ventricular diastole.
Which one of the following statements is correct?a)The atrio-ventricu...
Blood moves freely from the atrium to the ventricle during joint diastole.
During the cardiac cycle, the heart undergoes a series of coordinated contractions and relaxations that allow for efficient pumping of blood. One important phase of the cardiac cycle is diastole, which involves relaxation of the heart muscle and filling of the chambers with blood.
During diastole, both the atria and ventricles are in a relaxed state. In this state, the atria are able to fill with blood from the veins, while the ventricles are able to fill with blood from the atria.
The statement that blood moves freely from the atrium to the ventricle during joint diastole is correct. This is due to the following factors:
1. Atrial relaxation: During diastole, the atria are in a relaxed state. This relaxation allows the atria to expand and fill with blood that is returning from the veins. The pressure within the atria is relatively low, which facilitates the flow of blood into the ventricles.
2. Open atrioventricular (AV) valves: The tricuspid valve, located between the right atrium and the right ventricle, and the bicuspid (or mitral) valve, located between the left atrium and the left ventricle, are open during diastole. These valves consist of flaps of tissue that prevent the backflow of blood. When the atria are relaxed, the AV valves remain open, allowing blood to flow freely from the atria to the ventricles.
3. Pressure difference: The pressure within the atria is slightly higher than the pressure within the ventricles during diastole. This pressure difference also contributes to the movement of blood from the atria to the ventricles.
It is important to note that during diastole, the semilunar valves, which are located at the entrances of the major arteries leaving the heart, are closed. This prevents the backflow of blood from the arteries into the ventricles. The closure of the semilunar valves is facilitated by the higher pressure within the ventricles compared to the arteries.
In summary, during joint diastole, blood moves freely from the atrium to the ventricle due to atrial relaxation, open AV valves, and the pressure difference between the atria and ventricles.
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