Blood enters the heart because muscles of thea)Ventricles contractb)Ventricles relaxc)Atria contractd)Atria relaxCorrect answer is option 'D'. Can you explain this answer?

Question

Answer

Atrial diastole is characterized by the relaxation of the atrial muscles. During this stage, the blood enters into the atria, as the volume of the blood in the atria increases the pressure within it decreases.
So, the correct answer is option D.

Answer

Human heart consists of 2 atria nd 2 ventrical. On upper side of right, there is right atria nd bottom of right, there is right ventrical. same is on the left side as well. so when the blood is transported from diffrent parts of the body to our heart (by veins), the veins r in a contracted position as they contains blood in it. On contrary, as the veins relaxes, the blood contained in the veins gets poured in the right atria of heart. so as result, when the veins gets relaxed, the whole blood in the veins which is in the contracted form gets inside the heart. I hope u understood :)

Answer

Answer:

Blood enters the heart because of the relaxation of the atria. The correct answer is option 'D' - Atria relax.

Explanation:

In the human circulatory system, the heart acts as a pump that circulates blood throughout the body. It consists of four chambers - two atria (left and right) and two ventricles (left and right). The atria are the upper chambers, while the ventricles are the lower chambers.

Function of Atria:
The main function of the atria is to receive blood from the body and lungs. The right atrium receives deoxygenated blood from the body through the superior and inferior vena cava, while the left atrium receives oxygenated blood from the lungs through the pulmonary veins.

Function of Ventricles:
The ventricles are responsible for pumping blood out of the heart. The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery, while the left ventricle pumps oxygenated blood to the rest of the body through the aorta.

The Cardiac Cycle:
The cardiac cycle consists of two phases - diastole and systole. Diastole is the relaxation phase, while systole is the contraction phase.

Atria Relaxation:
During the diastole phase, the atria relax and fill with blood. This relaxation allows the atria to expand and create a low-pressure area. As a result, blood from the body and lungs flows passively into the atria due to the pressure difference.

Ventricles Contraction:
Once the atria are filled with blood, the ventricles contract during systole. This contraction increases the pressure inside the ventricles, causing the atrioventricular valves (mitral and tricuspid valves) to close. The closure of these valves prevents blood from flowing back into the atria.

Ejection of Blood:
As the ventricles continue to contract, the pressure inside them exceeds the pressure in the pulmonary artery and aorta. This causes the semilunar valves (pulmonary and aortic valves) to open, allowing blood to be ejected from the ventricles into the respective arteries.

Conclusion:
In summary, blood enters the heart because of the relaxation of the atria during the diastole phase. This relaxation creates a low-pressure area, allowing blood to flow passively into the atria from the body and lungs.

Answer

If atria relax then the blood present in atrium enters into ventricle through valve then blood enters into atria hope it will help..

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