Question

Blood pressure in the mammalian aorta is maximum during

• A. systole of the left ventricle
• B. diastole of the right atrium
• C. systole of the left atrium
• D. diastole of the right ventricle.

Answer 1

The Correct Option is A

To determine when the blood pressure in the mammalian aorta is at its maximum, we need to understand the phases of the heart's cardiac cycle.

The heart undergoes a series of rhythmic contractions and relaxations known as the cardiac cycle, which includes two main phases:

1. Systole: This is the phase of contraction. The heart's chambers contract, forcing blood out. The left ventricle's systole is particularly significant for systemic blood circulation.
2. Diastole: This is the phase of relaxation. The heart's chambers relax, allowing them to fill with blood.

Now, let's evaluate the options given:

• Systole of the left ventricle: During this phase, the left ventricle contracts and pumps blood into the aorta. This is when the blood pressure in the aorta is at its highest, as the force exerted by the left ventricle is maximum to propel blood throughout the body.
• Diastole of the right atrium: During this phase, the right atrium is relaxed and filling with blood, which does not affect the blood pressure in the aorta significantly.
• Systole of the left atrium: This is when the left atrium contracts to push blood into the left ventricle. While this contributes to filling the ventricle, it does not produce the peak pressure in the aorta.
• Diastole of the right ventricle: This phase involves the relaxation of the right ventricle, during which it fills with blood. It is unrelated to aortic pressure.

From the options, it is clear that the blood pressure in the mammalian aorta is maximum during the systole of the left ventricle, as this is when the heart exerts the highest force to circulate blood throughout the body.

Therefore, the correct answer is: systole of the left ventricle.