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Identify the correct sequence of the car...

Identify the correct sequence of the cardiac cycle.
(i) Blood through the pulmonary vein and vena cava enters in left and right atria respectively.
(ii) AVN generates action potential for the ventricles.
(iii) SAN bring about atrial systole .
(iv) Ventricular systole pushes blood away from the heart .

A

`i rarriirarriiirarr iv`

B

`irarriiirarriirarriv`

C

`iiirarr iirarriv`

D

`iiirarrivrarrii rarri`

Text Solution

AI Generated Solution

The correct Answer is:
To identify the correct sequence of the cardiac cycle, we need to analyze the steps involved in the functioning of the heart during this cycle. Here’s a step-by-step breakdown of the process: ### Step 1: Blood Enters the Atria - The cardiac cycle begins with the heart in a relaxed state, known as diastole. During this time, blood flows into the heart through the pulmonary veins into the left atrium and through the vena cava into the right atrium. This corresponds to statement (i). ### Step 2: Atrial Systole - The sinoatrial node (SAN), which is the heart's natural pacemaker, generates an action potential. This electrical impulse causes the atria to contract, pushing blood into the ventricles. This corresponds to statement (iii). ### Step 3: Action Potential to Ventricles - The action potential generated by the SAN is transmitted to the atrioventricular node (AVN), which then sends the signal to the ventricles. This action potential leads to ventricular contraction. This corresponds to statement (ii). ### Step 4: Ventricular Systole - As the ventricles contract (ventricular systole), they push blood out of the heart through the pulmonary artery and aorta. This corresponds to statement (iv). ### Correct Sequence Based on the breakdown above, the correct sequence of the cardiac cycle is: 1. (i) Blood through the pulmonary vein and vena cava enters in left and right atria respectively. 2. (iii) SAN brings about atrial systole. 3. (ii) AVN generates action potential for the ventricles. 4. (iv) Ventricular systole pushes blood away from the heart. ### Final Answer The correct order is: (i) → (iii) → (ii) → (iv).
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