When the semilunar valves are open, which of the following are occurring? (a) 2, 3, 5, 6, (b) 1, 2, 3, 7, (c) 1, 3, 5, 6, (d) 2, 4, 5, 7.
_____(1) coronary arteries fill
_____(2) AV valves are closed
_____(3) ventricles are in systole
_____(4) ventricles are in diastole
_____(5) blood enters aorta
_____(6) blood enters pulmonary arteries
_____(7) atria contract
To determine:
The correct occurrence of sequences if semilunar valves are open
(a) 2, 3, 5, 6, (b) 1, 2, 3, 7, (c) 1, 3, 5, 6, (d) 2, 4, 5, 7
____ (1) coronary arteries fill
____ (2) AV valves are closed
____ (3) ventricles are in systole
____ (4) ventricles are in diastole
____ (5) blood enters aorta
____ (6) blood enters pulmonary arteries
____ (7) atria contract
Answer to Problem 1MC
Solution:
(a) 2, 3, 5, 6: The events that occur when the semilunar valves are open are listed as follows:
1. The closing of atrioventricular valves.
2. The ventricles are in the systolic stage.
3. The blood enters the aorta.
4. The blood enters the pulmonary arteries.
Explanation of Solution
The semilunar valve is situated between the left ventricle and aorta of the heart. The opening of the semilunar valves marks the systolic stage. The atrioventricular valves at this stage are closed in order to prevent the backflow of the blood. The blood is pumped to the aorta and the pulmonary artery to distribute it to the different parts of the body.
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