Questions: A/an is the structure from which chordae tendineae originate. Multiple Choice - pulmonary valve - aortic valve - interatrial septum - papillary muscle

The answer is the fourth one: papillary muscle.

Explanation for each option:

1. Pulmonary valve: This is a valve in the heart that controls blood flow from the right ventricle into the pulmonary arteries. It is not involved in the origin of chordae tendineae.

2. Aortic valve: This valve controls blood flow from the left ventricle into the aorta. Like the pulmonary valve, it does not have chordae tendineae attached to it.

3. Interatrial septum: This is the wall separating the left and right atria of the heart. It does not have any role in the origin of chordae tendineae.

4. Papillary muscle: These muscles are located in the ventricles of the heart and are attached to the chordae tendineae. They contract to prevent inversion or prolapse of the atrioventricular valves (mitral and tricuspid) during ventricular contraction. Therefore, the chordae tendineae originate from the papillary muscles.

In summary, the structure from which chordae tendineae originate is the papillary muscle.