What are the functions of chordae tendineae and papillary muscle?

Chordae tendineae and papillary muscles play crucial roles in the proper functioning of the heart, particularly in the mitral and tricuspid valves. Here are their functions:

Chordae Tendineae:

1. Valve Attachment: Chordae tendineae are thin, string-like structures that connect the edges of the mitral and tricuspid valve leaflets to the papillary muscles. They act as strong, flexible tethers that anchor the leaflets in place.

2. Prevention of Valve Prolapse: During ventricular contraction (systole), the pressure inside the ventricles increases significantly. Chordae tendineae prevent the valve leaflets from being pushed back (prolapsing) into the atria due to this increased pressure.

3. Proper Valve Closure: When the ventricles relax (diastole), the pressure inside decreases. The chordae tendineae prevent the leaflets from bulging excessively into the ventricles, ensuring proper valve closure.

Papillary Muscles:

1. Location: Papillary muscles are small, cone-shaped muscles located on the inner walls of the ventricles. They contract simultaneously with the ventricular myocardium during systole.

2. Connection to Chordae Tendineae: The papillary muscles are indirectly connected to the valve leaflets through the chordae tendineae. The contraction of the papillary muscles creates tension on the chordae tendineae, preventing valve prolapse.

3. Valve Opening: During ventricular relaxation, the papillary muscles relax, reducing tension on the chordae tendineae. This allows the valve leaflets to open freely, enabling blood flow from the atria to the ventricles.

4. Prevention of Backflow: When the ventricles contract, the papillary muscles contract, pulling the chordae tendineae and closing the valve leaflets firmly. This prevents backflow of blood from the ventricles into the atria.

Together, the chordae tendineae and papillary muscles ensure the proper opening and closing of the mitral and tricuspid valves. They prevent valve prolapse and backflow, facilitating efficient blood flow within the heart chambers. Dysfunction or damage to these structures can lead to valvular regurgitation or stenosis, requiring medical intervention.