Chordae tendineae

Options

A. Increase area of ventricle
B. Prevent pushing of auriculoventricular valve into auricles
C. Keep auricles stretched
D. Direct flow of blood into truncus arteriosus

Answer

### Step-by-Step Solution:

1. **Understanding Chordae Tendineae**: The chordae tendineae are fibrous cords that connect the papillary muscles to the heart valves, specifically the atrioventricular (AV) valves, which include the tricuspid and bicuspid (mitral) valves.

**Hint**: Remember that chordae tendineae are crucial for the functioning of the heart valves.

2. **Location in the Heart**: These structures are found in the ventricles of the heart, where they play a vital role during the cardiac cycle.

**Hint**: Identify where the chordae tendineae are located to understand their function better.

3. **Function During Ventricular Systole**: During ventricular systole (the contraction phase of the ventricles), the chordae tendineae prevent the AV valves from being pushed back into the atria (auricles). This ensures that blood flows in the correct direction and does not backtrack.

**Hint**: Focus on the role of chordae tendineae during heart contractions.

4. **Identifying the Correct Answer**: The question provides multiple options regarding the function of chordae tendineae. The correct answer is that they prevent the pushing of the AV valves into the auricles during ventricular contraction.

**Hint**: Compare each option with the known functions of chordae tendineae to find the correct one.

5. **Eliminating Incorrect Options**: The other options, such as increasing the area of the ventricles or keeping auricles stretched, do not accurately describe the function of chordae tendineae. Additionally, the mention of truncus arteriosus is irrelevant to the function of chordae tendineae.

**Hint**: Analyze each option critically to determine which ones do not relate to the function of chordae tendineae.

### Final Answer:
The correct answer is that the chordae tendineae prevent the pushing of the AV valves into the auricles during ventricular contraction.