Which of the following statement is CORRECT ?
I. Heart, the mesodermally derived organ, is situated in the thoracic cavity, in between the two lungs , slightly tilted to the left.
II. During joint diastole , tricuspid and bicuspid valves are open and the semilunar values are closed.
III. The first heart sound (lub) is associated with the closure of the tricuspid and biscuspid valves whereas the second heart sound (dub) is associated with the closure of the semilunar valves .
IV. Neural signals through the sympathetic nerves can increases the rate of hearbeat, the strength of ventricular contraction and thereby the cardiac output.

Options

A. I,II , III and IV
B. I,III and IV
C. II, III and IV
D. I,II and III

Answer

To determine which of the statements about the heart is correct, let's analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement I**: "Heart, the mesodermally derived organ, is situated in the thoracic cavity, in between the two lungs, slightly tilted to the left."
- The heart is indeed derived from the mesoderm, and it is located in the thoracic cavity between the lungs, tilted slightly to the left.
- **Conclusion**: This statement is **correct**.

**Hint**: Remember that the heart's position is crucial for its function and is a key anatomical fact.

2. **Statement II**: "During joint diastole, tricuspid and bicuspid valves are open and the semilunar valves are closed."
- During joint diastole, the heart is in a relaxed state, allowing blood to flow from the atria to the ventricles. The tricuspid valve (between right atrium and right ventricle) and bicuspid valve (between left atrium and left ventricle) are indeed open, while the semilunar valves (aortic and pulmonary) are closed.
- **Conclusion**: This statement is **correct**.

**Hint**: Joint diastole is a phase of relaxation, allowing for filling of the heart chambers.

3. **Statement III**: "The first heart sound (lub) is associated with the closure of the tricuspid and bicuspid valves whereas the second heart sound (dub) is associated with the closure of the semilunar valves."
- The first heart sound (lub) is indeed produced by the closure of the atrioventricular valves (tricuspid and bicuspid), and the second heart sound (dub) is produced by the closure of the semilunar valves.
- **Conclusion**: This statement is **correct**.

**Hint**: The heart sounds are important indicators of valve function and timing during the cardiac cycle.

4. **Statement IV**: "Neural signals through the sympathetic nerves can increase the rate of heartbeat, the strength of ventricular contraction and thereby the cardiac output."
- The sympathetic nervous system does indeed increase heart rate and the strength of ventricular contractions, leading to an increase in cardiac output.
- **Conclusion**: This statement is **correct**.

**Hint**: The sympathetic nervous system plays a key role in the 'fight or flight' response, affecting heart function.

### Final Conclusion:
All four statements (I, II, III, and IV) are correct. Therefore, the correct answer is that all statements are correct.