Go through the following statements
(i) The inner surface of atria have got transverse muscular ridges called papillary muscles.
(ii) Chordae tendinae are special fibrous cords attached to the AV valves and prevent them from collapsing back into the atria during powerful vantricular contraction
(iii) The neurogenic heart stops functioning immidiately after removal from the body.
(iv) The conduction of cardiac impulse is slowest in the A.V. node.
Which of these are correct ?

Options

A. (i), (ii) & (iii)
B. (ii) , (iii) & (iv)
C. (i) & (iii)
D. (ii) & (iv)

Explanation

To determine which statements are correct, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i)**: "The inner surface of atria have got transverse muscular ridges called papillary muscles."
- **Analysis**: Papillary muscles are not found in the atria; they are located in the ventricles. The inner surface of the atria has pectinate muscles, not papillary muscles.
- **Conclusion**: This statement is **incorrect**.

2. **Statement (ii)**: "Chordae tendinae are special fibrous cords attached to the AV valves and prevent them from collapsing back into the atria during powerful ventricular contraction."
- **Analysis**: Chordae tendinae do indeed attach to the atrioventricular (AV) valves (mitral and tricuspid) and prevent them from inverting during ventricular contraction, ensuring proper blood flow direction.
- **Conclusion**: This statement is **correct**.

3. **Statement (iii)**: "The neurogenic heart stops functioning immediately after removal from the body."
- **Analysis**: Neurogenic hearts, found in lower invertebrates (like cockroaches), do stop functioning immediately when removed from the body because they rely on the nervous system for stimulation.
- **Conclusion**: This statement is **correct**.

4. **Statement (iv)**: "The conduction of cardiac impulse is slowest in the A.V. node."
- **Analysis**: The A.V. node is known for its slow conduction of electrical impulses, which allows time for the atria to contract and fill the ventricles before they contract.
- **Conclusion**: This statement is **correct**.

### Final Summary:
- **Correct Statements**: (ii), (iii), and (iv) are correct.
- **Incorrect Statement**: (i) is incorrect.

Thus, the correct answer is **(ii), (iii), and (iv)**.