Consider the following statements? (a) Before birth, foramen ovale allows the blood to pass from right atrium to left atrium , thus bypassing the pulmonary circulation , (b) Heart is protected by a double walled pericardium , (c) The muscle fibres present in heart are different from smooth muscles in being mesodermal in origin , (d) Nodal tissues like AVN, SAN are specialised neural tissues which are distributed in heart. How many among the statements mentioned above are correct?

Options

A. Two
B. Three
C. One
D. Four

Answer

To determine how many of the statements provided are correct, let's analyze each one step by step:

1. **Statement (a)**: "Before birth, foramen ovale allows the blood to pass from right atrium to left atrium, thus bypassing the pulmonary circulation."
- **Analysis**: This statement is correct. The foramen ovale is an opening in the septum between the right and left atria that allows blood to flow directly from the right atrium to the left atrium in fetal circulation, bypassing the lungs which are not yet functional.
- **Conclusion**: True

2. **Statement (b)**: "Heart is protected by a double-walled pericardium."
- **Analysis**: This statement is also correct. The heart is enclosed in a double-walled sac called the pericardium, which consists of an outer fibrous layer and an inner serous layer that provides protection and reduces friction during heartbeats.
- **Conclusion**: True

3. **Statement (c)**: "The muscle fibres present in heart are different from smooth muscles in being mesodermal in origin."
- **Analysis**: This statement is incorrect. While cardiac muscle fibers are indeed different from smooth muscle fibers, they are both derived from mesoderm. Therefore, the statement's claim that they are different in being mesodermal in origin is misleading.
- **Conclusion**: False

4. **Statement (d)**: "Nodal tissues like AVN, SAN are specialised neural tissues which are distributed in heart."
- **Analysis**: This statement is correct. The sinoatrial node (SAN) and atrioventricular node (AVN) are specialized tissues that function as pacemakers in the heart, controlling the heart's rhythm. They are not neural tissues but are often referred to as nodal tissues due to their role in electrical conduction.
- **Conclusion**: True

Now, let's summarize the correctness of each statement:
- Statement (a): True
- Statement (b): True
- Statement (c): False
- Statement (d): True

**Final Count of Correct Statements**: 3 statements are correct (a, b, and d).

**Answer**: 3 statements are correct.

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