Movement of which muscles can alter the pericardial space in cockroach ?

Options

A. Circular
B. Longitudinal
C. Alary
D. Ciliary

Answer

To answer the question regarding which muscles can alter the pericardial space in cockroaches, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Anatomy of the Cockroach Heart**:
- The cockroach heart consists of 13 chambers and is located in the dorsal part of the thorax and abdomen. It is covered by a protective sac known as the pericardium.

2. **Identify the Pericardial Space**:
- The pericardial space is the fluid-filled cavity between the two layers of the pericardium (the visceral and parietal layers). This space plays a crucial role in protecting the heart and allowing it to function effectively.

3. **Recognize the Role of Muscles in Blood Circulation**:
- In cockroaches, the movement of certain muscles is essential for blood circulation. The contraction and relaxation of these muscles help in pumping the blood through the heart chambers.

4. **Identify the Specific Muscles**:
- The muscles that are primarily responsible for altering the pericardial space and assisting in blood circulation are known as the **alary muscles**. These muscles are associated with the dorsal diaphragm and are located on either side of the cockroach heart.

5. **Explain the Function of Alary Muscles**:
- The alary muscles contract and relax alternately, which helps in changing the volume of the pericardial space. This action creates a pressure difference that aids in the movement of hemolymph (the insect equivalent of blood) through the heart chambers.

6. **Conclude with the Correct Answer**:
- Therefore, the movement of **alary muscles** can alter the pericardial space in cockroaches, making them the correct answer to the question.

### Final Answer:
The movement of **alary muscles** can alter the pericardial space in cockroaches.

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