Which is true of contractile tissue of sphincter ?
1. Mesodermal 2. Contain stretch receptors
3.Rhythmicity 4 . Indefatigible

Options

A. All the four
B. Only 1 ,2 and 3
C. Only 1 , 2 and 4
D. Only 1, 3 and 4.

Answer

To determine which statements are true regarding the contractile tissue of sphincters, we will analyze each option step by step.

### Step 1: Analyze Option 1 - Mesodermal
- Contractile tissues, including those found in sphincters, originate from the mesoderm germ layer during embryonic development. Therefore, this statement is **true**.

### Step 2: Analyze Option 2 - Contains Stretch Receptors
- Sphincters, which are circular muscles, do indeed contain stretch receptors. These receptors help in sensing the degree of stretch and play a role in the regulation of the contraction of the sphincter. Thus, this statement is also **true**.

### Step 3: Analyze Option 3 - Rhythmicity
- While some contractile tissues exhibit rhythmic contractions (like cardiac muscle), sphincters typically do not exhibit rhythmicity in the same way. They contract in response to specific stimuli rather than in a rhythmic pattern. Therefore, this statement is **false**.

### Step 4: Analyze Option 4 - Indefatigible
- Indefatigible means not easily fatigued. However, sphincter muscles can become fatigued with prolonged use or continuous contraction. Hence, this statement is **false**.

### Conclusion
Based on the analysis:
- **True statements**: 1 (Mesodermal), 2 (Contains stretch receptors)
- **False statements**: 3 (Rhythmicity), 4 (Indefatigible)

Thus, the correct answer is **only 1 and 2 are true**.

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