Multi-unit smooth muscle is seen in

Options

A. Stomach
B. Intestine
C. Urinary bladder
D. Large blood vessel

Answer

**Step-by-Step Solution:**

1. **Understand the Types of Smooth Muscle:**
- Smooth muscles are classified into two types: single-unit smooth muscle and multi-unit smooth muscle.
- Single-unit smooth muscle fibers are interconnected and contract as a single unit, while multi-unit smooth muscle fibers are independent and can contract separately.

2. **Identify the Characteristics of Multi-Unit Smooth Muscle:**
- Multi-unit smooth muscle fibers are composed of independent muscle fibers.
- Each fiber can contract independently, allowing for more precise control of muscle contractions.

3. **Locate Where Multi-Unit Smooth Muscle is Found:**
- Multi-unit smooth muscles are found in specific locations in the body:
- Erector pili muscles (associated with hair follicles)
- Ciliary muscles (which control the lens shape in the eye)
- Iris muscles (which control the size of the pupil)
- Muscles in the walls of large blood vessels

4. **Evaluate the Options Given in the Question:**
- The question asks where multi-unit smooth muscle is seen.
- Based on the identified locations, the correct answer would be the organs that contain multi-unit smooth muscle.

5. **Conclude with the Correct Answer:**
- The correct answer is that multi-unit smooth muscle is found in the erector pili muscles, ciliary muscles, iris muscles, and muscles of large blood vessels.

**Final Answer:**
Multi-unit smooth muscle is seen in the erector pili muscles, ciliary muscles, iris muscles, and muscles of large blood vessels.

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