Which of these statements about sphincters of urethra is CORRECT ?

Options

A. Internal urethral sphincter is made up to smooth muscles while external urethral sphincter is made up of striated muscles.
B. Internal urethral sphincter is made up to striated muscles while external urethral sphincter is made up of smooth muscles.
C. Both Internal and external urethral sphincter is made up to smooth muscles.
D. Both Internal and external urethral sphincter is made up to striated muscles.

Answer

To determine which statement about the sphincters of the urethra is correct, we need to analyze the characteristics of the internal and external urethral sphincters.

### Step-by-Step Solution:

1. **Understanding the Sphincters**:
- The urethra has two main sphincters: the internal urethral sphincter and the external urethral sphincter.

2. **Internal Urethral Sphincter**:
- The internal urethral sphincter is composed of smooth muscle. This muscle type is involuntary, meaning it is not under conscious control. It helps to maintain continence by constricting the urethra.

3. **External Urethral Sphincter**:
- The external urethral sphincter is composed of striated (skeletal) muscle. This muscle type is voluntary, allowing for conscious control over urination. It surrounds the urethra and can be contracted or relaxed at will.

4. **Evaluating the Statements**:
- Option 1 states that the internal urethral sphincter is made up of smooth muscles while the external urethral sphincter is made up of striated muscles. This statement is correct.
- Option 2 incorrectly states that the internal urethral sphincter is made up of striated muscles.
- Option 3 also incorrectly states that both sphincters are made up of smooth muscles.
- Option 4 is vague and does not specify the type of muscles, making it less precise than option 1.

5. **Conclusion**:
- The correct answer is Option 1: "Internal urethral sphincter is made up of smooth muscles while external urethral sphincter is made up of striated muscles."