Question

Which one is not supplied exclusively with involuntary muscles?

• A. Iris
• B. Gland ducts
• C. Urethra
• D. Coats of blood vessels

Answer 1

The correct option is C Urethra

Iris is supplied by involuntary muscles which contract or relax in response to photo stimuli. Gland ducts have muscles in their walls and in the form of sphincters which are involuntary. Coats of blood vessels also have a muscle layer sandwiched between two other layers. Urethra has two sphincters of which one is involuntary and one is voluntary. Hence, urethra is not exclusively supplied with involuntary muscles.