Question

multiple choice question

what is the action of the bulbospongiosus in males?

aids in urine retention; anchors other pelvic muscles
constricts urethra; erection of penis; expulsion of semen
compresses anal canal and reinforces external sphincters
retains feces in rectum until voluntarily voided

Explanation:

Identify the muscle and its location

The question asks for the action of the bulbospongiosus muscle in males. This muscle is located in the perineum, covering the bulb of the penis.

Analyze the physiological function

In males, contraction of the bulbospongiosus muscle compresses the bulb of the penis and the bulbous portion of the urethra. This action helps empty the urethra of residual urine or semen, assists in maintaining erection by impeding venous return, and aids in the forceful expulsion of semen during ejaculation.

Evaluate the given options

• Option 1: "Aids in urine retention; anchors other pelvic muscles" — Incorrect. This does not describe the primary active role of the bulbospongiosus.
• Option 2: "Constricts urethra; erection of penis; expulsion of semen" — Correct. This matches the physiological actions of compressing the urethra, assisting in erection, and ejecting semen.
• Option 3: "Compresses anal canal and reinforces external sphincters" — Incorrect. This describes the external anal sphincter.
• Option 4: "Retains feces in rectum until voluntarily voided" — Incorrect. This is the function of the internal and external anal sphincters.

Answer:

• Aids in urine retention; anchors other pelvic muscles
• Constricts urethra; erection of penis; expulsion of semen (Correct answer)
• Compresses anal canal and reinforces external sphincters
• Retains feces in rectum until voluntarily voided