Akshay’s father had a tumour in his prostate gland. His doctor advised him to get it removed surgically. One side effect of the surgery was incontinence of urine, i.e., leakage of urine from the urinary bladder.
Name the structure that regulates the flow of urine from the urinary bladder into the urethra.
Topic: Urethral sphincter
Answer
The URETHRAL SPHINCTER (the internal urethral sphincter).
A sphincter is a ring of muscle that closes a passage. The urethral sphincter sits at the neck of the bladder and stays contracted, holding urine in, until it is voluntarily relaxed.
This answers the case in the question: prostate surgery close to the sphincter can damage it, and a sphincter that cannot stay closed means urine leaks — incontinence.
The sequence to keep straight: kidney → ureter → urinary bladder → (urethral sphincter) → urethra → outside. Note the spelling difference that costs marks every year: URETER carries urine from kidney to bladder; URETHRA carries it from bladder to outside.