Question

The urinary opening is known as
A. Urinary bladder
B. Ureter
C. Urethra
D. None of the above

Answer 1

Hint: It connects the urinary bladder to the body surface allowing urine to flow out. It also serves to discharge sperm in males.

Complete Answer:
- The excretory system in humans consists of a pair of kidneys, one pair of ureters, one urinary bladder, and one urethra. The kidneys produce urine by filtering out waste and extra blood water.
- The ureters are two thin tubes through which urine moves from the kidneys to reach the bladder. When the bladder is full, a person eliminates the waste through the urethra.
- The ureteral wall muscles continuously tighten and relax, forcing urine downward, away from the kidneys.
- The urinary bladder is a hollow, globular organ located in the pelvis that stores urine.
- Ligaments which are attached to other organs and the pelvic bones hold it in place. A healthy, normal bladder can hold up nearly half a litre of urine for two to five hours.
- The urethra is the opening through which urine moves from the bladder to the outside. The flow of urine through the urethra is controlled by muscles in the inner and outer urethral sphincter.
- The inner urethral sphincter consists of smooth muscle that involuntarily opens when the bladder reaches a certain distention level. The outer urethral sphincter consists of the skeletal muscle that can open or close to allow urine to pass through the urethra or delay urination.

Therefore, the correct answer is option C. i.e., Urethra.

Note: The urethra in females is short, just 3 to 4 cm (about 1.5 inches) long. The outer urethral orifice opens to the outside just before the vaginal opening. The urethra in males is much longer, about 20 cm (7 to 8 inches) in length. It functions to transport both urine and sperm.