Question

The urination becomes voluntary when the urine reaches in the
A. Pelvis
B. Urinary bladder
C. Ureter
D. Urethra

Answer 1

Urination is also called micturition. The process of excreting urine from the urinary bladder. Nerve centers for the control of urination lie in the spinal cord. Here both voluntary and involuntary muscles are involved.

Complete answer:
Urinary bladder is a storage reservoir for urine – a liquid containing waste products which are excreted from the bloodstream by the kidneys. Urinary bladder can accumulate about 300 – 400 milliliters, here the sensations are felt to empty the bladder. The bladder fills slowly which adapts to the pressure and increases the volume. After getting enough pressure, the neck of the bladder and opening to the urethra relax and the contents are removed or emptied and the bladder empties completely. The ability to start and stop the flow of urine depends on muscles of the pelvic floor, the abdominal wall, and the diaphragm and they apply pressure to the wall of the urinary bladder in which urination becomes voluntary.
-Pelvis: The pelvis is located between the abdomen and the legs. It provides for the intestine and also bladder and reproductive organs.
-Ureter: The tube that carries urine from the kidney to the urinary bladder. The muscles of ureter walls tighten and relax the force of urine down away from the kidneys.
-Urethra: It connects the duct of deferens in males for the ejaculation of sperms. It also transports the urine from the bladder to the tip of the penis which allows the bladder to empty while urinating.

Hence, the correct answer is Option D.

Note: The internal urethral sphincter and the external urethral sphincter are helpful to control the flow of urine. The internal sphincter is involuntary which allows urine to pass. The external sphincter is voluntary. It must be relaxed for urination to occur.