Answer:
Overall, the response to the stretching of the urinary bladder wall during the micturition reflex involves the contraction of bladder muscles, relaxation of the internal sphincter, and voluntary control of the external sphincter and pelvic floor muscles. This coordinated response allows for the emptying of the bladder and the elimination of urine from the body.
Step-by-step explanation:
When the urinary bladder wall stretches during the micturition reflex, several responses occur to allow for the emptying of the bladder. Here is a step-by-step explanation of the response:
1. Stretch receptors in the urinary bladder wall detect the increase in volume as the bladder fills with urine.
2. These stretch receptors send signals to the spinal cord, which then transmit the information to the brain.
3. In response, the brain initiates the micturition reflex, also known as the urination reflex.
4. The micturition reflex involves the contraction of the bladder muscles, known as the detrusor muscles, which help push urine out of the bladder.
5. At the same time, the internal sphincter, which is a circular muscle at the base of the bladder, relaxes to allow urine to flow from the bladder into the urethra.
6. The external sphincter, a voluntary muscle located just below the internal sphincter, can be consciously controlled to either open or close the urethra.
7. When the external sphincter is voluntarily relaxed, urine can pass through the urethra and out of the body.
8. During this process, the muscles of the pelvic floor also relax, further aiding in the expulsion of urine.