Question

Describe the process of Urination in the Urinary Bladder. The Urinary Bladder is filling with Urine and the Micturition Reflex (Urination) starts… what starts the process, how the nervous system is involved, what part of the spine is involved, how does the bladder respond, what does the bladder do, how/when the sphincters are involved, etc?

Answer 1

The process of urination in the urinary bladder involves the micturition reflex, which is controlled by the nervous system. As the bladder fills with urine, the detrusor muscle contracts and the internal urethral sphincter relaxes. The external urethral sphincter can be voluntarily controlled to maintain urinary continence.

Step-by-step explanation:

The process of urination in the urinary bladder involves various components of the nervous system. As the bladder fills with urine, stretch receptors in the bladder wall send signals to the sacral region of the spinal cord. These signals generate a spinal reflex, known as the micturition reflex, that causes the detrusor muscle in the bladder wall to contract and the internal urethral sphincter to relax.

At the same time, the spinal cord inhibits the somatic motor neurons, resulting in the relaxation of the skeletal muscle of the external urethral sphincter. This allows the urine to flow out of the bladder and the body through the urethra.

The process of urination can be voluntarily controlled by consciously preventing the relaxation of the external urethral sphincter to maintain urinary continence. However, as the bladder fills and subsequent urges to urinate become stronger, voluntary control may fail, resulting in bladder emptying.