During the micturition reflex, which statement is true?

During the micturition reflex, which statement is true?

• A. Stretch receptors in the bladder wall send impulses to the thoracic cord.
• B. Parasympathetic motor neurons that control the detrusor muscle become inactive.
• C. The internal sphincter is subconsciously relaxed.
• D. The external sphincter is always contracted.

Answer: (C)

During the micturition reflex, the process of urination involves a complex coordination of nervous system responses. The statement about the internal sphincter being subconsciously relaxed is accurate. When the bladder fills with urine, stretch receptors in the bladder wall are activated and send signals to the spinal cord, specifically to sacral segments, which are part of the parasympathetic nervous system. This triggers the contraction of the detrusor muscle (the muscle of the bladder) and helps to relax the internal sphincter, allowing urine to flow into the urethra. While the external sphincter, which is under voluntary control, can remain contracted to prevent urination until the individual is ready, the internal sphincter is relaxed reflexively and unconsciously during this process. This coordination ensures that urination can occur smoothly when appropriately initiated by the individual. In the other statements, the inclination to send impulses to the thoracic cord is incorrect since the stretch receptors communicate with the sacral spinal cord. The idea that the parasympathetic motor neurons controlling the detrusor muscle become inactive does not hold, as these neurons must be active for the bladder to contract. Lastly, maintaining the external sphincter in a constant state

During the micturition reflex, the process of urination involves a complex coordination of nervous system responses. The statement about the internal sphincter being subconsciously relaxed is accurate.

When the bladder fills with urine, stretch receptors in the bladder wall are activated and send signals to the spinal cord, specifically to sacral segments, which are part of the parasympathetic nervous system. This triggers the contraction of the detrusor muscle (the muscle of the bladder) and helps to relax the internal sphincter, allowing urine to flow into the urethra.

While the external sphincter, which is under voluntary control, can remain contracted to prevent urination until the individual is ready, the internal sphincter is relaxed reflexively and unconsciously during this process. This coordination ensures that urination can occur smoothly when appropriately initiated by the individual.

In the other statements, the inclination to send impulses to the thoracic cord is incorrect since the stretch receptors communicate with the sacral spinal cord. The idea that the parasympathetic motor neurons controlling the detrusor muscle become inactive does not hold, as these neurons must be active for the bladder to contract. Lastly, maintaining the external sphincter in a constant state