Define micturition and describe the micturition reflex.

Verified step by step guidance

1. Step 1: Define micturition as the process of expelling urine from the urinary bladder through the urethra to the outside of the body. It is commonly known as urination.
2. Step 2: Explain that the micturition reflex is a spinal cord reflex that controls the emptying of the bladder when it becomes full.
3. Step 3: Describe how stretch receptors in the bladder wall detect the increasing volume of urine, sending afferent signals via the pelvic nerves to the sacral region of the spinal cord.
4. Step 4: Outline that the spinal cord processes these signals and sends efferent impulses back to the detrusor muscle of the bladder, causing it to contract, and to the internal urethral sphincter, causing it to relax.
5. Step 5: Mention that voluntary control involves the external urethral sphincter, which is controlled by somatic motor neurons, allowing conscious initiation or delay of micturition.

Key Concepts

Micturition

Micturition is the physiological process of expelling urine from the urinary bladder through the urethra. It involves coordinated contraction of the bladder muscles and relaxation of the urinary sphincters, allowing urine to be voided from the body.

Micturition Reflex

The micturition reflex is a neural circuit that controls bladder emptying. It is initiated when stretch receptors in the bladder wall detect fullness, sending signals to the spinal cord and brain, which then coordinate detrusor muscle contraction and sphincter relaxation to trigger urination.

Neural Control of Micturition

Micturition is regulated by both autonomic and somatic nervous systems. Parasympathetic nerves stimulate bladder contraction, sympathetic nerves maintain bladder relaxation, and somatic nerves control the external urethral sphincter, allowing voluntary control over urination.