Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The micturition reflex is the process by which the urinary bladder is emptied. It involves both involuntary and voluntary muscle contractions regulated by neural circuits.
5 Must Know Facts For Your Next Test
Micturition reflex is initiated when stretch receptors in the bladder wall detect a certain level of fullness, sending signals to the spinal cord.
The internal urethral sphincter, controlled by the autonomic nervous system, relaxes as part of this reflex.
The external urethral sphincter, controlled voluntarily via the somatic nervous system, must be consciously relaxed to complete urination.
Bladder pressure increases as it fills with urine due to increased fluid volume, leading to activation of the micturition reflex.
Abnormalities in this reflex can lead to conditions such as urinary incontinence or urinary retention.
The pressure exerted by a fluid at equilibrium due to gravity; important for understanding fluids in biological systems like blood and urine.
Autonomic Nervous System: A part of the peripheral nervous system that controls involuntary bodily functions such as heart rate, digestion, and respiratory rate.
Somatic Nervous System: \text{Part of the peripheral nervous system associated with voluntary control of body movements via skeletal muscles.}