Micturition Flashcards
What are the ureter walls made of?
Smooth muscle
What is incontinence?
The complaint of any involuntary loss of urine
What innervation does the detrusor muscle of the bladder receive?
Parasympathetic - stimulated during micturition, inhibited during filling
What innervation does the internal urethral sphincter receive?
Sympathetic - stimulated during filling, inhibited during micturition
What innervation does the external urethral sphincter receive?
Somatic motor - stimulated during filling, inhibited during micturition.
VOLUNTARY skeletal muscle - can prevent urination even if detrusor muscle is contracting strongly
Which reflex is not functional after toilet training as a child?
Bladder stretch reflex
Briefly describe the bladder stretch reflex.
- Bladder fills with urine, bladder walls stretch
- Sensory nerves detect the stretch and transmit a signal to the spinal cord
- Interneurones relay the signal to the pelvic nerve
- Pelvic nerve contracts the detrusor muscle to stimulate micturition
After childhood, when can the bladder stretch reflex regain function again?
Spinal injuries or neurodegenerative disease where the descending somatic pathway is damaged. Usually characterised by a sudden onset of symptoms.
What are the types of incontinence?
- Stress - loss of urine with exertion, sneezing, coughing
- Urgency
- Mixed
Which nerve causes contraction of the detrusor muscle?
Pelvic nerve S2-S4
Which nerve causes constriction of the internal urethral sphincter?
Hypogastric nerve T12-L2
Which nerve causes constriction of the external urethral sphincter?
Pudendal nerve S2-S4
Give 3 functions of the bladder.
- Collects urine
- Stores urine under low pressure
- Stores urine until it is socially acceptable to release urine
