Week 8 - Micrurition Flashcards
Where is the bladder found?
Posterior to pubic symphysis, anterior to anal canal.
What are the two functions of the bladder?
Temporary storage and assist in gin expulsion of urine.
What is the smooth muscle of the bladder called?
Detrusor
Which vessels supply the bladder?
Internal iliac vessels
Artery so delivered by the superior and inferior vesicular branch on internal iliac
Venous is via vesical venous plexus emptying into internal iliac vein or hypogastric vein
How does the sympathetic nervous system communicatis s with the bladder?
Hypogastric nerve t12-l2
What does the hypogastric nerve do to the bladder?
Relaxation of the detrusor muscle - promotes urine retention
How does the parasympathetic nervous system communicate with the bladder?
Via the pelvic nerve s2-4 - increased signals causes contraction of of detrusor muscle stimulating mic turnitin
How does the somatic nervous system supply voluntary control to the bladder?
S2-4 gives rode to the pudendal nerve - inner fates the external urethral sphincter. Relaxes or contracts.
Explain the bladder stretch reflex arc
Bladder fills, walls stretch, sensory nerves detect and transmit to spinal cord. Interneurons in spinal cord relay to parasympathetic efferents - the pelvic nerve. This acts to contract detrusor and stim micturition
Explain what happens if the is a spinal nerve injury above t12?
The afferent signals from the bladder wall are unable to reach the brain and the patient will have no awareness of bladder filling. Also no descending control over the external urethral sphincter and therefore is constantly relaxed.
Also reflex bladder occurs because of spinal reflex of parasympathetic stimulation of bladder filling - bladder empties straight away
What happens if there is a spinal nerve lesion below t12?
Damages the parasympathetic outflow to the bladder - the detrusor muscle will be paralysed, the spinal reflex does not function
Embryologically, where is the bladder derived from?
Hindgut
