What is the function of the urinary tract
Collect urine produced continuously by the kidneys
To store collected urine safely
To expel urine when socially acceptable
Where are the kidneys located
Retroperitoneal between T11 and L3
What is the blood supply of the kidneys
Renal artery direct from the aorta at L1 level
How much urine does each kidney produce per day
1-1.5L of urine per day
How long are the ureters
25-30cm
Describe the course of the ureters
Run over the poses muscle, cross the iliac vessels at the pelvic brim and insert into the trigone of bladder
What are the three points of narrowing in the ureter
Pelvo-uteric junction
Crossing iliac vessels
Crossing trigone of bladder
How is reflux of urine prevented
Valvular mechanisms at the vesicoureteric junction
Describe the nervous control of the bladder and sphincter
Describe the neural control of micturition
Cortex = voluntary control
Pontine micturition centre/periaqueductal grey = coordination of voiding
Sacral micturition centre
Onuf’s nucleus = guarding reflex
Is the detrusor muscle relaxed or contracted during storage?
Relaxed.
Is the detrusor muscle relaxed or contracted during voiding?
Contracted.
Is the urethral sphincter relaxed or contracted during storage?
Contracted.
Is the urethral sphincter relaxed or contracted during voiding?
Relaxed.
What type of epithelium lines the bladder?
Urothelium (transitional epithelium) - pseudo-stratified.
Describe the physiology of micturition.
The bladder fills and stretch receptors are stimulated. Afferent impulses stimulate parasympathetic action of detrusor muscle; it contracts. The urethral sphincters relax; this is mediated by inhibition of the neurones to them. The PAG is stimulated.
Describe the storage phase
Describe the filling phase
Describe the micturition reflex
Describe the process of bladder emptying
Describe the guarding reflex
Detrusor relaxation is controlled by what nerve
Sympathetic stimulation T11-L2
External urethral sphincter contraction is controlled by what nerve
Pudendal stimulation (S2-S4)
Detrusor contraction is controlled by what nerve
Pelvic nerve -= Parasympathetic stimulation S2-S4