Urinary Continence and Micturition Flashcards
What is the renal pelvis?
Funnel shaped dilation of the upper ureter
Where does urine flow from to the renal pelvis?
From the renal calyces
What encourages movement of urine down the ureter to the bladder?
Peristaltic waves in atypical smooth muscle cells
What may obstruct the ureter?
Kidney stones
What is the treatment for kidney stones?
Percutaneous nephrostomy
Extracorporeal shock wave lithotripsy
Can the bladder expand?
Yes
What does the wall of the bladder consist of ?
Urothelium
Lamina propria
Detrusor smooth muscle
Serosa
What is the urothelium?
High-resistane tight junctions between cells make this impermeable
Urine facing surface has umbrella cells
Signalling to underlying cells
What is the lamina propria?
Contains blood vessels, lymphatics, nerves and interstitial cells of Cajal
Many sensory nerves for the mechanical and chemical stimuli
What is the detrusor?
Smooth muscle cells run in bundles Basket weave pattern Innervated by autonomic neres Parasympathetic dominant ACh on muscarinic 3 receptors Sympathetics release NAd, beta 3 receptors to relax the bladder
What is continence?
Low pressure reservoir for storage of waste products
Continually active sphincter to prevent leakage
What is voiding?
Relaxation of sphincters
Increase pressure in reservoirs
What four things do you need for continence and voiding?
Sensory mechanisms to inform about filling
Higher control centres for voluntary voiding
Reflex pathways to generate voiding
The right muscles to do it
What are the layers to the urethra?
Striated muscle
Circular muscle
Longitudinal muscle
Lamina propria
Describe the neuronal controls of continence
Somatic system is active - keeps striated sphincter contracted
Sympathetic system is active - constricts smooth muscle sphincters
Parasympathetic system is inactive
