L22*-Bladder physiology Flashcards
(26 cards)
What does the renal pelvis do?
Urine flows from each of the renal calcyces into a funnel-shaped dilation of the upper ureter which is called renal pelvis.
In the renal pelvis, how is the peristatic waves initiated ?
due to gravity and from modified atypical smooth muscle cells.
What does the peristaltic waves do?
They slowly propagate down the ureter, helping to encourage the flow of urine down the ureter in to the bladder.
What can obstruct this urine flow ? and how?
-Kidney stones(nephrolithiasis or ureterolithiasis) and also due to the precipitation of barely-soluble constituents of urine.
-pressure builds up behind these structures and cause pain.
What are the treatments to remove obstruction to the urine flow?
-percutaneous nephrostomy or extracorporeal shock wave lithotripsy.
-sending pulses of ultrasound from high energy to break up the stones -shock wave.
How much can the urinary bladder can expand?
-can expand enormously size, from an empty volume<100mL to typical maximum volume of 500-1000mL.
Does the urine volume change when excreting?
Once in the lower urinary tract, urine is extracted essentially unchanged ( apart from some signalling molecules and cells originating from the urothelium) .
And the residual volume increases over time.
What does the urinary bladder wall consists of?
and Explain what each are?
-Urothelium
-Lamina Propria
-Detrusor - Smooth muscle of the bladder to contract to increase the pressure in the bladder and the expulsion of urine.
-Serosa - thin outer layer to protect the bladder from expansion.
-epithelial cells-inner layer, POLES allows expansion.
Describe features of Urothelium and why they are important?
-High resistance tight junction between the cells > greatly reduce permeability through the wall.
- urine facing surface has specialised cells called “umbrella cells”.
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How is resistance created in urine flow?
Top layer of epithelial cells project out and spread over the surface like umbrellas. These link the tight junctions together with high resistance.
-Then there is large surface area facing the bladder, relatively few gaps in the cells give high resistance.
Describe the features of Lamina Propria
-contains blood vessels, lymphatics, nerves & interstitial cells(of Cajal) in a connective tissue mesh.
-sensory nerve terminals in this area> involved in detecting chemical and mechanical stimuli(filling state of bladder).
- interstitial cells > mediate signalling between the urothelium and the detrusor smooth muscle without involving nerves.
Describe the features of Detrusor
-Smooth muscle cells run in bundles, bundles are arranged in an irregular basket-weave pattern.
-muscle bundles are innervated by autonomic nerves.
-parasympathetic nerves represent the dominant innervation and their main neurotransmitter is ACh on M3 muscarinic receptors to cause contraction.
-sympathetic nerves release NAd onto beta3-adrenoreceptors to cause relaxation.
2 types of Ca2+ imaging in smooth muscle of the urinary bladder.
-nerve(field) stimulation
-local agonist (ATP) application.
What are the 2 principles of bladder physiology ?
1.Continence
-low pressure reservoir for storage of waste products
-continually active sphincter to prevent leakage. outflow tract is relaxed.
2.Voding
-relaxation of sphincters
-increase pressure in reservoir , for storage and excretion of the substances.
What are the 4 things 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 components of the pelvic floor anatomy?
-urethra
-vagina
-anal canal
-bladder
-rectum
-levator ani
-puborectalis
Where is the pelvic floor is located ?
Pelvic floor is located underneath the bladder helping to support the base of both reservoirs which can affect the urinal contents.
What are the components of female urogenital tract? And what can you say about External urethral meatus and the distance between bladder and urethra ?
-uterus
-rectum
-bladder neck
-vagina
-Trigone
-Bladder
-Urethra
-External urethral meatus > low resistance bc of shorter length
- bladder and urethra is close to the vagina.
what are the components of the male urogenital tract ?
-Trigone
-Internal sphincter
-Rectum
-Prostate > prostate gland gets bigger as we get older.
-External sphincter
-Membranous urethra(higher resistance bc if longer than urethral tube. ****
-Bladder
- Internal urethral orifice
-Periprostatic urethra.
-Prostatic urethra
-pelvic floor
-penile urethra
-external urethral orifice
-tests
What is urethra surrounded by? and type of control of internal and external ?
-Urethra is surrounded by skeletal muscles, forms the ecternal *****
-Internal - autonomic control
-external layer of bladder - somatic control
What does the cross section of female urethra has?
-Striated muscle
-circular smooth muscle
-longitudinal smooth muscle
-Lamina Propria
-Vagina
Explain the mechanisms of Somatic system, Sympathetic system and Parasympathetic system in both Continence and Voiding?
1.Continence >
-Somatic system active keeps striated sphincter contracted.
-Sympathetic system active constricts smooth muscles sphincter.
-Keeps storage element relaxed parasympathetic system inactive.
- Voiding>
-Somatic system and parasympathetic system switched off.
-Sphincters relax within the bladder.
-Parasympathetic system activated storage element walls contract.
What are the 2 types of reflexes in the bladder?
- Storage reflex
- Voiding reflex
- Sensory nerves from Pontine Micturition centre (PMC) -with pones and process of urination. sits in the brain and receives sensory inputs from the brain. activate the decsing system to seitch the ..system. switch on the parasympathetic nerve to the bladder causing it to contract.****
What are the measure of normal human urodynamics?
In order :-
Urethral pressure
Urethral EMG
Intravesical pressure
Urine flow
