Urinary V Lecture Flashcards
Ureter is specialized to ____
transport urine to bladder
the ureter has 3 layers:
- mucosa : transitional epithelium and lamina porporia
- muscularis: inner longitudinal, and outer circular smooth muscle
- adventitia: outer CT layer holding ureter in place
urine stretches muscularis layer stimulating ….
peristalic waves
peristalic waves:
waves of contraction which propel urine toward bladder
(regardless of gravitational pull)
only operate one way
signaled by urine stretching muscularis (bladder filling)
urinary bladder is specialized for….
urine storage
the urinary bladder has 3 layers:
- mucosa: transitional epithelium. stratified (barrier) lamina propria
- muscularis: detrusor muscle- extensive smooth muscle layers (contract to void urine)
- adventitia or serosa: outer CT layer
transitional epithelium
creates a barrier- has the ability to stretch or flatten depending on the fullness of the bladder
rugae:
when the bladder is empty, the wall is thrown into folds called rugae. these folds dissapear when the bladder is full (stretched)
detrusor muscle:
smooth muscle in wall stretches and thins allowing for stretching w/o increasing internal pressure.
under control of autonomic nervous system.
what is the capacity of the urinary bladder
500-1000 ml
trigone:
triangular region formed by openings of ureters and urethra
(site of persistent infections)
Urethra:
carries urine out of body
differences: urethra: m/f
F: 3-4 cm long
M: 20 cm long, 3 regions
urinary sphincters:
- internal urethral sphincter smooth muscle controlled by ANS
- external urethral sphincter: skeletal muscle, voluntary- controlled by somatic NS
micturition:
the act of emptying the urinary bladder
micturition is a …..
spinal reflex with CNS influence
role of nervous system (2 parts) in micturition
- parasympathetic nervous system: contracts detrusor muscle, relaxes internal urtheral sphincter
- sympathetic nervous system: active during bladder filling, relaxes detrusor and contract internal urethral sphincter to prevent voiding
micturition: involuntary reflex
- urine fills the bladder and stretches its wall
- stretch receptors send a signal via sensory afferent fibers from the sacral portion of the spinal cord
- parasympathetic efferent fibers stimulate detrusor muscle to contract and the internal urethral sphincter to relax causing micturition
micturition: voluntary control from CNS
- interneurons in the spinal cord commincate the “full bladder” signal to the micturition center of the pons
- if micturition is appropriate, the cerebral cortex facilitates this process and allows external sphincter to relax: urine is voided.
Look at slide about CNS determining urine storage or emptying
do it, now.
urinary incontinence:
inability to control urination
when the higher brain (pontine storage center) is controlling micturition it is acting on the spinal efferents how…
- decreasing parasympathetic activity
- increases sympathetic activity
- increases somatic motor nerve activity
pontine storage center
the part of the higher brain that allows or inhibits micturition at appropriate times.
urinary retention:
bladder unable to expel urine.
(general anesthesia, hypertrophy of prostate in. men
urine output:
the result of all the processes that take place in the kidney.
excretion:
the process of eliminating waste
excretion equation
excretion= filtration - reabsorption + secretion
excretion equation is important because:
- tells us how a substance behaves
ex. pain medication: when to dose - measures kidney function
ex. checks for failure
Tubular reabsorption:
PCT
reabsorption of all nutrients, many electrolytes, most sodium (NA+) and water (obligatory water reabsorption)
tubular reabsorption:
Descending limb of nephron loop
reabsorption of solutes (Na+, K+, Cl-)
tubular reabsorption:
DCT and/or collecting duct:
regulated reabsorption/ secretion
1. ADH
2. Aldosterone
3. Atrial natriuretic peptide (ANP)
4. parathyroid hormone
antidierectic hormone in regulation
stimulates aquaporin synthesis increasin water reabsorption
(regulates water reabsorption)