Lower Urinary Tract Flashcards
What makes up the lower urinary tract?
bladder and urethra
what is the purpose of the pelvic floor?
muscles which contain urine and abdominal organs
What is the bone seen anterior/ventral to the bladder?
pelvic symphysis
what type of joint is the pelvic symphysis
secondary cartilaginous
what is seen posterially/dorsally in male mammals?
ductus defrens, seminal vessels and vesicular glands
where do ureters enter the bladder?
posterially/dorsally
Where do the urinary and reproductive tracts meet in the male?
prostate gland
through what does urine exit the body in female domestic species?
vestibule formed by the joining of urethra and vagina inside the body
where does urine exit the body in female primates?
separately from the vagina
where does urine exit the body in male domestic species?
through the urethra which is also the exit of the reproductive tract
where does the ductus defrens enter the urethra?
at the prostate gland
what is the name of the smooth muscle which forms the bladder?
detrusor muscle
what does the thickening of the detrusor muscle around the urethra create?
internal urethral sphincter
what type of muscle is the detrusor?
smooth
how is the bladder voided?
contraction of the detrusor muscle
what part of the nervous system is the detrusor muscle under the control of?
ANS
What are rugae?
folds of mucosa which expand when the bladder distends
what are the rugae formed of?
mucosa
what is the bladder, ureters and urethra lined with?
urothelium
what type of epithelium is uroepithelium?
transitional
what happens to the bladder walls as it distends?
walls become smoother and thinner
what is the trigone formed of?
ureteric orifices and internal urethral meatus
what is there less of in the trigone?
rugae
where are most of the distention sensors found in the bladder and why?
trigone as there are fewer rugae and so less distention possible. This provides a braking system for bladder filling.
what is the external urethral sphincter formed of?
skeletal muscle
is the external urethral sphincter under voluntary control?
yes
what nerve is the external urethral spinctor innervated by?
pudendal nerve
what is the function of ureters entering the bladder at an oblique angle?
acts as a sphincter to prevent reflux of urine
what is the function of the levator ani in quadrupeds?
prevents abdominal contents moving backwards and outwards of the body during periods of increased intrabdominal pressure
what is the function of the levator ani muscle in humans?
supports external urethral sphincter and bladder
what are the two parts of the perineum?
pelvic diaphragm and urogenital diaphragm
what does the perineum form in humans?
pelvic floor
what does the perineum form in quadrupeds?
pelvic outlet
in quadrupeds what is the pelvic floor formed from?
pelvic girdle (pelvic symphysis)
What artery supplies the bladder?
internal illiac artery
what vein drains the bladder?
internal illiac vein
what are the 2 parts of the urethra in males?
pelvic urethra and penile urethra
what are the two subsections of the pelvic urethra in males?
prostatic urethra and membranous urethra
where is the prostatic urethra found?
through prostate
what is the name of the muscle which controls the external urethral sphincter?
urethralis muscle
what type of muscle is the external urethral sphincter made of?
skeletal muscle
what does the external urethral sphincter surround?
proximal urethra
what nerve innervates the external urethral sphincter?
pudendal nerve
what is the function of the external urethral sphincter?
contract and retain urine
where is the penile (spongy) urethra found?
through the penis
what does the prostatic urethra receive alongside the ureters?
ejaculatory ducts and prostatic ducts
where does the membranous urethra run through?
external urethral sphincter
where does the penile (spongy) urethra run through?
corpus spongiosum of the penis
where does the penile urethra open?
external urethral meatus on tip of glans
what is the main function of the male urethra?
conveys urine and semen out of the body
what prevents retrograde ejaculation?
thickened bladder neck
what type of muscle is the urethra made up of?
smooth muscle
how long is the male urethra in a human?
20cm
what is the function of the female urethra?
conveys urine out of the body
how long is the female urethra in a human?
4cm
what type of epithelium is found at the end of the urethra?
stratified squamous epithelium to protect from abrasion
why is UTI so common in females?
proximity of anus and short length of urethra
where does the female urethra run in quadrupeds?
caudally on pelvic floor
where does the urethra open in female quadrupeds?
ventrally at the junction of the vagina and the vestibule
what is the width and length of the urethra in quadrupeds?
varies largely between species
what embryological tissue does the bladder and urethra derive from?
endoderm
what is the cloaca the common opening for?
urinary, GI and reproductive systems
what does the cloaca divide into?
urinary sinus and anal canal
what does the urinary sinus form?
bladder and urethra
what is the allantois?
extension of the developing urinary tract through the umbilicus to the placenta
what is the allantois used for?
waste disposal in utero
when does the allantois close in quadrupeds?
at birth
when does the allantois close in humans?
develops into urachus and then closes
What has happened in the urogenital system by week 8 of gestation?
complete separation between gut and urogenital tracts
when does the urachus occlude?
when the bladder is formed
what is patent urachus?
urachus remains open and so urine drains from the umbilicus as well as the urethra
what happens to the urachus in normal development?
closes and forms fibrous tissue
what is urachal diverticuli?
only half of the urachus closes leaving a pouch which leaves the individual with frequent/constant urine infections
how is the bladder innervated?
sensory stretch receptors
parasympathetic
sympathetic
somatic (motor nerves)
where does sensory information come from in the bladder?
stretch receptors
what nerve of the parasympathetic nervous system innervates the bladder?
pelvic splanchnic nerve
what is the effect of the parasympathetic pelvic splanchnic nerve?
motor contraction of the detrusor and relaxes internal sphincter
what is the role of the parasympathetic pelvic splanchnic nerve?
micturition
what nerve of the sympathetic nervous system is involved in continence?
hypogastric nerves
what is the role of the sympathetic hypogastric nerves?
relaxes (inhibits) detrusor and contracts internal sphincter
what are the sympathetic hypogastric nerves in control of?
continence
what somatic nerve innervates the bladder?
pudendal nerve
what effect does the pudendal nerve have have on the bladder?
motor control of external sphincter
what happens when the bladder begins to fill?
stretch receptors in the trigone trigger visceral afferent receptors which travel to the sacral region of the spinal cord in pelvic nerves
where does parasympathetic motor innervation of the bladder come from?
sacral region of the spinal cord in pelvic nerves
what does parasympathetic innervation of the bladder lead to?
contraction of detrusor muscle
inhibits/relaxes internal urethral sphincter
how does continence work by sympathetic innervation?
relaxes detrusor muscle
contracts internal urethral sphincter
how does continence work via voluntary/somatic control?
tone in external urethral sphincter
innervated by pudendal nerve
when does the control of micturation arise in different species?
different times depending on species, some never develop control of micturation
how does the brain become aware of the bladder filling?
afferents synapse with neurons which pass up cords into the brain
what do descending neurones cause when urination is appropriate?
increased parasympathetic signals to the bladder cause detrusor to contract and internal urethral sphincter to relax
inhibited pudendal nerve signals causes the external urethral sphincter to relax
what do descending neurones cause when urination is not appropriate?
inhibition of parasympathetic signals/increase in sympathetic signals to the bladder causing the detrusor to relax and internal urethral sphincter contracts
increased pudendal nerve signaling causing external urethral sphincter to contract
what are the 3 types of incontinence?
overflow
stress
urge
what is overflow continence caused by?
urethral blockage causing the bladder to empty properly
what is stress incontinence caused by?
a relaxed pelvic floor causing release of urine under increased abdominal pressure
what is urge incontinence caused by?
bladder over sensitivity to urination causing near constant need to urinate with little result
