Ureter, Urinary Bladder, Urethra Flashcards
Where is the ureter located?
Retroperitoneal from renal pelvis down to bladder and attached to the posterior abdominal wall
Anatomical Course of Ureter
Descends along anterior surface of ____
First step
Descends along anterior surface of psoas major
L2-L5
Anatomical Course of Ureter
Crosses the ____ at level of ____ to enter pelvic cavity
Second step
Crosses the pelvic brim at level of sacroiliac joints to enter pelvic cavity
Anatomical Course of Ureter
Descend along ____
Third step
Descend along lateral pelvic walls
Anatomical Course of Ureter
Turn anteromedially at the level of ____ to travel transversely towards bladder
Fourth step
Turn anteromedially at the level of ischial spines to travel transversely towards bladder
Anatomical Course of Ureter
Pierces lateral aspect of bladder walls in ____ manner
Fifth step
Pierces lateral aspect of bladder walls in oblique manner
Creates a one-way valve preventing backflow of urine
Name the 3 constrictions of the ureter
- Ureteropelvic junction
- Pelvic inlet (where ureters cross the iliac vessels)
- Vesico-ureteric junction (narrowest - entrance to bladder)
Clinical significance of constrictions
Common sites of obstruction by calculi
Ureteral Pain
What does ureteral pain result from?
Strong peristaltic waves of contraction pass down ureter in attempt to pass stone onward -> Smooth muscle spasms causes colicky pain
Ureteral Pain
How does ureteral pain come about? (spinal cord)
Afferent nerve fibers of renal pelvis and ureter enter spinal cord at segments T11, T12, L1 and L2 -> Pain referred to corresponding dermatomal distribution along flank, loin and groin
Ureteral Pain
Ureter lies in close proximity to the ____ nerve and pain is referred along ____ branch of the nerve -> Pain over tip of penis (male) and labia major (female)
Ureter lies in close proximity to the genitofemoral nerve and pain is referred to genital branch of the nerve -> Pain over tip of penis (male) and labia major (female)
Ureteral Pain
Ureter lies in close proximity to the ____ nerve and pain is referred along ____ branch of the nerve -> Pain over front of thighs
Ureter lies in close proximity to thegenitofemoral nerve and pain is referred along femoral branch of the nerve -> Pain over front of thighs
Urinary bladder is a ____ and ____ organ
Urinary bladder is a hollow and distensible organ
Where is the urinary bladder located?
On floor of pelvic cavity, inferior to peritoneum and posterior to pubic bones
Urinary bladder expands ____ into abdomen when full
Urinary bladder expands superiorly into abdomen when full
Male Urinary Bladder
Upper part of posterior surface is covered by ____
Upper part of posterior surface is covered by peritoneum
Male Urinary Bladder
Lower part of posterior surface separated from the ____ by ____ , seminal vesciles and the rectovesical fascia
Lower part of posterior surface separated from the rectum by vasa deferens, seminal vesicles and the rectovesical fascia
Male Urinary Bladder
Neck of bladder rests upper surface of ____
Neck of bladder rests upper surface of prostate
Female Urinary Bladder
Posterior surface separated from ____ by ____
Posterior surface separated from rectum by vagina
Female Urinary Bladder
Superior surface related to ____
Superior surface related to uterovesical pouch
Female Urinary Bladder
Neck of bladder rests directly on upper surface of ____
Neck of bladder rests directly on upper surface of urogenital diaphragm
no prostate
Internal features of bladder
What is the muscle in the urinary bladder?
Detrusor (smooth muscles)
Function of detrusor muscle
Contracting in response to signals from nervous system and empty bladder when necessary
What is the neck of the bladder formed by?
Convergence of the fundus and 2 inferolateral surfaces
Internal features of bladder
When bladder is empty, the walls of it have a series of ridges, thick mucosal folds known as ____ that allow for ____ of bladder
When bladder is empty, the walls of it have a series of ridges, thick mucosal folds known as rugae that allow for expansion of bladder
Only seen when bladder is empty
Internal features of bladder
What is the trigone of the bladder?
Smooth triangular region on base of internal urinary bladder and is seen in between 2 ureteric orifices/openings and internal urethral orifice
No rugae even when urinary bladder is empty (always smooth)
What are the layers of the bladder wall?
- Mucosal - transitional epithelium
- Lamina propria
- Submucosa
- Detrusor muscle
- Peritoneum
Function of submucosa of urinary bladder
Provides support and elasticity to the bladder
What are the 2 key functions of the urinary bladder?
- Temporary storage of urine
- Assist in expulsion of urine
What is the maximum capacity of the urinary bladder?
About 500ml
What can cause urinary retention?
Obstruction distal to bladder neck
- Benign Prostatic Hyperplasia
- Bladder stone (cystolithiasis)
- Large blood clot (haematuria)
- Urethral structures
Where are the 2 sphincters located and what are their names?
Urethra
Internal and External urethral sphincter
Sphincters are ____ muscles that open and close passages in the body to regulate flow of substances such as ____ through the body
Sphincters are circular muscles that open and close passages in the body to regulate flow of substances such as bile, urine and feces through the body
What forms the internal urethral sphincter?
Circular muscle fibres at base of bladder becomes thickened
Where is the internal urethral sphincter located?
Bladder neck
Internal urethral sphincters are ____ muscle fibers under ____ control
Internal urethral sphincters are smooth muscle fibers under autonomic control
Function of internal urethral sphincters in males and females
Maintains urinary continence - controls release of urine into urethra
Function of internal urethral sphincters in males
Prevents seminal regurgitation during ejaculation
External urethral sphincters are ____ muscle under ____ control
External urethral sphincters are skeletal muscle under voluntary/somatic control
Which nerve is the external urethral sphincter innervated by?
Pudendal nerve (S2-4)
Provides voluntary control over micturition
What are the blood supplies of the bladder?
- Superior vesical
- Inferior vesical
- Obturator
- Uterine arteries (female)
Lymph of urinary bladder mostly drains into ____ nodes and a few from superolateral surface drains into ____ nodes
Lymph of urinary bladder mostly drains into internal iliac nodes and a few from superolateral surface drains into external iliac nodes
Veins of bladder do not follow arteries but form a plexus that converges on ____ plexus in groove between ____ and ____ which drains backwards across the pelvic floor into the ____ veins
Veins of bladder do not follow arteries but form a plexus that converges on vesico-prostatic plexus in groove between bladder and prostate which drains backwards across the pelvic floor into the internal iliac veins
Which nervous system regulates function of bladder?
Autonomic nervous system
Sensory pathway of bladder
Afferent nerve fibers from bladder wall to CNS and signals to the brain the need to urinate when bladder becomes full
bladder contains stretch receptors to detect bladder filling
What is the sympathetic nerve that innervates the bladder?
Hypogastric nerve (L1-L2)
Function of sympathetic innervation of bladder
- Inhibits contraction of detrusor muscle
- Contracts internal urethral sphincters which closes
-> Urinary retention
What is the parasympathetic nerve that innervates the bladder?
Pelvic splanchnic nerve (S2-4)
Function of parasympathetic innervation of bladder
- Stimulate contraction of detrusor muscles
- Inhibit action of internal urethral sphincter
-> Micturition
What is the somatic nerve that innervates the bladder?
Pudendal nerve (S2-4)
Function of somatic innervation of bladder
Controls external urethral sphincter -> voluntary control over micturition
Micturition reflex in infants
When bladder reaches its micturition threshold, stretch receptors on bladder wall send signals to ____ via the ____ nerves. Interneurons within spinal cord relays signals to ____ which causes ____ of detrusor muscle and ____ of internal urethral sphincter and ____ of urination -> ____ spinal reflex
When bladder reaches its micturition threshold, stretch receptors on bladder wall send signals to S2, S3 and S4 via the pelvic splanchnic nerves. Interneurons within spinal cord relays signals to parasympathetic efferent fibres which causes contraction of detrusor muscle and relaxation of internal urethral sphincter and initiation of urination -> primitive spinal reflex
Micturition reflex in adults
Facilitated and inhibtied by ____ and subject to ____
Facilitated and inhibtied by higher brain centers and subject to voluntary facilitation and inhibition
Micturition reflex in adults
What is the simple stretch reflex inhibited by in adults?
Activity of cerebral cortex until the time and place for micturition are favourable
Micturition reflex in adults
What happens when it is not convenient to urinate?
CNS sends back an inhibitory signal to keep sphincters closed and prevent voiding
Micturition reflex in adults
Inhibitory fibres pass downwards with ____ to ____ of spinal cord to innervate ____ nerve
Inhibitory fibres pass downwards with corticospinal tracts to S2-4 of spinal cord to innervate pudendal nerve
Micturition reflex in adults
Spinal cord through ____ nerves signals detrusor muscle of bladder to ____ and internal urethral sphincter to ____ . Voluntary ____ of external urethral sphincter closes urethra and micturition follows.
Spinal cord through pelvic splanchnic nerves signals detrusor muscle of bladder to contract and internal urethral sphincter to relax . Voluntary relaxation of external urethral sphincter closes urethra and micturition follows.
Function of urethra
Vessel responsible for transporting urine from bladder to external opening in the perineum
Difference of urethra between males and females
- Female: Short (3-4cm)
- Males: Long (15-20cm)
Why are females more susceptible to UTI?
- Shorter urethra -> easier for pathogens to enter and infect urinary tract
- Urethral proximity to anus -> bacteria from large intestine often cause UTI -> proximity allows bacteria to easily access urethra
What are the 3 types of bladder dysfunction due to spinal cord injury?
- Atonic bladder
- Automatic bladder
- Autonomous bladder
When does atonic bladder occur?
Spinal shock
- Immediately after spinal injury and may last for a few days to several weeks
Atonic bladder:
Bladder becomes greatly ____ and overflows.
Bladder wall muscle is ____, internal sphincter muscle tightly ____ and external sphincter muscle ____
Atonic bladder:
Bladder becomes greatly distended and overflows.
Bladder wall muscle is relaxed, internal sphincter muscle tightly contracted and external sphincter muscle relaxed
Which spinal cord lesion does automatic reflex bladder occur at?
Cord lesion above level of parasympathetic outflow (S2-4)
- Injury above T12
If injury above T12: disrupts brain’s ability to control bladder but ____ remains intact
If injury above T12: disrupts brain’s ability to control bladder but reflex arc remains intact
Automatic Bladder:
Bladder fills and empties ____
Afferent signals unable to reach brain and patient has no awareness of bladder filling -> Loss of descending control over ____ and no ____ control over urination
Automatic Bladder:
Bladder fills and empties automatically
Afferent signals unable to reach brain and patient has no awareness of bladder filling -> Loss of descending control over exernal urethral sphincter and no voluntary control over urination
Which spinal cord lesion does autonomous reflex bladder occur at?
Sacral segments
- Injury below T12
If injury below T12: damaged ____ outflow to bladder and ____ does not function
If injury below T12: damaged parasympathetic outflow to bladder and spinal reflex does not function
detrusor muscle paralysed and cannot contract
Autonomous bladder:
Bladder fills to capacity and ____
Continual ____ occurs once bladder is full and bladder may be partially emptied by manual compression of lower part of anterior abdominal wall
=> recurrent ____ and back-pressure effects on ____ and ____
Autonomous bladder:
Bladder fills to capacity and overflows
Continual dribbling occurs once bladder is full and bladder may be partially emptied by manual compression of lower part of anterior abdominal wall
=> recurrent UTI and back-pressure effects on ureters and kidneys
