Lower Urinary Tract & Ureters Flashcards
What is the function of the ureters?
Passage of urine from kidneys to bladder
- via peristaltic contractions of smooth mm in ureter wall, and filtration pressure of glomeruli
- convey approx 1.2L of urine daily
Describe the anatomy of the ureters
- paired narrow tubes between kidneys and bladder
- 25cm long
- retroperitoneal
- thick muscular tubes
Describe the anatomical course of the ureters
Abdominal section (from kidney to bladder):
- runs along psoas
- crosses over genitofemoral nerve at L1-2 level
Pelvic section:
- at bifurcation of common iliac a (L5-S1)
- ureters leave psoas and pass over SIJ to enter pelvis
- terminal parts pierce posterior lateral angle of bladder
(males: ureters crossed by vas deferens before entering bladder)
at which spinal levels:
- do the ureters cross over the genitofemoral nerve and change from the abdominal to the pelvic section?
- do the ureters leave the psoas and cross the SIJ to enter the pelvis?
L1-2:
- ureters cross genitofemoral nerve
- change from abdominal ureters to pelvic ureters
L5-S1:
- ureters leave psoas and cross over SIJj to enter pelvis
What are the histological layers of the ureters?
Mucosa:
- transitional epithelium (specialized epithelium designed to distend to accomodate fluid; basal layer cells are cuboidal or columnar)
- continuous with mucosa of renal pelvis (superiorly) and bladder (inferiorly)
Muscularis:
- internal longitudinal
- external circular
- additional external longitudinal in lower 1/3
Serosa / adventita:
- anterior surface: serosa (in contact with peritoneum)
- posterior surface: adventitia
What are the features of transitional epithelium, and in which components of the urinary tract are they found?
Located:
- renal pelvis
- ureters
- bladder
Features:
- specialized epithelum
- change to accomodate fluid
- cells f basal layer are cuboidal or columnar
- appearance transitions between stratified coboidal and stratifeid squamous depending on the degree of distension
What is the innervation of the ureters and bladder?
SNS: T10-L2 via renal, coeliac and hypogastric plexi
PNS: pelvic splanchnic nerves (S2-4)
visceral afferents
What is the arterial supply and vascular drainage of the ureters?
Arterial:
- upper: uretric branch of renal artery
- middle: branches from abdominal aorta, gonadal arteries, common iliac artery, and internal iliac artery
- lower: branches from superior and inferior vesical arteries and uterine arteries
Venous drainage:
- veins with same names as supplying arteries
What is the lymphatic drainage of the ureters?
Abdominal section: para-aortic nodes
Pelvis section: common iliac and internal iliac nodes
Describe the structure and anatomy of the bladder
Surfaces:
- 1 x infero posterior (base)
- 1 x superior
- 2 x infero-lateral
Apex:
- points to top of pubic symphysis
- separated from pubic bones by retropubic space
- median umbilical ligament (remnant of urachus)
Base / fundus:
- formed by posterior wall
Body:
- between apex and fundus
Neck:
- junction of base and inferolateral surfaces
- pierced by urethra at internal urethral orifice
Trigone:
- triangular region at base of bladder
- between 2 uretral oifices and internal urethral orifice
- flaps of bladder mucosa act as valves and prevent vesicouretric reflex
What are the uretral orifices?
Openings of the ureters (right and left) into the base of the bladder
- triangular region between the 2 uretral orifices and the internal urethral orifice is the trigone
What are the peritoneal and visceral relationships of the bladder?
Peritoneal:
- the superior surface and 1cm of base are intraperitoneal
- the rest of the bladder is subperitoneal
Fascia:
- bladder covered by vesical fascia
- fascia contains vesical venous plexus
Male:
- prostate gland below bladder
- between posterior surface of bladder and the rectum: seminal vesicles, vas deferens and retro-vesical pouch
Female:
- superior surface sits below uterus
- infero-posterior surface contacts anterior wall of vagina
- uterovesical pouch: shallow empty pouch that separates bladder from uterus
What is the location of the bladder?
Empty: within pelvic cavity
Full:
- domes up to abdominal cavity as far as umbilical level
- in front of rectum (M)
- in front of vagina (F)
Describe the histological layers of the bladder
Mucosa
- transitional epithelium
- continuous with transitional epithelium of ureters (superiorly)
- rugae (folds) in relaxed state
Muscularis:
- smooth mm referred to as detrusor muscle
- 3 layers: inner and outer layers of longitudinal, middle layer of circular
Adventitia:
- outer layer
- variable amounts of peri-vesical fat
What is the detrussor muscle?
The muscularis layer of the bladder
- contractions eject urine
3 layers:
- inner and outer longitudinal layers
- middle circular layer
What is the lymphatic drainage of the bladder?
- superior surface: external iliac nodes
- fundus: internal iliac nodes
What is the arterial and venous supply of the bladder?
Arterial:
- branches of internal iliac artery
- superior vesical artery supplies antero-superior bladder
- inferior vesical (M) or vaginal (F) arteries supply fundus and neck
Venous:
- veins correspond to names of arteries
- drain into internal iliac vein
What is the nervous supply of the bladder?
Visceral plexus (continuous with hypogastric plexus)
SNS: T10-12
PNS: pelvic splanchnic S2-4; motor supply to detrusor muscle and inhibition of internal urethral sphincter
Describe the internal and external urethral sphincters
Internal urethral sphincter (IUS):
- between neck of bladder and urethra
- formed by thickening of detrusor muscle
- under involuntary (ANS) control
- SNS innervation: IUS tonically contracted
- PNS: causes IUS to relax
External urethral sphincter (EUS):
- between urethra and external urethral orifice
- composed of striated mm where the urethra passes through the pelvic floor
- in females levator ani contributes to continece
- under voluntary control
- maintains constant muscle tone (only relaxes during micturition)
- innervated by pudendal nerve (S2-4)
What are the functions of the urethras?
Both:
- urinary functions (passage of urine from bladder to outer environment during micturition)
Male only:
- reproductive function
What are the histological layers of the male and female urethras?
Male:
Mucosa:
- mostly transitional epithelium continuou with epithelium of bladder
- navicular fossa: stratified squamous epithelium (continuous with epithelium of glans penis)
- mucous secreting glands produce a protective mucous layer
Muscularis:
- urethral smooth muscle a continuation of the detrusor muscle of the bladder
Female:
Mucosa:
- non-keratinized stratified squamous epithelium
- mucous glands in wall of urethra (largest glands are the paired paraurethral glands)
Describe the location and anatomical course of the male and female urethras
Male
- 20cm long
- runs from neck of bladder to externaal urethral orifice at tip of penis
- passes through prostate and corpus spongiosum
Female:
- 4cm long
- runs from bladder neck to external urethral orifice (antero-inferior direction)
- mostly embedded within anterior vaginal wall
Where is the female external urethral orifice located?
Posterior to the clitoris and anterior to the vaginal orifice
What are the 3 components of the male urethra?
- preprostatic and prostatic urethra
- 2-4cm
- receives openings of ejaculatory ducts (union of vas deferens and ducts of seminal vesicles) - intermediate membranous urethra
- 1-2cm
- from apex of prostate to bulb of penis
- surounded by external urethral sphincter and perineal membrane - spongy penile urethra
- 15cm
- passes through bulb and corpus spongiosus of penis
- bulbourethral ducts open into dilated proximal region
- mucous secreting glands along length
- navicular fossa: short dilated region proximal to external urethral orifice
- ends at EUO
