S1: anatomy of the urinary system Flashcards
What is the anatomical position of the kidneys?
The kidneys lie in the retroperitoneum on the posterior abdominal wall on either side of the vertebral column (T11 – L3)
Right kidney is displaced by the liver so its 12mm lower than the left kidney
Describe the normal size of each kidney
11cm long and 6cm wide
What is the normal blood supply of the kidney?
Single renal artery (although not uncommon to have one or more accessory renal arteries)
What other arteries can the kidneys sometimes be supplied by?
Superior mesenteric
Suprarenal
Testicular
Ovarian
What are the two main regions in the kidney?
1) Outer dark brown cortex
2) Inner pale brown medulla
Describe the course of the ureters (similar in both sexes)
1) Arises from pelvis of kidney
2) Descends on top of psoas major muscle to reach pelvic brim
3) Crosses in front of common iliac arteries
4) Runs postero-inferiorly on lateral walls of pelvis
5) Curves antero-medially to enter the bladder
Describe the vesicoureteral junction
Most distal portion of the ureter where is attaches to the bladder
Approaches the bladder at an oblique angle which reduces reflux of the urine
Describe the course of the ureter in males
The ureter passes under the ductus deferens & superior to seminal vesicles
Describe the course of the ureter in females
Ureter descends posterior to the ovary & into the base of the broad ligament, passing under the uterine artery
Describe the anatomical position of the bladder
When empty – lies in the pelvis and rests of the symphysis pubis and floor of the pelvis
When filled – enlarges into the abdominal cavity
(on average bladder can hold up to 750 ml)
Describe the bladder wall composition
The bladder is lined with by smooth muscle, known as the detrusor muscle
Muscular folds called rugae (trigone is smooth) & lined with transitional epithelium (urothelium)
Allows the bladder to contract and push the urine into the urethra
What is the trigone?
Triangular region at base of the bladder
Between the ureteric and urethral openings
What are the different sphincters in the bladder & urethra?
Internal urethral sphincter (smooth muscle)
-detrusor muscle runs circularly to form this
-surrounds the bladder neck
-not under voluntary control & thus contract reflexively
External urethral sphincter (skeletal muscle)
-further along the urethra
-under voluntary control
Describe the anatomical position of the prostate
Gland lying below the bladder in the male & surrounds the proximal part of the urethra (prostatic urethra)
Describe the ultra-structure of the male urethra
Longer than the female (20cm compared to 4cm)
Runs through the neck of the bladder, the prostate gland, the floor of the pelvis, the perineal membrane to the penis & the external urethral orifice at the tip of the glans penis
Three parts:
1) Prostatic urethra
2) Membranous urethra
3) Spongy urethra
