Renal anatomy

Question 1

Suprarenal (adrenal) glands

Answer 1

Retroperitoneal on upper pole of each kidney
Each has a cortex with 3 layers and a central medulla - 3 layers of cortex are derived from mesoderm and secrete CCSs and androgens in response to stress - in turn these cause Na and H20 retention to raise blood volume and pressure
Each gland receives 3 arteries but drains by 1 big vein so that a flood of hormone will enter circulation
The left gland drains to left renal vein but on right there is a short wide vein to IVC - may be damaged during surgery causing severe haemorrhage
Medulla derived from neural crest cells and is not unlike symp ganglion secreting catecholamines in response to stress

Question 2

What layers are the kidneys encaspulated and protected by?

Answer 2

Deep to superficial:

• Firm (perirenal/perinrephric)
• Then renal fascia, derived from extra-peritoneal fascia (and including suprarenal gland)
• Then pararenal/paranephric fat

Question 3

What does a nephron consist of?

Answer 3

• Renal corpuscle (glomerulus)
• PCT
• Loop of Henle
• DCT
• Collecting duct

Question 4

Where do ureters lie?

Answer 4

Anterior to psoas major and anterior to branches of lumbar plexus and to the bifurcation of common iliac artery
They are muscular tubes that transport urine to bladder

retroperitoneal on post abdom wall - stones may stick

Enter pelvis from post abdom wall but must reach bladder which is anterior - therefore they pass important medially situated structures as well as BVs and nerves on lateral pelvic wall

M - between vas deferens and seminal vesicle
F - post to ovary, inf to uterine artery

Question 5

Bladder

Answer 5

Urinary reservoir
Muscular sac resting on pelvic floor (by puberty), anteriorly behind the pubic bones in the midline
Fills by its detrusor muscle relaxing, empties by its contraction
Detrusor is under control of parasymp nerves derived from S2,3,4

Bladder lies inferior to peritoneum - as it distends it pushes upwards above and behind it so that the bladder then lies directly behind the ant abdom wall - suprapubic catheter

Question 6

Bladder shape

Answer 6

At upper aspect of pubic symphysis

The ureters reach base of bladder on the pelvic floor and pass obliquely through the bladder wall to prevent reflux

Question 7

Ureters passing through the bladder wall

Answer 7

Ureters pass through the bladder wall obliquely, creating a flap valve that prevents urine that is in bladder from backing up and returning into ureter

Ureters pass obliquely through bladder to prevent reflux

Question 8

Bladder neck

Answer 8

Urethral opening
Male - has a pre-prostatic smooth muscle internal sphincter (symp) to prevent semen back-flowing into bladder

Female - bladder neck is above pelvic floor so that pressure of adjacent pelvic organs contribute to urinary continence

Question 9

Urethra - female

Answer 9

Urinary conduit, bladder to exterior
In female it passes through the external sphincter of striated muscle just inferior to bladder neck, embedded within the ant vaginal wall. Opens in vestibule as an antero-posterior slit immediately anterior to vagina

Question 10

Urethra - male (4 parts)

Answer 10

1. Preprostatic at bladder neck (position of smooth internal sphincter)
2. Prostatic
3. Membranous, surrounded by striated external sphincter
4. Spongy or penile urethra

Question 11

Abdominal aorta

Answer 11

Begins at aortic hiatus of diaphragm at T12
Extends to L4 (inf to umbilicus) where it bifurcates into common iliac arteries (slightly left of midline)
Retroperitoneal - lies on vertebral column

Ant - pancreas, splenic vein, left renal vein, duodenum, root of mesentery plus coils of small bowel, lumbar veins

On the right - cisterna chyli, thoracic duct, azygos vein, IVC

Question 12

Branches of aorta

Answer 12

Three unpaired anterior branches

• Coeliac trunk T12
• SMA (L1) and IMA (L3)

Three paired branches to viscera

• Middle suprarenal arteries
• Renal artieries (L1)
• testicular or ovarian arteries (L2)

Three posterior branches supplying diaphragm/body wall

• Inf phrenic arteries (also supply suprarenal)
• Lumbar arteries
• Median sacral artery

Question 13

IVC tributaries

Answer 13

Three ant visceral tributaries - hepatic veins

Three lateral visceral tributaries - right suprarenal vein (left vein drains into left renal vein), both renal veins, and the right gonadal vein (the left vein drains into left renal vein)

Five lateral abdominal wall tributaries - the inf phrenic vein and four lumbar veins