Urinary System

Front 1

Kidney

Back 1

1) located in depression (gutter) lateral to bodies of vertebral column, between last rib and iliac crest; superior end of kidney overlaps 12th rib
2) retroperitoneal structure; surrounded by fat and fascia
3) supplied by renal artery (from abdominal aorta) and drained by renal vein (to inferior vena cava)
a) very large blood supply
b) kidney function - filters blood to remove waste products for excretion in urine; maintains proper water and salt balance of blood
c) receives 25% of blood flow from each heart beat

Front 2

Structure of Kidney

Back 2

a) hilus - medial indentation; entry-exit point for renal artry & vein and ureter
b) renal cortex - outer layer of kidney; location of glomerulus (sites of blood filtration)
1) renal columns - region of cortex that projects down between renal pyramids
c) renal medulla - inner layer of kidney
1) renal pyramids - medullary tissue in shape of pyramids, with apex pointing toward hilus; urine drains from apex of pyramid into minor calx
d) minor & major calyx - receives urine from renal pyramid apex and drain intoi renal pelvis
e) renal pelvis - expanded portion of ureter within hilus

1) ureter:
a) exits hilus on medial side of kidney
b) runs inferiorly (retroperitoneal), passing over common iliac arteries, to enter posterior side of bladder

Front 3

Suprarenal (adrenal) Glands

Back 3

1) endocrine glands located at superior pole of kidneys
a) secrete hormones directly into bloodstream
2) consists of two parts:
a) adrenal cortex - outer layer
1) secretes adrenocortical (steroid) hormones
b) adrenal medulla - inner layer
1) modified postganglionic sympathetic collateral ganglion
2) innervated by preganglionic sympathetic fibers from greateer splanchnic nerve - activation of sympathetic nervous system stimulates hormone secretion by adrenal medulla cells
3) major secretory product is epinephrine (adrenaline)

Front 4

Bladder

Back 4

1) distensible muscular sphere located behind pubic symphysis
a) retroperitoneal organ - only superior & posterior walls covered by peritoneum
b) rectovesical pouch (recess) - depression of peritoneum in male between rectum & bladder; lowest point of male peritoneal cavity
2) bladder is surrounded by loose connective tissue
a) base of bladder (nondistensible region) anchored in position to prostate gland
b) rest of bladder can distend upward, pushing between anterior body wall and peritoneum as it fills with urine - can expand up to level of umbilicus
3) nondistensible base of bladde consists of triangular region defined by entrances of two ureters and exit of urethra
4) contraction of bladder stimulated by parasympathetic nervous system
a) preganglionic parasympathetic nerves from S2-S4 spinal cord levels
b) postganglionic parasympathetic neurons located in terminal ganglia within bladder wall

Front 5

Urethra

Back 5

1) carries urinefrom bladder to exterior
a) in males, prostate gland located between bladder & sphincter urethrae muscle
1) urethra passes through (surrounded by) prostate gland
2) enlargement of prostate may consist of opening & make micturition (urination) difficult
2) passage of urine to outside controlled by sphincter urethrae muscle - surrounds urethra
3) urethra is short in female - more prone to bladder infections than males
4) urethra long in males - parts of male urethra
a) prostatic urethra - passes through prostate gland
b) membranous urethra - passes through sphincter urethrae muscle
c) spongy (penile) urethra - passes through corpus spongiosum (erectile tissue) of penis