Urinary System

Excretion

Water Balance

Electrolyte balance

Conservation of importan nutrients

• Control of blood cell formation
• - Erythropoietin

• Regulation of blood pressure
• - Renin

Located at back of abdominal cavity (RETROPERITONEAL)

Between T12- L3

RIGHT KIDNEY lower than left kidney (Due to liver)

Fat and ribs help protect kidneys

Renal fascia & fat anchors kidneys to back wall ((Perpendicular to aorta & ureter))

Nephron

Cortex

Medulla

OUter layer of kidney

• - Renal Comumns in STRIPS
• - Has RENAL CORPUSCLES

Inner layer of kidney

- Contain PYRAMiDS (6-18 per kidney)

-Filled with tubules

• Minor calyx then to
• Major calyx

Renal pelvis

• Kidneys
• Pelvis
• Ureters
• Urinary Bladder

Urethra

~12 inches long

Descends to urinary bladder ((POSTERIOR))

Moves urine by peristalsis

Transitional Epithilium

• Enters slit like opnening
• - Membrane covered
• - Contraction closes opening to prevent backflow into ureter.

Casts solidify to form stones

Ex. Salts and minerals

Triangular region between 3 openings

-Primary site for UTI's

Directly behind pubic bone

3 smooth muscles= DETRUSOR MUSCLE

• Collapsible bag
• -Usually holds 2 cups , up to 4

Trigone= Triangular region between 3 openings

Internal urethral sphncter

External urethral sphincter

Smoot muscle under INVOLUNTARY control

Skeletal muscle under VOLUNTARY control

Urogenital diahragm

~7-8 inches

3 regions

~1-1/2 Inches

Most likely to get Cystitis (UTI)

1/2 full -> stretch receptors acrivated

Sensory neurons stimualated

REflex Arc to spinal cord TELLS ->

Detrusor contracts & INTERNAL urethral sphincter relaxes

Urge to void

EXTERNAL urethral sphincter will either contract or relax

RENAL ARTERY- Supplies oxygentaed blood to kidney

It loops throgh the kidney until it reached a capillary "BOW" called the GLOMERULS.

Filtration site for blood

Composed of almost 50 loops of FENESTRATED capillaries.

Fltrate noves into tubule system called the nephron.

Functional unit of kidney

~ 1 million per kidney

• Three functions w blood:
• -Filtrate
• - Re-absorption
• - Secretion

Two types:

• -Cortical Nephron 85%
• - Juxtamedullary nephron 15%

site for filtration

Located in cortex

~45 gallons of fluid passes DAILY

NO BLOOD CELLS PASS

for making urine

Site for REABSORPTION and SECRETION into blood.

Distal convoluted tubule folds back renal corpuscle

DCT and Arterioles leading to glomerulus

• Proximal convoluted tube
• Loop of henley
• Distal convoluted tubule
• Collecting Tubule
• Collecting Duct

Secretes RENIN tp elevate blood pressure

Secretes ERYTHROPOIETIN to stimulate RBC formation.