1. The Urinary System
Organs: Kidneys (creates urine), ureters (transport), urinary bladder (stores), urethra (transport)

2. Kidney Function
Filter fluids from bloodstream and maintain homeostasis in body
Rids body of wastes, excess ions, toxins, and drugs in urine
Regulate blood volume, pH, salt content
Secretes renin – regulates blood pressure
Secretes erythropoietin – increases rbc production

3. Kidney Anatomy 5” long, 2.5” wide Renal capsule: Renal cortex:
encloses kidney
Renal cortex:
outer region
Renal medulla:
deep to cortex w/ medullary pyramids separated by renal columns
Renal hilus:
medial indentation
Rich Blood Supply
Renal artery  segmental arteries  lobar arteries  interlobar artery  afferent arteriole  glomerulus capillaries  efferent arteriole  peritubular capillaries  interlobular vein  arcuate vein  interlobar vein  renal vein

4. Nephrons Nephrons form urine Glomerulus: knot of capillaries
Renal tubule w/ enlarged bowman’s capsule at end
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting ducts: receive urine from many nephrons; deliver urine to renal pelvis

5. Urine Formation Filtration Tubular reabsorption Tubular Secretion
Water and solutes smaller than proteins are forced thru capillary walls and pores of glomerular capsule into the renal tubule
Tubular reabsorption
Water, glucose, amino acids, and needed ions are transported out of the filtrate into the tubule cells and then enter the capillary blood
Tubular Secretion
Urea, H+, K+, creatinine, and drugs are removed from the peritubular blood and secreted by the tubule cells into the filtrate
Urine: 1-2 L produced every 24 hrs

6. Ureters 10-12” long tubes Carry urine from kidneys to bladder
Peristalsis propels urine transport
Valve-like folds prevent back flow from bladder

7. Urinary Bladder Smooth, collapsible muscular sac
Temporarily stores urine
Empty: 2-3” long
Full: 5”long and stores 1-2 pints urine

8. Urethra Thin walled tube
Carries urine (by peristalsis) from bladder to outside the body
Females: 3-4” long, opening is anterior to vaginal opening
Males: 8” long, opening at tip of penis
Double function: passageway for sperm ejaculation
internal urethral sphincter:
Involuntary smooth muscle, keeps closed when urine is not being passed
External urethral sphincter:
Voluntary skeletal muscle through pelvic floor
Micturition – emptying the bladder
200mL urine collects and activates stretch receptors and cause bladder to contract to force open internal urtheral sphincter…feel urge to void

9. Fluid and Electrolyte Balance
2/3 water in intracellular fluid (ICF)
1/3 water in extracellular fluid (ECF)
Electrolytes: charged ions that conduct electrical current, alters blood volume and blood pressure
Ex. sodium, potassium, calcium ions
Electrolyte balance maintained by hormones
Antidiuretic hormone (ADH)
Aldosterone

10. Acid-Base Balance Proper function, blood pH between 7.35-7.45
Alkalosis rise in blood pH above 7.45
Acidosis drop in pH below 7.35
Blood Buffers
Respiratory System
Renal Mechanisms
Excreting bicarbonate ions
Reabsorbing or generating new bicarbonate ions