1. Getting rid of metabolic wastes!
The Excretory System
Getting rid of metabolic wastes!

2. Excretory System: The Function
To rid the body of wastes due to metabolic activity
This is essential to maintain homeostasis

3. Excretory System: The Organs
SKIN:
Rids body of excess water and salt (SWEAT)
LUNGS:
Rids body of CO2
KIDNEYS:
Filter blood
Maintain blood pH
Maintain blood volume

4. Excretory System: The Kidneys
RENAL:
Refers to anything doing with the kidneys
Kidneys involved w/ these structures:
Ureter:
Tubes that carry urine to bladder from kidneys
Urinary bladder:
Collects urine for excretion
Urethra:
Transports urine out of body from bladder

5. Kidney Structure Renal Artery: Renal Vein: Renal Cortex:
Carries unfiltered (dirty) blood from heart TO kidneys
Renal Vein:
Carries filtered (clean) blood from kidneys TO heart
Renal Cortex:
Outer portion
Renal Medulla:
“Corn” shaped inner portion
Nephrons:
Functional unit of the kidneys!
Lie between cortex and medulla
Millions of them!

6. Excretory System: The Nephron

7. Excretory System: The Nephron
Nephrons are the functional units of the kidney
This is where filtration, pH balance, and blood volume are maintained!
Glomerulus:
Bundle of capillaries
Bowman’s Capsule:
Surround glomerulus
Loop of Henle:
Maintains water balance
Collecting Duct:
Collects wastes from filtered blood
Connected to ureter

8. Excretory System: Nephron Process
Nephrons clean and maintain blood in 3 steps:
Filtration (filtering of blood):
Glomerulus  PRESSURE  Bowman’s Capsule
Blood is filtered of water, urea, salts, and other materials
These filtered materials called FILTRATE
Reabsorption (maintaining blood volume and nutrients)
The “good” part of filtrate is reabsorbed by blood
Most filtered water re-enters blood to maintain volume
Secretion: (maintaining blood pH)
The “bad” part of filtrate is secreted back into filtrate
H+ ions, some water, salts, and urea
These together are called URINE!
Urination:
Urine in Loop of Henle  Collecting Duct  Ureter  Bladder  Urethra