1. Unit 3 Notes: The Urinary/Excretory System

2. (1) Main Organs
Kidneys
Ureters
Bladder
Urethra

4. (2) Functions Filter blood Remove impurities, toxins, excess nutrients
Reabsorb needed water + nutrients

5. (3) Ureter, Bladder & Urethra Function
Ureters: Tubes which carry filtered “liquid waste” towards the bladder.
Bladder: Storage tank for filtered “liquid waste”.
Urethra: Tube which allows filtered “liquid waste” to exit body.

8. (4) Nephrons The nephrons are the filtering units inside the kidneys.
2 Main Structures:
Glomerulus  Bundle of capillaries w/ blood to be filtered.
Renal Tubule  Tubes following capillaries, which collect filtered contents
Bowman’s CapsulePortion of tubule where initial filtration and absorption occurs

11. (5) Urine Formation Steps
1- Filtration:
Water + Small Solutes are forced through capillary walls into Bowman’s Capsule.
2- Reabsorption:
Water, Glucose, Amino Acids & Ions that were filtered out are actively transported back into capillaries and blood.
3- Secretion:
H ions, K ions, urea, and drugs/toxins are forced through capillary walls into renal tubule.

14. (6) Regulating Drops in Blood Pressure
Antidiuretic Hormone (ADH) from Pituitary:
Increases water reabsorption from renal tubule.
Aldosterone from Kidney:
Increases water retention in blood by reabsorbing more sodium from renal tubule.
Angiotensin II from Blood:
Causes vasoconstriction, increasing blood pressure.

15. (7) Don’t Pee It Out… Glucose  Chill out on sweets OR Diabetic?!
Protein  Increased Physical Activity & Pregnancy OR Hypertension & Nephron Disease?!
Pus  Urinary Tract Infection
Blood  Kidney Stones, Infection, Trauma, Anemia ?!
Bile  Liver Disease?!

16. (8) Kidney Dialysis Used in hospitals when kidneys fail (stop working)
Blood is filtered through mechanical pump + tubing which regulates contents
Causes for Kidney Failure:
Repeated kidney infections
Physical Trauma
Heavy Metal / Chemical poisoning
Low Blood delivery (arteriosclerosis)