Unit 4 Notes: The Urinary System

(1) Main Organs Kidneys Ureters Bladder Urethra

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

(3) Kidney Functions Excretion of nitrogenous wastes Maintain water concentration of blood Maintain electrolyte concentration of blood Regulate blood pH (H ion levels)

(4) 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.

(5) Kidneys & Blood Supply Kidneys use 20% of body’s blood Renal Artery = Entering oxygenated blood Renal Vein = Exiting deox. Blood All blood is filtered through nephrons.

(6) Nephrons 2 Main Structures: Glomerulus  Bundle of capillaries w/ blood to be filtered. Renal Tubule  Tubes following capillaries, which collect filtered contents Bowman’s Capsule = Portion of tubule where initial filtration and absorption occurs

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

(8) Anatomy of Urine Formation Filtration  Bowman’s Capsule of Renal Tubule Reabsorption  Proximal Tube, Loop of Henle & Distal Tubule of Renal Tubule Secretion  Distal Tubule of Renal Tubule

(9) Nitrogenous Wastes Urea: Byproduct of protein metabolism in the liver. Uric Acid: Byproduct of nucleic acid metabolism. Creatinine: Byproduct of creatine metabolism in muscle tissue.

(10) 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

(11) 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?!

(12) 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)