1. Do Now!!  What is the function of your kidneys?
Why do we excrete urine?
Starting with the kidneys, describe the pathway of urine.

2. Kidney dissection!
Urine for a real treat!!

3. Objectives To identify the organs of the urinary system
To explain the major functions of the urinary system
To explain the structure of the kidney and filtration system
To identify the structures of the kidney in a dissection

4. Some background info The Excretory System Functions:
Removes certain salts and nitrogenous wastes from blood
Maintains water and electrolyte concentrations
Regulates pH and volume of body fluids
Helps control RBC production and blood pressure

5. Major organs and functions
Kidneys: removes substances from blood, forms urine, regulates metabolic processes
Ureters: transport urine from kidneys to the bladder
Urinary bladder: temporarily stores urine
Tubular Urethra: excretes urine to the outside of the body

6. The kidney Refers to Kidney!
Located in retroperitoneum – behind parietal peritoneum, against deep muscles of back
Structures:
Renal Capsule
Renal arteries and veins
Renal Pelvis
Major/Minor calyces
Renal medulla (composed of renal pyramids)
Renal cortex
Nephrons (functional units)
Ureter
Refers to Kidney!

8. Urine composition Approximately 95% water
Urea: by-product of amino acid catabolism (how we can determine amt. of protein in diet!)
Uric Acid: Product of metabolism of certain organic bases
Electrolytes: release ions in water
Factoid!! You produce between liters of urine per day!

9. micturition AKA: Urination!
Distension of bladder triggers stretch receptors, generating sensory impulse to brain, which triggers motor impulse to detrusor muscle, which contracts the bladder! (capacity is about mL)
Release is controlled by external urethral sphincter

10. Let’s label!