1. The Urinary System

2. Mongolian Gerbils

3. Function Remove nitrogenous wastes
Maintain electrolyte, acid-base, and fluid balance of blood
Homeostatic organ
Acts as blood filter
Release hormones: calcitriol & erythropoietin

4. Kidneys as Filters Diuretic- loose water; coffee, alcohol
Antidiuretic- retain water; ADH
Aldosterone- sodium & water reabsorption, and K+ excretion
GFR= 180 liters (50 gal) of blood/day
liters are reabsorbed back into blood
Excrete a protein free filtrate

5. HOW DO KIDNEYS FILTER BLOOD? (p 583)

6. Maintaining Chemical Homeostasis
The Urinary System

7. The Urinary System

8. General Functioning of the Kidney
blood
filtration
General Functioning of the Kidney
tubular reabsorption and secretion
urine
“refreshed” blood

9. Nitrogenous Wastes
urea
uric acid
ammonia

10. Organs of the Urinary System
kidneys
ureters
Organs of the Urinary System
urinary bladder
urethra

11. Urine Water- 95% Nitrogenous waste: urea uric acid creatinine Ions:
sodium
potassium
sulfate
phosphate
From the original 1800 g NaCl, only 10 g appears in the urine

12. Hormonal Control of Kidney Function

13. Hormonal Control of Kidney Function
high plasma solute concentration
low blood volume
heart receptors
hypothalamus

14. Hormonal Control of Kidney Function
hypothalamus
posterior pituitary
antidiuretic hormone
collecting ducts

15. Hormonal Control of Kidney Function
reduced blood pressure and glomerular filtrate
juxtaglomerular apparatus
renin

16. Hormonal Control of Kidney Function
angiotensinogen
angiotensin I
renin
angiotensin II

17. Urinalysis Why do doctors ask for a urine sample? characteristics:
smell- ammonia-like
pH , ave 6.0
specific gravity– more than 1.0; ~
color- affected by what we eat: salty foods, vitamins

18. Odor odor- normal is ammonia-like
diabetes mellitus- smells fruity or acetone like due to elevated ketone levels
diabetes insupidus- yucky
asparagus---

19. pH- range ave 6.0
vegetarian diet- urine is alkaline
protein rich and wheat diet- urine is acidic

20. Color Color- pigment is urochrome
Yellow color due to metabolic breakdown of hemoglobin (by bile or bile pigments)
Vitamins- vitamin C- bright yellow
Infection- cloudy