1. The Urinary System

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

3. 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. Maintaining Chemical Homeostasis
The Urinary System

6. The Urinary System

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

8. Nitrogenous Wastes
urea
uric acid
ammonia

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

10. Kidney Anatomy renal pyramids renal pelvis renal cortex renal capsule
renal medulla
renal capsule
ureter

11. nephron
renal artery
renal vein
Kidney Anatomy

12. Nephron Functioning blood filtration
tubular reabsorption and secretion
urine
“refreshed” blood

13. efferent arteriole
glomerulus
Bowman’s capsule
afferent arteriole
proximal convoluted tubule
artery
distal convoluted tubule
peritubular capillaries
loop of Henle
vein
collecting duct

14. renal cortex renal medulla
Each kidney contains over 1 million nephrons and thousands of collecting ducts
Glomerulus
DCT
renal cortex
renal medulla
PCT
Collecting duct
Loop of Henle

15. Glomerular Filtration
efferent arteriole
afferent arteriole
Glomerular Filtration
Bowman’s capsule
glomerulus
Filters blood; proteins can’t pass through

16. Composition of Glomerular Filtrate
Water
Small Soluble Organic Molecules
Mineral Ions

17. Proximal Convoluted Tubule
Reabsorbs: water, glucose, amino acids, and sodium.
65% of Na+ is reabsorbed
65% of H2O is reabsorbed
90% of filtered bicarbonate (HCO3-)
50% of Cl- and K+

18. Loop of Henle
Creates a gradient of increasing sodium ion concentration towards the end of the loop within the interstitial fluid of the renal pyramid.
25% Na+ is reabsorbed in the loop
15% water is reabsorbed in the loop
40% K is reabsorbed in the loop

19. Distal Convoluted Tubule
Under the influence of the hormone aldosterone, reabsorbs sodium and secretes potassium. Also regulates pH by secreting hydrogen ion when pH of the plasma is low.
only 10% of the filtered NaCl and 20% of water remains

20. Collecting Duct Allows for the osmotic reabsorption of water.
ADH (antidiuretic hormone)- makes collecting ducts more permeable to water-- produce concentrated urine

21. 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

22. Hormonal Control of Kidney Function

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

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

25. Hormonal Control of Kidney Function

26. INQUIRY List several functions of the kidneys.
What does the glomerulus do?
What are several constitutes you should not find in urine?
What is specific gravity?
What two hormones effect fluid volume and sodium concentration in the urine?
Where are the pyramids located in the kidney?
What vessel directs blood into the glomerulus?
Where does most selective reabsorption occur in the nephron?