1. Kidney Anatomy & Function

2. Organs of the Urinary System
Figure 15.1a

3. Coverings of the Kidneys
Fibrous capsule
Surrounds each kidney, transparent
Perirenal fat capsule
Surrounds the kidney and cushions against blows

4. Regions of the Kidney Renal cortex—outer region
Renal medulla—inside the cortex
Renal pelvis—inner collecting tube
Figure 15.2b

5. Kidney Structures
Renal pyramids—triangular regions of tissue in the medulla
Renal columns—extensions of cortex-like material inward; separate the pyramids
Major/minor calyx —tubes that funnel urine towards the renal pelvis

6. Blood Supply
One-quarter of the total blood supply of the body passes through the kidneys each minute
Renal artery provides each kidney with arterial blood supply
Blood leaves the kidneys through the renal veins

7. Nephron Anatomy and Physiology
The nephron is the structural and functional unit of the kidneys
More than 1 million per kidney
Responsible for forming urine
Main structures of each nephron
Glomerulus (knot of capillaries)
Renal tubule

8. Nephrons
Figure 15.3a

9. Nephron Function is Dependent Upon Blood Flow

10. Nephron Anatomy- Glomerulus AKA Bowman’s Capsule
Figure 15.3c

11. Nephron Anatomy
Figure 15.3d

12. Nephron Anatomy
Renal tubule extends from glomerular capsule and ends at the collecting duct
Glomerular (Bowman’s) capsule
Proximal convoluted tubule (PCT)
Loop of Henle
Distal convoluted tubule (DCT)

13. Nephron Anatomy: Renal Tubule
Figure 15.3b

14. Nephron Anatomy: Renal Tubule
Figure 15.3b

15. Urine Formation

16. 1. Glomerular Filtration
Moves: water & solutes smaller than proteins
Non-selective& passive
Fluid = filtrate
Works b/c there’s high pressure in the capillaries

17. 2. Tubular Reabsorption
Moves: water, glucose, amino acids, & ions into peritubular capillaries (reabsorbed)
Depends on body’s needs
Occurs in entire renal tubule
most in proximal convoluted tubule
Some substances move passively (water  osmosis)
Most move via active transport (glucose, amino acids)

18. 3. Tubular Secretion
Moves: hydrogen ions, potassium ion, & creatinine into filtrate from blood into filtrate to be excreted
Helps get rid of substances not already in filtrate such as drugs or excess potassium
Helps regulate blood pH

19. Filtration, Reabsorption, & Secretion in a Kidney
Figure 15.5

21. Take out a sheet of scrap paper and…
Define filtration and list 3 things filtered out of the blood
Define tubular reabsorption and list 3 things that are reabsorbed
Define tubular secretion and list 2 things that are secreted
Put your name on top and pass it up.

22. Renal Homeostatic Control
Kidneys keep these in normal ranges:
Water pH
Electrolytes
Kidney allow for the removal of
Nitrogen-containing wastes (urea & uric acid)
Creatinine (from muscle metabolism)

23. Major Fluid Compartments of the Body
Intracellular fluid- in cells
Extracellular fluid- NOT in cells
Figure 15.8

25. What is a diuretic?
Hrmmm…

26. Diuretics…
Stuff that makes you pee! Please not in my home.. eew

27. So then anti-diruetic hormone…
Action: causes water to be reabsorbed from filtrate
Where: in the DCT & Collecting Duct
How: adds more aquaporins, therefore more water is reabsorbed
So then why does…
(alcohol prevents ADH from doing its job, you excrete needed water

28. Thirst/Water Regulation

29. pH Balance in Blood & its Regulators
Buffers are the first line of defense  work almost instantaneously
Secondary defenses take longer to work:
Respiratory mechanisms take several minutes to hours
Renal mechanisms may take several days
Bicarbonate 

33. Aldosterone What: Hormone that affects Na+ reabsorption
When released: If blood is diluted & low in volume (from adrenal gland)
Effect: causes more sodium to be reabsorbed fixes concentration… BUT what about the low volume?
Where: Works on DCT and collecting duct

34. Addison’s Disease Description: Inability to produce enough aldosterone
Cause: adrenal glands get attacked by the immune system
Incidence: 3/100,000 of all ages and sexes
s/s: chronic fatigue, muscle weakness, loss of appetite, weight loss, low BP, cravings for salty foods

35. Kidneys help keep Blood Homeostasis by:
Maintaining water
Regulates blood volume & BP; uses ADH
2. Regulate pH (~7.4)
HCO3- and H+
3. Keeping electrolytes in balance
Regulates ion/electrolyte levels; uses aldosterone
4. Excretion of nitrogen-containing wastes
Urea- protein amino acids ammonia  urea
Uric acid  when nucleic acids are broken down
Creatinine doesn’t have nitrogen but still waste from muscle metabolism

38. Contents of Urine Filtrate vs. urine
Should have: sodium & potassium ions, nitrogen-containing wastes, ammonia, bicarbonate ions
Should not have: glucose, blood proteins, RBCs, Hemoglobin, WBCs, bile
Sterile
Colored pH
Aroma
Density/specific gravity

39. Abnormal Substances in Urine
Table 15.1

40. Filtration, Reabsorption, & Secretion in a Kidney
Figure 15.5