1. Renal System

2. Role of Kidney renal system – referring to the kidney blood filtration
waste excretion
acid / base balance
blood pressure regulation
hormone secretion

3. Kidney Blood Flow Blood enters the kidney through the renal artery.
renal arteries stem from the:
Filtered blood exits the kidney through the renal vein.
renal veins flow into the:

4. Kidney Blood Flow

5. Blood and the Nephron
Renal artery blood is filtered through nephrons. About a million nephrons make up the kidney. Nephrons collect liquid to be excreted. Fluids are exchanged between the nephron before blood is returned to renal vein.

6. Blood Flow The renal artery is split into afferent arterioles.
blood brought to glomerulus (a capillary bed)
blood leaves through the efferent arterioles
no veins involved
Efferent arterioles are the beginning of a network of peritubular capillaries, that wrap around the nephron.

7. Glomerulus and Bowman’s Capsule

8. Nephron

9. Nephron
Nephrons begin surrounding the glomerulus with the Bowman’s capsule structure.
What is the pathway taken by the waste solution once it is collected by the Bowman’s capsule?

10. Kidney Structure
renal cortex – outside of kidney; location of Bowman’s capsule renal medulla – middle of kidney; location of loop of Henle renal pelvis – location of the ends of collecting ducts

11. Urine Flow
Urine leaves the renal pelvis through the ureters and travels to the bladder. Fluid leaves the body through the urethra.

12. Urinary Tract

13. Nephron Structure proximal tubule efferent arteriole glomerulus
distal tubule
Bowman’s capsule
collucting duct
Loop of Henle
afferent arteriole

14. Urinary System aorta renal cortex renal artery renal vein
inferior vena cava
renal cortex
renal artery
renal vein
renal medulla
kidney
ureter
bladder
renal pelvis
nephrons
urethra
ureter

15. Urine Formation

16. Three Functions of Urine Formation
filtration –
reabsorption –
secretion –

17. Filtration
Nutrients move from glomerulus into Bowman’s capsule due to high blood pressure (65 mm Hg; normal ~ 25 mm Hg)

18. Glomerulus  Bowman’s Capsule?
Nutrient Flow
Solute
Glomerulus  Bowman’s Capsule?
water
yes
NaCl
H+ ions
amino acids
glucose
plasma proteins no
red blood cells (erythrocytes)
platelets

19. Reabsorption
Reabsorption saves us from having to continuously replenish our body with fluid.
20% of fluid flowing into kidney is filtered into nephrons
less than 1% of nephron fluid is used to make urine

20. Reabsorption vs. Secretion
protein transporters move nutrients molecules from nephron into the blood
protein transporters move wastes from blood to nephron

21. 1. Bowman’s Capsule
water and dissolved solutes leave glomerulus; enter Bowman’s capsule
water
Na+ H+
Cl-
glucose
amino acids
vitamins
minerals
urea
uric acid

22. 2. Proximal Tubule
HCO3-, K+
Na+, Cl-
H2O
amino acids
glucose
vitamins
selective reabsorption of nutrients (need transporters)
pH determined by HCO3- reabsorption and H+ secretion H+
NH3

23. 3. Loop of Henle – Descending Limb
only permeable to H2O (osmosis)
impermeable to salt
fluids in tube are being concentrated
H2O

24. 4. Loop of Henle – Ascending Limb
only permeable to salt (need ionic transporters)
impermeable to water
NaCl

25. 5. Distal Tubule
selective reabsorption of nutrients (need transporters)
pH determined by HCO3- reabsorption and H+ secretion
HCO3-
Na+, Cl-
H2O H+
NH3 K+

26. 6. Collecting Duct urine formation by concentration nephron fluid
any urea and urine that is reabsorbed is less than that was filtered into nephron
NaCl
urea
water

28. Kidney Stones crystallization of some urine solutes
a 2 – 3 mm stone can obstruct flow to the ureter
Treatment:
increased water consumption
surgery