Three Functions of Urine Formation Filtration movement of

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Three Functions of Urine Formation • Filtration – movement of fluids from the glomerular

Three Functions of Urine Formation • Filtration – movement of fluids from the glomerular blood to the Bowman’s capsule • Reabsorption – transfer of fluids from nephron back into peritubular capillaries • Secretion – transfer of fluids peritubular capillaries into nephron

Filtration Nutrients flow from glomerulus into Bowman’s capsule due to high blood pressure flow

Filtration Nutrients flow from glomerulus into Bowman’s capsule due to high blood pressure flow (of the artery)

Nutrient Flow of the following nutrients, which ones will flow out of the blood

Nutrient Flow of the following nutrients, which ones will flow out of the blood into the filtrate? Solute water Na. Cl H+ ions amino acids glucose plasma proteins red blood cells (erythrocytes) Glomerulus Bowman’s Capsule?

Reabsorption saves us from having to continuously replenish our body with fluid. • 20%

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

Reabsorption vs. Secretion Reabsorption • carrier/channel proteins move nutrients into interstitial fluid and then

Reabsorption vs. Secretion Reabsorption • carrier/channel proteins move nutrients into interstitial fluid and then back into blood • kidney tissue will only reabsorb a certain level of nutrients Secretion • carrier/channel proteins move wastes from blood to interstitial fluid to nephron

1. Bowman’s Capsule • water and dissolved solutes leave glomerulus; enter Bowman’s capsule water

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

2. Proximal Tubule • selective reabsorption of nutrients (need transporters) • Urine p. H

2. Proximal Tubule • selective reabsorption of nutrients (need transporters) • Urine p. H determined by HCO 3 - reabsorption and H+ secretion HCO 3 -, K+ Na+, Cl. H 2 O amino acids glucose vitamins H+ NH 3

3. Loop of Henle – Descending Limb • only permeable to H 2 O

3. Loop of Henle – Descending Limb • only permeable to H 2 O (osmosis) • impermeable to salt • solutions in tube are being concentrated H 2 O

4. Loop of Henle – Ascending Limb • only permeable to salt (need ionic

4. Loop of Henle – Ascending Limb • only permeable to salt (need ionic transporters) • impermeable to water Na. Cl

5. Distal Tubule HCO 3 Na+, Cl. H 2 O • selective reabsorption of

5. Distal Tubule HCO 3 Na+, Cl. H 2 O • selective reabsorption of nutrients (need transporters) H+ K+ • urine p. H determined by HCO 3 - reabsorption and H+ secretion

6. Collecting Duct • urine formation by concentration nephron fluid • any urea and

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

Kidney Stones • crystallization of some urine solutes • a 2 – 3 mm

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

HOMEWORK Practice Pg 454 #3, 10 Pg 461 #32, 33, 34 Pg 462 #

HOMEWORK Practice Pg 454 #3, 10 Pg 461 #32, 33, 34 Pg 462 # 54, 57 15