Excretory System

Front 1

Kidney Function

Back 1

1. excrete wate products: urea, uric acid, ammonia, phosphate. 2. maintain homeostasis of the body fluid volume and solute composition and 3. help control plasma pH.

Front 2

Kidney Structure:

Back 2

Outer cortex, inner medulla.

Front 3

Outline of the Excretory System

Back 3

Bowman's Capsule. Proximal tubule. Loop of Henle. Distal Tubule. Collecting Tubule. Collecting Duct.

Front 4

Nephron

Back 4

Functional unit of the kidney.

Front 5

Glomerulus

Back 5

First capillary bed of the nephron. Contains fenestrations.

Front 6

Renal corpuscle

Back 6

Bowman's capsule and the glomerulus

Front 7

Hydrostatic pressure at beginning of excretory system

Back 7

Forces plasma through feestrations into bowman's capsule. Fenestrations filter this fluid - filters out blood cells, large proteins.

Front 8

Filtrate

Back 8

Fluid that enters bowman's capsule. Moves from bowman's capsule into the proximal tubule

Front 9

Proximal tubule

Back 9

location of most reabsorption. Reabsorption of: glucose, proteins, other solutes. Transport proteins cause this reabsorption to occur. Transport maximum. More solute than that, enters into the urine. Other solutes are not actively reabsorbed, but are reabsorbed by passive or facilitated diffusion. Osmotic gradient allows for the rabsorption of water. Drugs, toxins, other solutes are secreted into the filtrate. Net Result: reduce amount of filtrate in the nephron Change solute composition without changing osmolarity .

Front 10

Hydrogen ions at proximal tubule

Back 10

secreted through antiport system with sodium, driven by sodium concentration gradient. Moves in opposite direction from sodium movement.

Front 11

Loop of Henle

Back 11

Dips into the medulla. Function: increase solute concentration and the osmotic pressure of the medulla. Water passively diffuses out of the loop of henle into the medulla. Descending loop of Henle: low salt permeability. This causes osmolarity of filtrate to go up. As filtrate rises out of the medulla, salt diffuses out of ascending loop of henle. first passively, then actively. Ascending loop of henle - nearly impermeable to water. Capillary bed surrounds the loop of henle - helps maintain concentration of medulla.

Front 12

Distal tubule

Back 12

Reabsorbs sodium and calcium while secreting potassium, hydrogen ions, and hco3-. Aldosterone acts on d. tubule - increases sodium and potassium membrane transport proteins. Net effect: lower the filtrate osmolarity.

Front 13

Collecting tubule

Back 13

part of the distal tubule. Here ADH increases permeability of cells to water. Water flows from the tubule, concentrating the filtrate.

Front 14

collecting duct

Back 14

receives contents of the distal tubule. Carries filtrate into osmotic medulla. Impermeable to water, but sensitive to adh. With adh - becomes permeable to water. Allows it to passively diffuse into medulla - concentrates the urine.

Front 15

Juxtaglomecular apparatus

Back 15

monitors filtrate pressure in the distal tubule. Results in stimulation of adrenal cortext to secrete aldosterone. This acts on distal tubule - stimulating formation of membrane proteins that absorb sodium and secrete potassium.