Please enable JavaScript.
Coggle requires JavaScript to display documents.
excretion - Coggle Diagram
excretion
-
kidney
ultrafiltration
-blood enters glomerulus through afferent arteriole, which is a branch of the renal artery
-blood leaves the glomerulus through the efferent arteriole which has a smaller diameter than the AA
-this creates a high blood pressure within the glomerulus
-the pressure causes small particles like glucose, amino acids, urea, water and minerals
selective reabsorption
-the glomerulus filtrate moves into the proximal convoluted tubule where ALL glucose and amino acids are reabsorbed by active transport, most mineral salts are reabsorbed by diffusion and active transport and most of the water is reabsorbed by osmosis
-at the loop of henle, some water is reabsorbed via osmosis and some mineral salts are reabsorbed by active transport
-at the distal convoluted tubule, some water is reabsorbed via osmosis, some mineral slats are reabsorbed by active transport
-at the collecting duct, some water is reabsorbed via osmosis
-urea is NOT reabsorbed throughout the nephron. Urea and excess water flows into the collecting duct and passes through the ureter to the bladder
dialysis machine
-blood drawn from the vein in a patients arm is pumped through the dialysis machine which is flled with dialysis fluid
-the walls of the tubing in the machine is partially permeable and allows small molecules like urea and other metabolic products to diffuse out of the patients blood and into the dialysis fluid
-larger molecules like platelets, blood cells and proteins cannot diffuse
-the filtered blood flows back to a vein in the patients arm
adaptation
tubing is coiled, narrow and long to increase SA/V ratio for rapid diffusion of substances
blood flows in the opposite direction of dialysis fluid to maintain the conc. grad of waste products
dialysis fluid contains the same conc. of essential substances as healthy blood to prevent the useful substances from diffusing out of the patients blood
dialysis fluid does not contain metabolic waste products to ensure that the metabolic waste products diffuse out of the patients blood into the dialysis fluid.