loop of henle Flashcards
what happens to the filtered glucose and amino acids
-completely reabsorbed back into the blood
-as filtrate passes through the proximal convoluted tubule
describe the processes of reabsorption
-initialy facilitated diffusion
-and then by active transport into the cells lining the PCT
-water absorbed by osmosis
what else is reabsorbed at the PCT
mineral ions
water (by osmosis)
-active transport of glucose and amino acids into the blood from pct lowers water potential in the blood
What causes the diagnosis of diabetes
-the presence of glucose in urine
-due to carrier proteins being unable to reabsorb all filtered glucose by active transport
-as blood glucose conc is too high
describe the structure of the PCT that allow reabsorption of substances
-microvilli-large sa
-numerous mitochondria to provide atp from aerobic respiration for at
-carrier proteins in cell surface membrane for active transport
what does the loop of henle do
removes water from the filtrate , allowing the production of concentrated urine
describe step one in the loop of henLe
NA and Cl ions are actively trans[orted out of the ascending limb (thick right)
what does it mean when the NA and Cl ions are actively transported out of the ascending limb
it creates a high concentration of ions in the tissues of the medulla
describe step 2 od the loop of henLe
sodium and chlorine ions actively transported out into the tissues of the medulla creates a high concentration of ions in the tissues of the medulla
What does the high concentration of ions in the tissues of the medulla mean
creates a low water potential
describe step 4 of the loop of henLe
water moves out of the filtrate to the medulla by osmosis
what does the movement of water into the medulla mean
means that the filtrate is very concentrated
describe step 5
the filtrate then passes through the distal convoluted tube
-down the collecting duct
-ADH increases the permeability of these structures to water
Describe the steps of the DCT , and ADH
1) ADH attatches to specific receptors on the cell of the DCT and collecting duct which stimulates aquaporins to move to the cell surface membranes of these cells
2) aquaporins enable more water to be reabsorbed from these structures by osmosis down a water potential gradient
3) the water that leaves the distal tubule and collecting duct passes into the medullary tissue fluid (lower water potential) and then into the surrounding blood capillaries whip eventually join to form the renal vein
4) the increase in concentration of sodium and chloride ions down the medulla ensures that there is always a lower water potential in the medulla through which the filtrate in the collecting duct travels .Therefore more water can be reabsorbed when required by osmosis
5) the amount of water reabsorbed from the DCT and the collecting duct depends on the water potential of the blood
6) the water potential of the blood and the body fluids must be maintained at a constant level
