kidneys

Question 1

how does osmoregul;ationm work?

Answer 1

Drop in Water in the Blood
ADH released from pituitary
ADH travels from the loop of Henle
Cell have membrane bound receptors for ADH
ADH binds to receptors
Chain of enzyme controlled reactions occurs inside the cell
Aquaporins sent in vesicles to the cell surface membrane
Aquaporins inserted into cell surface membrane
Walls of collecting duct and Descending Convoluted Tubule more permeable to water
More water moves into the medulla by osmosis
Water potential of the blood rises back to the set level
Brain stops releasing ADH

Question 2

how is water forced out of blood

Answer 2

Pressure in the glomerulus is higher than in the Bowman’s capsule
High pressure forces some water and solutes through the basement membrane and into the Bowman’s capsule
This liquid is now known as the ‘glomerular filtrate’

Question 3

whats in glomerulus ultrafiltrate?

Answer 3

water
amino acids
ions
glucose
urea

Question 4

whats left in blood?

Answer 4

red blood cells
proteins
makes water potential very low so some fluid returns to blood

Question 5

hhpw are fluids reabsorbed in proximal convoluted tubule?

Answer 5

As fluid moves along the nephron, substances are removed
Sodium-Potassium pumps move sodium ions from the cells lining the PCT into the tissue fluid
This reduced the concentration of sodium ions in the cytoplasm
Sodium ions are transported into the cell, along with glucose or amino acids, by facilitated diffusion
As the glucose and amino acid concentrations rise indies the cell, these substances diffuse out of the opposite side of the cell into the tissue fluid
Process may be enhanced by the active removal of glucose and amino acids
Tissue fluids substances diffuse into the blood and are carried away
Reabsorption of salts, glucose and amino acids reduced the water potential in cells and increases it in the tubule fluid
Water will enter cells
Larger proteins can be absorbed by endocytosis

Question 6

how does the loop og henle control concentration of ions and water?

Answer 6

s the fluid moves up the ascending limb, the water potential rises
At the base, sodium and chloride ions diffuse out
Sodium and chloride ions are actively transported out
Wall of the ascending limb is impermeable to water
Fluid loses salt, but not water, when moving up the ascending limb
As the fluid moves down, the water potential falls
Water is lost to surrounding tissue fluid
Sodium and chloride ions diffuse into the tubule