The Function of the Kidney 1 Flashcards
What is the difference between the afferent and efferent arterioles? Why is this?
The afferent arteriole has a larger diameter than the efferent arteriole.
This creates a high pressure in the glomerulus.
What is filtered out of the blood?
Water Amino acids Glucose Urea Inorganic mineral ions (Na, Cl, K)
What is the relative molecular mass that the mesh of the basement membrane prevents from passing through?
The mesh acts as a filter to prevent passage of molecules with a relative molecular mass of greater than 69,000
Why will some of the water move back into the blood after being filtered out?
The water potential in the glomerulus lowers because of the movement of water into the proximal convoluted tubule. Through osmosis water moves back into the glomerulus capillary to balance the water potential.
Where does selective reabsorption occur?
In the proximal convoluted tubule
What do the sodium-potassium pumps do in selective reabsorption and which cells have them?
The Na-K pumps are found in the cells lining the proximal convoluted tubule. They pump Na ions out of the cells in the lining and into the tissue fluid -> blood plasma.
What occurs as a result of the Na-K pumps in action?
Concentration of sodium ions in the cell cytoplasm decreases, creating a concentration gradient.
How does Na move?
Through cotransporters.
What follows the sodium as a result of the concentration gradient that has been created?
Water follows.
What else goes through the cotransporters?
Sodium ions diffuse into the cell through a cotransport protein, the sodium brings with it glucose or amino acids at the same time.
How are small proteins reabsorbed in selective reabsorption?
Small proteins are reabsorbed through endocytes.
How are the cells lining the convoluted tubule adapted for selective reabsorption?
The cells have microvilli which increase the surface area of the membrane for active transport and facilitated diffusion. This all makes them closer to the lumen.
