How are the proximal convoluted tubules adapted to reabsorb substances into the blood? (3 ways)
They have epithelial cells that have: 1) Microvilli with large SA for reabsorption 2) Infoldings at bases for large SA from epithelial cells to capillaries 3) Many mitochondria - ATP for active transport.
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How are ions reabsorbed into the blood from the PCT? (4 steps)
1) Na+ actively transported out of epithelial cells into blood capillaries, lowering their Na+ conc. 2) Facilitated diffusion of Na+ from lumen to cells. 3) Co - transport of glucose/amino acids/ions into cells 4) Diffusion of molecules into blood.
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What is the difference in permeability of the ascending and descending limbs to water?
How are the cells lining the ascending limb adapted to active transport of Na+?
Many mitochondria for ATP production.
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What happens to water leaving the descending limb?
Enters the blood capillaries by osmosis and is carried away.
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How are the walls of the DCT adapted for reabsorption of material from the filtrate? (2 ways)
1) Microvilli for large SA 2) Many mitochondria for ATP production. Allows active transport of ions into the blood.
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What is the main role of the DCT?
Makes final adjustments to the water and salts that are reabsorbed and controls blood pH by selecting which ions to reabsorb (selectively permeable walls).
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Other cards in this set
Card 2
Front
How are ions reabsorbed into the blood from the PCT? (4 steps)
Back
1) Na+ actively transported out of epithelial cells into blood capillaries, lowering their Na+ conc. 2) Facilitated diffusion of Na+ from lumen to cells. 3) Co - transport of glucose/amino acids/ions into cells 4) Diffusion of molecules into blood.
Card 3
Front
What is the difference in permeability of the ascending and descending limbs to water?
Back
Card 4
Front
How are the cells lining the ascending limb adapted to active transport of Na+?
Back
Card 5
Front
What happens to water leaving the descending limb?
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