Glossary of Tubular Mechanisms
Other Decks By This User
- PCT is what?
- Proximal convoluted tubule
- in the PCT, what is:
100% Glucose/Amino acids
70% Water, Na, and K+
Secreted: 100% PAH
- What happens to filtrate osmolarity at the PCT?
- It does not change.
- What are the 4 steps of reabsorption in the PCT?
- 1. Na/K pump makes [Na] low inside PCT cells; Na is reabsorbed.
2. Na reabsorption makes Glucose/AA move into PCT cell up conc. gradient
3. They move into capillary via facilitated diffusion.
4. Water follows them and gets reabs by SIMPLE diffusion (to maintain osmolarity).
- what type of transport is
-Glu/AA reabsorption from lumen to PCT cell
- -Sodium is primary active transport
-Glu/AA is secondary - uses the energy from Sodium's transport.
- what is the brush border membrane, and where is it?
- the membrane on the inside of the PCT lumen, with increased surface area for enhanced reabsorption.
- What are the 4 (really 5) steps of secretion in the PCT?
- 1. Na/K pump makes low [Na] inside the PCT cell
2a. Na moves from blood to cell.
2b. a-ketoglutarate moves into cell using energy from #2
3. a-ketoglu moves BACK down its conc. gradient into blood, 4. Allows PAH to move UP its conc. gradient. into PCT cell.
- Type of transport when using a-ketoglu's energy to move PAH from blood to PCT cells:
- Tertiary active transport (because a-ketoglu used Na's energy in the first place).
- What occurs in the
-Descending loop of Henle
-Ascending loop of Henle
What general part of the kidney is this?
- Desc: WATER IS REABSORBED.
Asc: Na and Cl are reabsorbed - no water!
-In the renal medulla.
- What are the 3 step of reabsorbption in the Asc loop?
- 1. Na/K pump makes [Na] low inside PCT cells.
2. Na moves in from lumen, Cl also but UP its conc. gradient.
3. Water STAYS in the lumen; the filtrate becomes hypotonic to the outside.
- Why is H2O not reabsorbed in the ascending loop?
- b/c membrane is impermeable, due to TIGHT JUNCTIONS between the cells of the membrane.
- What happens to the ISF during reabsorpn of NaCl in asc loop?
- Becomes concentrated - if it's a juxtamed. nephron, this allows for urine concentration.
- What occurs in the distal convuluted tubule (DCT)?
- -same processes as in the ascending loop - reabsorption of NaCl, but not water.
-Tubule fluid becomes 50 mOsm - more hypotonic.
- when NaCl are reabsorbed, what types of conc. gradients are being fought?
- Na isn't - moves DOWN conc. grd.
Cl is - moves UP its conc. grad.
- what is the distal nephron composed of?
- -Distal Convoluted Tubule (DCT)
- What occurs in the collecting duct?
- Fine tuning of the filtrate by HORMONE ACTION.
- what hormones are responsible for finetuning the filtrate in the collecting duct?
-ADH (antidiarrh. hormone)
- How does Aldosterone work in the collecting duct?
- Steroid action produces more Na/K pumps; causes increased -Sodium reabsorptn
- How does ADH work in the collecting duct?
- Makes membrane H2O-permeable, thus increased H2O reabsorptn.
a. Low ADH makes dilute urine.
b. High ADH = it concentrated.
- how does ADH affect urine volume?
- High ADH = small amounts of concentrated urine.
Low ADH = large amounts of dilute urine.
- What does Alcohol do to ADH?
- well you pee a lot so you have large amts of dilute urine so ADH is low = alcohol inhibits its formation.
You must Login or Register to add cards