deck_504426

Question 1

Give the free ion distribution of Na+, K+, Ca2+ and Cl- inside the cell

Answer 1

Na+ - 10mMK+ - 160mMCa2+ - 1 x 10^-4mMCl- - 3 mM

Question 2

Give the free ion distribution of Na+, K+, Ca2+ and Cl- outside of the cell

Answer 2

Na+ - 145 mMK+ - 4.5mMCa2+ - 1.5mMCl- - 114 mM

Question 3

Describe the process of the Na+/K+-ATPase pump

Answer 3

• Exchanges 3 intracellular Na+ for extracellular 2K+* Creates high intracellular K+ * Antiport protein

Question 4

What does the Na+/K+-ATPase pump drive?

Answer 4

Processes of secondary active transport via formation of Na+ concentration gradient

Question 5

Why must levels of Ca2+ in cells be controlled?

Answer 5

High Ca2+ toxic to cells

Question 6

What is SERCA? Describe its process (4)

Answer 6

• Antiport protein * High affinity low capacity for Ca2+ * Accumulates Ca2+ into the Sarcoplasmic reticulum/Endoplasmic Reticulum in exchange for H+ * Primary active transport: ATP hydrolysis

Question 7

What is PMCA?

Answer 7

• Antiport protein * High affinity, low capacity for Ca2+ * Intracellular Ca2+ exchanged for extracellular H+ (expels Ca2+) * Primary active transport: ATP hydrolysis

Question 8

What type of active transport is demonstrated by NCX? What is its normal role?

Answer 8

• Secondary active transport* Expelling Ca2+ during cell recovery

Question 9

What is the process of transport for NCX?

Answer 9

• 3 Na+ into cell, 1 Ca2+ out of cell* Electrogenic - current flows in direction of Na+ gradient

Question 10

What is NCX dependent on?

Answer 10

Membrane potential

Question 11

What happens to NCX in depolarised cells?

Answer 11

The normal mode of operation is inhibited and reversed, so Ca2+ enters cell.

Question 12

What role does NCX have in ischaemia?

Answer 12

1. ATP depleted due to lack of O22. Sodium pump inhibited – no movement of Na+ out of cell3. NCX reverses, as outside negative: Ca2+ in, 3 Na+ out4. High Ca2+ toxic to cell – activates potent enzymes

Question 13

What is the process of NHE cotransporter?

Answer 13

Na+ in, H+ out Gradient follows Na+ - no ATP hydrolysis

Question 14

What does the NHE contransporter regulate?

Answer 14

o Cell volume i.e. cell swelling: increase ion efflux – water follows by osmosis, cell shrinkage: increase ion uptakeo pH

Question 15

What is the NHE cotransporter activated and inhibited by?

Answer 15

• Activated by growth factors/ inhibited by amiloride

Question 16

What is NBC?

Answer 16

• Na+ and HCO3- into cell, Cl- out* Gradient follows Na+

Question 17

What occurs in cell when buffering exceeded?

Answer 17

Control of cellular pH is given to variety of plasma membrane transporters

Question 18

What is acidification of a cell opposed by?

Answer 18

• Expelling H+ via the Na+/H+ exchanger (NHC) or the inward movement of bicarbonate via NBC.

Question 19

What is alkalisation of a cell opposed by?

Answer 19

• Expelling bicarbonate via the anion exchanger* HCO3- out, Cl- in

Question 20

What is AE?

Answer 20

Anion exchangeHCO3- out, Cl- in.

Question 21

Why are electroneutral transport ions used to mediate osmotic strength of cytoplasm?

Answer 21

Allows osmotic strength to be varied without effect on membrane potential

Question 22

What do cells do in response to swelling? What happens in shrinkage?

Answer 22

Extrude ions (Na+, K+, Cl-) Influx ions (Na+, K+, Cl-) Water follows ions down osmotic gradients

Question 23

Give three ways cell swelling can be resisted

Answer 23

Conductive transportersContransport systemsSolute molecules exprelled

Question 24

Why is all bicarbonate filtered into proximal tubule of the kidney reabsorbed?

Answer 24

Retains base for pH buffers

Question 25

what is the main enzyme involved in bicarbonate reabsorption?

Answer 25

Carbonic anhydrase, which breaks down carbonic acid to H20 and CO2.

Question 26

Write out bicarbonate reabsorption process

Answer 26

Got it?

Question 27

What is often the first line of treatment for mild hypertension?

Answer 27

Renal control of circulating Na+ concentration

Question 28

What are the two transporters involved in the thick ascending limb, between the proximal tube lumen and the epithelial cells

Answer 28

NKCC2and ROMK

Question 29

What does NKCC2 do in the kidney?

Answer 29

Transfers Na+, K+ and 2Cl- into epithelial cells of proximal tubule

Question 30

What does ROMK do?

Answer 30

Absorbs K+ from epithelial cells of proximal tube into lumen

Question 31

What are the three transporters found between kidney epithelial cells and capillaries of thick ascending limb?

Answer 31

KCICT, CIC - Kb, Na pump

Question 32

What does KCICT pump?

Answer 32

K+ and Cl- from epithelial cells to capillaries

Question 33

What does CIC - Kb pump?

Answer 33

Cl - into capillary from epithelial cells

Question 34

What does the Na pump do?

Answer 34

Sodium potassium pump, 3 Na+ out, 2 K+ in

Question 35

What drug can be used to inhibit reabsorption of Na+ from proximal tube of kidney in thick ascending limb?

Answer 35

Loop diuretic, inhibits NKCC2

Question 36

What two things can Na+ reabsorbtion inhibtors treat?

Answer 36

Hypertension and Oedema