Cell Homeostasis Flashcards Preview

BMS 242 Core Physiology and Pharmacology > Cell Homeostasis > Flashcards

Flashcards in Cell Homeostasis Deck (50)
Loading flashcards...
1

What are the normal intracellular and extracellular conditions for sodium

high extracellular, low intracellular

2

What is the function of the thick ascending limb in the loop of Henle

reabsorption of Na+ and Cl-

3

What are the properties of the apical membrane of the thick ascending limb

impermeable to water, ammonia and protons

4

What does the reabsorption of NaCl across the TAL create

trans-epithelial osmotic gradient

5

What is the trans-epithelial osmotic gradient responsible for

counter current multiplication

6

Activity of what transporter depends on the inward Na gradient

NKCC

7

What happens if intracellular sodium levels rise

diuresis, increased sodium and chloride in the urine

8

Describe the normal chemical and electrical gradient for sodium movement

very large for sodium to move into the cell

9

What problems occur if the sodium chemical and electrical gradient are reduced

action potential propagation problems, slower action potentials

10

What controls intracellular Na+

Na/K ATPase pump

11

What does Na/K ATPase require for its action

ATP phosphorylation

12

What happens to the Na/K ATPase when 3 sodiums bind

phosphorylation

13

What does phosphorylation of the Na/K ATPase pump trigger

conformational change

14

What is the effect of this conformational change on the Na/K ATPase

shifts the binding domain from intracellular to extracellular side - moving Na+ out

15

What does the function of the sodium potassium ATPase pump depend on

ATP, intracellular sodium and extracellular potassium

16

What is the Na/K+ ATPase inhibited by

cardiac glycolysis, ouabain and digoxin

17

What is the net effect on the membrane potential of the Na/K ATPase

makes inside of the cell more negative

18

What does accumulation of K inside the cell create

driving force for potassium to leave the cell - making the cell more negative

19

What are the normal intracellular and extracellular conditions for calcium

high extracellular calcium, low intracellular calcium

20

Why is calcium regulation important

calcium is an important second messenger

21

How does the cell maintain low intracellular calcium

Na/Ca exchanger, Ca ATPase

22

What does the Na/Ca exchanger transport

exchanges extracellular sodium for intracellular calcium

23

True or False - the Na/Ca exchanger is electrogenic

True

24

What is the SLC8

solute co transporter type 8

25

How many transmembrane spanning domains does the SLC8 have

10

26

What is the Na/Ca exchanger a member of

SLC8 gene family

27

How does the SLC8 gene family allow different functions in different cell types

changing its splice variant

28

What family is the Ca ATPase a member of

P-Type ATPase family

29

How many types of ATPases are there

2

30

What are PMCAs

plasma membrane calcium pumps

31

What is the function of PMCAs

pump Ca2+ across the plasma membrane out of the cell

32

What is the function of SERCA

pump Ca2+ out of cytoplasm into organelles

33

What is SERCA

calcium pumps found on sacroplasmic or ER membranes

34

What are SPCA

Ca2+ pumps on golgi apparatus

35

How does calcium signalling move calcium

across PM into cytoplasm, or out of storage organelle into cytoplasm

36

Where are voltage operated Ca chanels found (VOCC)

excitable cells

37

What are VOCCs activated by

depolarisation

38

Where are receptor operated Ca channels (ROCC) found

secretory cells and nerve terminals

39

What are ROCCs activated by

binding of agonist

40

Example of a ROCC

NMDA receptor

41

Where are mechanically activated Ca channels found

many cells

42

What do mechanically activated Ca channels respond to

cell deformation

43

What is an example of mechanically activated Ca channels

stretch activated channels

44

What activates store operated calcium channels

depletion of calcium stores

45

What are the two classes of calcium channels in store membranes

IP3 receptors, ryanodine receptors

46

What receptors involved in calcium signalling are associated with excitable cells

ryanodine

47

Which receptor involved in calcium signalling is biphasic

ryanodine

48

What happens to the SOCCs when IP3 is formed

open and calcium moves out into the cytoplasm

49

How are the calcium levels restored

SOCCs open and allow calcium to move in and refill the store

50

Name another protein involved with calcium movement

Stim and Orai channels