Cellular Physiology

Question 1

Extracellular fluid =

Answer 1

Plasma + Interstitial fluid

Question 2

Interstitum

Answer 2

Space between cells

- connective tissue : collagen + proteoglycan filaments

Question 3

Why is the interstitum a gel?

Answer 3

Normal cells have little free flowing fluid so fluid doesn’t flow to lower regions due to gravity

Question 4

Exchange between interstitial fluid and capillaries

Answer 4

Bulkflow

Question 5

To determine amount of water in each fluid compartment

Answer 5

Dilution of specific markers which have to be physiologically inert and evenly distributed

Question 6

To determine plasma volume

Answer 6

Dye evans blue used as it doesn’t pass across capillary endothelium into interstitial space

Question 7

To determine total body of water

Answer 7

H2O(2) or H2O(3) used

Question 8

To determine extracellular fluid

Answer 8

Inulin or mennitol -> freely passes between circulation and interstitial fluid but doesn’t enter cells

Question 9

Osmotic pressure

Answer 9

Hydrostatic pressure which resists osmosis

Question 10

ICF conc, ECF conc and Nernst mv of Na+

Answer 10

145, 20 , +53

Question 11

ICF conc, ECF conc and Nernst mv of K+

Answer 11

4, 150, -97

Question 12

ICF conc, ECF conc and Nernst mv of Ca2+

Answer 12

1.8, 2x10-4, +120

Question 13

ICF conc, ECF conc and Nernst mv of Cl-

Answer 13

114,3, -97

Question 14

Secondary active transport

Answer 14

Transport of a substance (e.g. glucose) can occur against its electrochemical gradient by coupling its “uphill”
movement to the “downhill” movement of sodium into the cell

Question 15

Uniports

Answer 15

Carrier proteins may bind a specific molecule on one face of the membrane and then transfer it to the other side.

Question 16

Symport

Answer 16

Molecules move in same direction

Question 17

Exocytosis is either

Answer 17

Constitutive (continuous) or regulated

Question 18

Regulated exocytosis occurs by:

Answer 18

1. Entry of Ca2+ through channels in plasma membrane

2. Release of Ca2+ from intracellular stores

Question 19

Pinocytosis

Answer 19

Formation of vesicle traps extracellular fluid

Question 20

Fick’s Law

Answer 20

J = -D x A x (dc/dx)

Amount moved = coefficient x area x conc. gradient

Question 21

Diffusion coefficient becomes ______ as molecular size ____

Answer 21

Smaller, increases

Question 22

Osmotic pressure equation

Answer 22

Pi = MRT where M = molarity

Question 23

Why is osmotic pressure of a salt e.g. NaCL twice of molar conc.

Answer 23

Salts separate into constituent ions

Question 24

Osmolarity

Answer 24

Moles solute per litre of solution

Question 25

Osmolality

Answer 25

Moles solute per kg of water

Question 26

By definition 1 gram mole of a non-dissociating substance in akg of water eerts an osmotic pressure of

Answer 26

1osmolkg-1

Question 27

Total osmolality=

Answer 27

sum of osmolality due to each constituent of solution

Question 28

Blood plasma = X mosmoL-1

Answer 28

300

Question 29

Tonicity

Answer 29

Influence of osmolality on volume of cells