Lecture 2 - Body Fluids and Membrane Transport

Question 1

Name the 7 examples of transcellular fluid from Lec2

Answer 1

Urine, Sweat, Cerebrospinal Fluid, Synovial Fluid, Gastrointestinal Secretions, Aqueous + Vitreous Humours

Question 2

Where is cerebrospinal fluid found in the body?

Answer 2

Brain

Question 3

Where is synovial fluid found?

Answer 3

Some Joints

Question 4

Define Interstitial Fluid (ISF)

Answer 4

Fluid that is outside the blood vessels, but NOT inside a cell (bathes the cells)

Question 5

Describe relative [K+] in different compartments

Answer 5

[K+] is highest in ICF, low in ISF + Plasma

Question 6

Describe relative [Na+] in different compartments

Answer 6

ISF slightly higher than plasma, much lower [Na+] in ICF

Question 7

Describe relative [Cl-] in different compartments

Answer 7

ISF > plasma, MUCH lower in ICF

Question 8

Describe [Protein] in different compartments

Answer 8

1mM in plasma, 0mM in ISF, 4mM in ICF

Question 9

Describe Osmolality in the various Body Fluid compartments

Answer 9

290mOsm in ALL COMPARTMENTS - constant so no net force driving movement of water

Question 10

Which barrier must substances cross to move FROM PLASMA TO ISF?

Answer 10

(Capillary) Endothelium

Question 11

Which barrier must substances cross to move FROM ISF TO TRANSCELLULAR FLUID?

Answer 11

Epithelium

Question 12

Which barrier must substances cross to move FROM ISF TO ICF?

Answer 12

Plasma Membrane

Question 13

Name 4 key functions of plasma membrane

Answer 13

Structural support; physical isolation; regulation of exchange with environment; sensitivity to environment

Question 14

Give BOTH names for each of the three types of carrier in the plasma membrane

Answer 14

Facilitator/Uniport
Co-transporter/Symport
Exchanger/Antiport

Question 15

Three main functions of “these” transport mechanisms (in general)

Answer 15

Uptake of nutrients
Removal of waste
Regulation (of cell pH, volume, [ions] etc)

Question 16

Which pump creates the gradient that allows regulation of cell pH and volume to occur by other passive processes?

Answer 16

The sodium-potassium-ATPase pump (Na+/K+/ATPase)

Question 17

What movement of ions occurs in acid extrusion?

Answer 17

Na+ moves in (now possible due to established gradient); H+ moves out to maintain electrochemical neutrality

Question 18

What movement of ions occurs in base extrusion?

Answer 18

Cl- moves in (down established gradient); HCO3 moves out to maintain electrochemical neutrality

Question 19

What movement of ions occurs in regulatory volume increase?

Answer 19

Na+, K+, Cl- move in; water follows due to osmotic gradient

Question 20

What movement of ions occurs in regulatory volume decrease?

Answer 20

K+ and Cl- channels open, so K+ move out down concentration gradient, Cl- follow to maintain electrochemical neutrality, water follows due to osmotic gradient