Body Fluids and Membrane transport

Question 1

What percent of body mass is water?

Answer 1

60%

Question 2

if you have 42 litres of water in your body, how many would be intercellular?

Answer 2

25

Question 3

if you have 42 litres of water in your body, how many would be extracellular?

Answer 3

17

Question 4

If you have 17 litres of extracellular fluid how many litres are interstitial?

Answer 4

13

Question 5

If you have 17 litres of extracellular fluid, how many litres are plasma?

Answer 5

3

Question 6

if you have 17 litres of extracellular fluid, how many are transcellular?

Answer 6

1

Question 7

what’s intracellular fluid?

Answer 7

fluid within cells

Question 8

what’s extracellular fluid?

Answer 8

fluid outside cells

Question 9

How is Interstitial fluid abbreviated?

Answer 9

ISF

Question 10

What is interstitial fluid?

Answer 10

fluid between tissues

Question 11

What is transcellular fluid?

Answer 11

fluids which have to pass through epithelial cells

Question 12

Give 3 examples of transcellular fluids

Answer 12

any 3 from

• cerebrospinal fluid (in brain)
• urine (kidney and bladder)
• gastrointestinal secretions (saliva, gastric fluid, bile, pancreatic juice)
• sweat
• aqueous and vitreous humors (in eye)
• synovial fluid (in joints)

Question 13

What differs between blood plasma and interstitial fluid?

Answer 13

There’s some protein in plasma but not in interstitial fluid

Question 14

What differs between intracellular and extracellular fluid?

Answer 14

inside cells- sodium high, potassium low- opposite outside cells

Question 15

What are the levels of ions in transcellular fluid?

Answer 15

they vary greatly between different transcellular fluids

Question 16

what are the 3 barriers that fluids pass between?

Answer 16

• plasma membrane
• capillary endothelium
• epithelia

Question 17

What forms the basis of plasma membrane?

Answer 17

lipids

Question 18

what’s the permeability of plasma membrane like and why?

Answer 18

highly selective because nothing water soluble can get across without protein transport

Question 19

what’s the purpose of transport proteins?

Answer 19

allows the uptake of nutrients e.g. glucose and the export of waste products e.g. urea

Question 20

what does a plasma membrane surround?

Answer 20

cells

Question 21

what happens if more water is required inside of a cell?

Answer 21

Cl- and K+ will move into the cell leading to osmosis- the opposite occurs when there’s too much water

Question 22

what maintains a Na+ and K+ concentration gradient in the cell?

Answer 22

K+/Na+ pump

Question 23

What are the 3 types of membrane proteins?

Answer 23

• channels
• carriers
• pumps

Question 24

What do channel membrane proteins do generally?

Answer 24

allow the transport of substances via passive transport

Question 25

what do channel membrane carriers do generally?

Answer 25

allow the passive transport of substances

Question 26

What do channel membrane pumps do generally?

Answer 26

allow the active transport of substances using energy from the hydrolysis of ATP, without requiring a concentration gradient

Question 27

What are the 3 types of carriers?

Answer 27

- facilitator (uniport) - cotransporter (symport) - exchanger (antiport)

Question 28

What do facilitator (uniport) carriers do?

Answer 28

move one type of ion e.g. Na+

Question 29

what do cotransporters (symport) carriers do?

Answer 29

move 2 types of ion, usually oppositely charge ions e.g. Na+ and Cl-

Question 30

what do exchanger (antiport) carriers do?

Answer 30

move 2 types of ion (usually oppositely charged) in 2 directions (1 in 1 out)

Question 31

What is the process of a cell maintaining an electrical gradient?

Answer 31

- K+ is pumped into the cell. Gives a higher concentration of K+ making the cell positively charged - there is a channel which is opened and allows K+ to leave - this causes the inside of the cell to become negatively charged (because there's a negative change from anions in the cell which cannot leave- the K+ can leave) - This makes the resting potential (difference in charge between inside and outside cell due to ion differences) approximately -70mV

Question 32

What process determines water distribution of cell?

Answer 32

osmosis

Question 33

What occurs during osmosis? (3)

Answer 33

- water moves passively (no energy) down gradient - moves to area of high solute concentration - water distributes itself so that the osmmotic pressures inside and outside the cell are equal

Question 34

What is the capillary endothelium?

Answer 34

the very thin layer of specialised cells linking blood vessels

Question 35

how can capillary endothelium vary?

Answer 35

- it can be leaky (highly permeable) e.g. in the kidneys | - it can be non-permeable e.g. the blood-brain barrier

Question 36

What's the ionic concentration difference of ions between blood plasma and ISF like?

Answer 36

low (roughly the same)

Question 37

What's the ionic concentration difference of proteins between blood plasma and ISF like?

Answer 37

high (high in plasma, low in ISF)

Question 38

What pushes blood out of the capillary into ISF from plasma?

Answer 38

Hydrostatic pressure

Question 39

What is Colloid osmotic pressure?

Answer 39

a force that attracts water through endothelial cells from ISF to plasma

Question 40

What is epithelia?

Answer 40

layers of cells covering internal and external surfaces of organs and tissues

Question 41

What's are the roles of epithelia?

Answer 41

- protective/barrier | - important in absorption and secretion e.g. gut nutrients

Question 42

What is the apical membrane of the gut?

Answer 42

epithelial layer inside the guy

Question 43

what is the basolateral membrane of the gut?

Answer 43

epithelial layer on the outside of the gut

Question 44

How does water travel into the small intestine?

Answer 44

- There's a Na+/K+ pump maintaing a gradient. This means that Na+, K+ and Cl- are transported into the cell (K+ is dragged in with the other iond) - this means K+ is in high concentration in the internal epithelial cell - Cl- travels out of the membrane, so water follows by osmosis