body fluids

Question 1

define electrolyte

Answer 1

a substance that separates into cations and anions when dissolved in water to produce an electrically conduction solution

Question 2

what are the fluid compartments in the body?

Answer 2

ICF

ECF - plasma and interstitial fluid

Question 3

how much of the body is water?

Answer 3

60%

Question 4

how much of the body weight is ECF?

Answer 4

20%

Question 5

how much of the body weight is ICF?

Answer 5

40%

Question 6

what electrolytes are high in the ECF?

Answer 6

Na+ and Cl-

Question 7

what electrolytes are high in the ICF?

Answer 7

K+

Question 8

what forces determine the movement of water between fluid compartments?

Answer 8

osmotic pressure

hydrostatic pressure

Question 9

what is osmotic pressure?

Answer 9

the pressure that’s sufficient to prevent the uptake of water
related to the number of particles in the solution

Question 10

what is osmolality?

Answer 10

a measure of the number of osmotically active particles in solution - how much solute is free in solution

Question 11

what are the three main sources of osmolarity in the body?

Answer 11

charged macromolecules and their counter ions
smaller metabolites and their counterions
small inorganic ions

Question 12

how do animal cells control their osmolarity?

Answer 12

actively pumping out inorganic ions so that their cytoplasm has a lower conc than the ECF

Question 13

what toxins inhibit the Na+/K+ ATPase?

Answer 13

oubain

Question 14

what is tonicity?

Answer 14

the ability of an extracellular fluid to make water move into or out of a cell

Question 15

what determines tonicity?

Answer 15

the solutes that do not enter the cell bc only these can exert oncotic pressure

Question 16

define colloid

Answer 16

a large molecular weight particle present in a solution

Question 17

what percent of water taken in is from food and drink?

Answer 17

90%

Question 18

what percent of water taken in is from metabolism?

Answer 18

10%

Question 19

how can water be lost in the body?

Answer 19

sweat
respiration
faeces
urine

Question 20

what does aldosterone do?

Answer 20

controls reabsorption of sodium in the dct

Question 21

what does ADH/vasopressin control?

Answer 21

water reabsorption in the collecting duct

Question 22

explain the mechanism to correct low blood volume

Answer 22

detection by JGA
secretes renin
triggers angiotensin II release
contrists arterioles
releases aldosterone
increases Na+ and water reabsorption

Question 23

what is hyponatremia?

Answer 23

decrease in plasma electrolytes

Question 24

what causes hyponatremia?

Answer 24

congenitive heart failure or kidney failure

over hydration

Question 25

what is hypernatremia?

Answer 25

increase in plasma electrolytes

caused by dehydration

Question 26

explain ecstasy induced hyponatraemia

Answer 26

body retains water and secretes sodium
causes swelling of the brain (angiodema)
women more likely to be affected bc of oestrogen