electrolyte disorders

Question 1

what is the function of water in the body

Answer 1

• is a solvent for body processes
• removes waste (urine)
• transports nutrients to cells
• body coolant (sweating)
• regulates cell volume

Question 2

what is the percentage of water in males

Answer 2

60%

Question 3

what is the percentage of water in females

Answer 3

55%

Question 4

what is the percentage of water in old people

Answer 4

45%

Question 5

what is the percentage of water in children

Answer 5

75%

Question 6

is there a difference water % due to gender

Answer 6

yes males have more water

Question 7

is there a difference in water due to age

Answer 7

yes children have more water

Question 8

is there a difference in how much water is taken in compared to lost

Answer 8

no, same amount of water taken in is the same as lost (2500ml)

Question 9

what are the functions of electrolytes

Answer 9

• maintains body pH
• regulates water balance by maintaining osmotic pressure
• cofactors in enzyme reactions
• oxidation-reduction reactions
• they correct functioning of muscles and nerves

Question 10

what is osmolality

Answer 10

measure of osmotic concentration

Question 11

what is osmolality expressed as eg, units

Answer 11

moles of solute per kilogram of solvent, mOsm/Kg

Question 12

is osmolality the same in extracellular fluid and intracellular fluid?

Answer 12

yes, they both have an osmotic concentration of 285-295 mOsm/kg

Question 13

from what type of region does water travel from and to

Answer 13

for a region of low osmolality to a region of high osmolality.

Question 14

what is osmosis

Answer 14

this is water balance and is when water moves from an area of high concentration to low concentration through a semi-permeable membrane. uses ATP.

Question 15

what does osmosis prevent from occurring to the cells

Answer 15

bursting

Question 16

what is electrolyte balance

Answer 16

• sodium-potassium pump
• 20-40% of ATP made is used up in trying to regulate this ionic gradient

Question 17

what are the body’s 2 major fluid compartments

Answer 17

intracellular and extracellular fluid

Question 18

what is included in extracellular fluid

Answer 18

• interstitial fluid
• blood plasma

Question 19

in the ECF where does water move to and from

Answer 19

interstitial fluid and blood plasma

Question 20

what is the distribution of water in body compartments

Answer 20

• there is 1/3 of water in extracellular fluid (14l). this is split into 3.5l in plasma and 10.5l in interstitial fluid.
• there’s 2/3 of water in intracellular fluid (28l)

Question 21

how does sodium regulate fluid flux (water moving between membranes) ECF and ICF

Answer 21

• when dehydration occurs sodium ions in interstitial fluid increases which causes water to leave the cell (intracellular fluid) into interstitial fluid (extracellular fluid)
• when water overload occurs the sodium ions decrease which causes water from the interstitial fluid to move into the intracellular fluid. the cells overhydrate

Question 22

is the sodium concentration in interstitial fluid the same as in plasma

Answer 22

yes

Question 23

what is odema

Answer 23

when there’s excessive water in body tissue and it’s visible

Question 24

what will be the immediate effect when there’s a rise in plasma osmolality due to an increase in blood glucose (diabetes mellitus)

Answer 24

• this will cause dehydration because water will move from intracellular fluid to extracellular fluid. this is due to the increase in glucose conc which then increases osmolality
• to repair this the osmoreceptors will detect a change in osmolality causing a stimulation of thirst or causing ADH to be released from the pituitary gland.

Question 25

what is plasma osmolality influenced by

Answer 25

- water deprivation - dietary intake and metabolic activity

Question 26

what detects a change in osmolality

Answer 26

osmoreceptors detect a 1-2% change

Question 27

when osmoreceptors detect a change in osmolality what is stimulated

Answer 27

thirst is stimulated or causes ADH to be produced from the pituitary gland

Question 28

what is the primary control mechanism for body fluid volume

Answer 28

renin angiotensin aldosterone system

Question 29

describe what happens in the renin angiotensin aldosterone system until aldosterone is formed

Answer 29

- when hypovolaemia occurs (low body volume and low blood pressure) this is detected by juxtaglomerular apparatus - JGA cells then renin causing angiotensinogen to be released from liver - this is converted into angiotensin 1 and then the angiotensin converting enzyme from the lungs converts angiotensin 1 into angiotensin 2 - that's then converted into aldosterone via the adrenal cortex

Question 30

what are the effects of the RAA system

Answer 30

- angiotensin 2 causes ADH to be released from the posterior pituitary gland which increases blood volume and this causes blood pressure to increase - angiotensin 2 also increases blood vessel tone which increases blood pressure - aldosterone increases the reabsorption of sodium ions

Question 31

how many amino acids does angiotensin 1 have

Answer 31

10

Question 32

how many amino acids does angiotensin 2 have

Answer 32

8

Question 33

what are the clinical features of dehydration

Answer 33

- increased pulse - decreased skin turgor, urine output, consciousness, blood pressure - eyeballs are soft and sunken - mucous membranes are dry

Question 34

what are the clinical features of overhydration

Answer 34

- decreased consciousness - normal , urine output (or decreased), blood pressure (or increased), eyeballs, mucous membranes - increased skin turgor

Question 35

what are the average sodium levels in an adult man

Answer 35

3700mmol

Question 36

what is the normal plasma sodium conc

Answer 36

135-145mmol/l

Question 37

if sodium plasma conc is below normal range what is it called

Answer 37

hyponatraemia

Question 38

if sodium plasma conc is above the normal range what is it called

Answer 38

hypernatraemia