Substances involved in water and electrolyte balance

Question 1

The circulation of water in organism is centrally controlled by what

Answer 1

Thirst centre in hypothalamus

Question 2

What is the 24 hour fluid intake requirement of the organism (ml/kg)

Answer 2

40-132 ml/kg

Question 3

What does the 24 hour fluid intake requirement depend on?

Answer 3

Animal species
Gender
Age
Physiological consumption
Lactation

Question 4

What does the water content of organism depend on?

Answer 4

Fat tissue content
- The more fat, less water
Age
- Young animals have higher levels

Question 5

Water content of different tissues

Answer 5

1. Muscle tissue: 50%
2. Skeleton: 14%
3. Blood: 5%

Question 6

Extracellular fluid includes what

Answer 6

Blood (plasma volume),
Interstitial lymph fluid,
Transcellular fluid
and fluid present in connective tissue and bone.

Question 7

Transcellular fluid

Answer 7

Fluid contained within cavities of organism
- Pleural cavity, GI tract, peritoneal cavity etc.

Question 8

Skin’s role in water balance

Answer 8

Important in regulation of water content
Contains up to 70% of water (of its own weight)
Water reservoir, storage of Na and Cl ions

Question 9

Primary cations of the organism

Answer 9

Sodium
Potassium
Calcium
Magnesium

Question 10

Primary anions of the organism

Answer 10

Chlorine
Hydrocarbonate
Phosphate
Sulfate

Question 11

Objectives of cations and anions

Answer 11

1. Ensuring osmolarity of body fluids
2. Forming bioelectric membrane
   potentials
3. Act as the catalysts of metabolism
4. Determine the pH of bodily fluids
5. Stabilise tissue
6. Form energy depots
7. Participation in blood coagulation

Question 12

Objectives of sodium

Answer 12

1. Ensuring osmolarity of extracellular
   compartment
2. Impact volume of intracellular
   compartment - depending on
   concentration of sodium in plasma
3. Participation in formation of
   bioelectric potential of membrane

Question 13

Objectives of potassium

Answer 13

1. Participation in utilisation of carbohydrates
2. Necessary for synthesis of proteins
3. Participation in nerve-muscle stimulus transmission
4. Participates in activity of muscle, heart, CNS and kidney cells

Question 14

Objectives of calcium

Answer 14

1. Structural element in the composition
   of bones and teeth
2. Impacts the stimulation of muscles
   and nerves
3. Impacts the permeability of
   membranes
4. Participation in blood coagulation as a
   coagulation factor

Question 15

Objectives of magnesium

Answer 15

1. Participation in fermentation process
2. Cell regeneration
3. Utilisation of oxygen
4. Glycolysis
5. Suppresses nerve signal transmission
   (curare-like effect)
6. Dilates blood vessels, facilitates
   fibrinolysis

Question 16

Objectives of Chlorine

Answer 16

1. Primary plasma anion
2. Participates in formation of
   membrane potential

Question 17

Objectives of phosphate

Answer 17

1. Makes up bone structure together
   with calcium
2. Participates in carbohydrate
   metabolism
3. Participates in phosphate buffer
   system