hydration/ water

Question 1

whys body water status important

Answer 1

forms saliva (digestion)
keeps mucosal membrane moist
allows bodys cells to grow, reproduce and survive
flushes body waste, mainly urine
lubricates joints
water is the major component of most body parts
needed by the brain to manufacture hormones and neurotransmitters
regulates body temperature (sweating and respiration)
acts as a shock absorber for brain and spinal cord
converts food to components needed for survival - digestion
helps deliver oxygen all over the body

Question 2

sweat rates affected by

Answer 2

body size
absolute vo2 (fitter = more water)
aerobic fitness
heat acclimatization
environment

Question 3

sweat calcs

Answer 3

sweat loss (L) = (change in mass + fluid intake) - urine
sweat rate (L/hr) = sweat loss/ time in hours

Question 4

dehydration

Answer 4

loss of solutes/ reduced blood vol
change in osmotic pressure
cells lose water and shrink

Question 5

dehydration effecting performance

Answer 5

performance decreased when dehydration exceeds 1-3% of body weight

Question 6

dehydration calcs

Answer 6

percentage = (mass loss/ pre-mass) x 100

Question 7

water balance

Answer 7

input=output
homeostatic mechanisms
water inputs
- food
- fluid
- metabolism
water output
- urine
-faeces
- skin
-lungs

Question 8

plasma membrane

Answer 8

separates intercellular fluid from surrounding interstitial fluid

Question 9

blood vessel wall

Answer 9

divide interstitial fluid from plasma

Question 10

electrolytes

Answer 10

substance that produces an electrically conducting solution when dissolved in polar solvent
separate into cations and anions Na+, Cl-, Mg 2+, Ca 2+, K+
control osmosis of water
maintain pH balance
carry electrical current
cofactors

Question 11

electrolyte imbalance

Answer 11

electrolyte content of sweat is low vs body fluids
dehydration via sweat concentrates Na+ and Cl- in body fluids
plasma Na+ and K+ conc remain
sweat loss of 5-6 L or less causes only small amount of electrolytes lost from relatively large body store

Question 12

factors affecting daily water needs

Answer 12

climate
clothing
activity levels

Question 13

organic body fluids

Answer 13

glucose
amino acids
fatty acids
hormones
enzymes

Question 14

inorganic body fluids

Answer 14

sodium
potassium
calcium
magnesium
chloride
phosphate
sulphate

Question 15

osmosis

Answer 15

through a partially permeable membrane from low solute to high solute concentration
passive transport
solvent = H2O
solute = glucose, electrolytes

Question 16

electrolytes in extracellular fluid

Answer 16

most common: sodium ion
- muscle contraction
- impulse transmission
- fluid and electrolyte balance
lest common: chloride ion
- regulates osmotic pressure
-forms HCl

Question 17

electrolytes in intracellular fluid

Answer 17

most common: potassium ion
- resting membrane potential
- action potential
- maintain intracellular volume
- regulation of pH
lest common : phosphate anion
- parathyroid hormone regulation
- blood calcium levels

Question 18

osmolality

Answer 18

number of osmoles of solute per kg of solution

Question 19

osmolarity

Answer 19

number of osmoles of solute in litre of solution
-measure body electrolyte-water balance
- plasma, saliva or urine sample

Question 20

euhydration

Answer 20

state of normal body water level
plasma osmolality = 285-290 mOsmol/kg
isotonic osmotic equil

Question 21

hypohydration in cells

Answer 21

state of reduced body water level3
urine osmolality > 700 mOsmol/kg (high=low water levels)
max urine osmolality in severe dehydration = 1200 mOsmol/kg
hypertonic solution

Question 22

hyperhydration

Answer 22

state of elevated body water level
urine osmolality < 700 mOsmol/kg
min = 50 mOsmol/kg
hypotonic solution

Question 23

considerations for optimal drink

Answer 23

absorb rapidly
cause little/ no gastrointestinal distress
maintain extracellular fluid vol and osmolality
offers potential to enhance exercise performance