A.2 Hydration and nutrition

50-70% of the total body mass is made up of water

is the process of losing body water

normal or good balance of body water content

too much water in the body

not enough water in the body

Increased swear rate during exercise - consequences are dehydration - decrease in performance - increased risk of heat related illness

Sodium Na+, Potassium K+ and Calcium Cl-

Input: drinking, food, metabolic water Output: Urine, sweat, feces Controlled by: antidiuretic hormones and thirst mechanism

organic compounds essential for health

Vitamins Minerals

Water soluble vitamins - excreted in urin Fat soluble vitamins - stored in liver & fat tissue

the only 2 that can be made in the body Vitamin D produced in upper layer of skin with sunlight B3 vitamin niacin is synthesized from amino acid tryptophan

4% body mass 0.001% Functions: bone health, blood production Mineral and trace elements are involved in porcesses that range from maintinging blone and blood health to the release of energy

Calcium, sodium, potassium etc

Thermogergulation: Water helps regulate body temperature through sweating and evaporation. Transport: Blood plasma carries substances around the body Lubrication: Reduces friction and prevents damage. e.g. synovial fluid, tears, saliva

Inside the cells 2/3 of the body water High in potassium

Outside the cells High in sodium Has intersititial fluid

It is the fluid between cells

evaporation from the skin (sweating) evarporation from the respiratory tract (breathing) excretion from kidney (urine) Excretion from large intestines (faeces)

The hypothalamus detects a change in blood water level. It signals the pituitary gland to release ADH, which travels to the kidneys. ADH causes the kidneys to reabsorb more water, helping restore normal levels of water and electrolytes in the blood.