Chp 2. Water Flashcards
How much water in an adult man body?
60%
Why women have less water as compared to men in their body?
45-55% water because more fat
Fat is drier as compared to muscle
Fat 20% water
Muscle 75% water
Water in babies?
Babies contain more water than adults and elderly have even less
55% ICF
45% ECF (7.5% in bloodstream)
What are the functions of water?
- Building material of cells
- Lubricant
- Regulator of body temperature
- Medium for materials to dissolve/disperse
- Medium for chemical reactions in cells (esp. Hydrolytic)
- Transport medium for nutrients and wastes
From where did the body get water?
- Daily diet (750 to 1000ml) 25-35%
- Water produced in metabolic reactions 10-15%
- Water taken as fluids/beverages 50%
How much water is produced when 1 g of carbohydrate is oxidized?
0.6 g
How much water is produced when 1 g of fat is oxidized?
1.07 g
How much water is produced when 1 g of protein is oxidized?
0.41 g
How much water produced by liberation of 1 kcal heat energy?
100 to 140 ml
How water is lost from the body?
- Lungs (respiration)
- Skin (insensible perspiration and sweat)
- Digestive tract (faeces)
- Kidneys (urine)
How much water is lost through respiration?
400 ml
How much water is lost through skin in all conditions?
400 ml
Insensible loss of water is influenced by?
Temperature and Humidity
How much water is lost through faeces?
100 to 200 ml
How much water is lost through urine?
1000 to 2000 ml
How much water does the kidneys filter per day?
180 L
What happens when water losses in body are greater than gains?
Body fluids concentrate> decrease in plasma volume and increase in osmotic pressure > thirst response is triggered in brain > withdrawal of water from cells in mouth and throat > causing dryness and stimulate thirst
High osmotic pressure of blood > retention of water by kidneys ADH and Aldosterone
How water intoxication occurs?
It occurs when water content of body increase without proportional increase in the electrolytes > nausea, headache, in coordination of movements and muscular cramps
Water intake depends on?
Diet
Age
Climate
Activity etc.
How diet influence water intake?
More food intake» more water intake
1ml for each Calorie expended or consumed
More water when diet is rich in protein and salt
Water requirements increases with__________
Age
How climate or weather conditions affect water intake?
More water in hot weather
Temperate climate min 900 ml max 2000ml required by sedentary man
Much more need in tropical region due to increase in temp, humidity and activity
