NST10 Midterm 3 Notes
© Eddie Lo, Fall 2007
Nutritional Science 10 Lecture Outline
Midterm 3 Notes
Functions in Water in Body
Comprises big part of our body – 50 to 70% of body. 3 Liters of water in our blood. 14 liters of fluid between
the cells (the lymph to transport fats to blood system, GI tract, spinal column fluid, called extracellular fluid)
25 liters of Intracellular fluids = inside cells, muscle 73% water, fat cells 20% water
Solvent: metabolic processes, transport nutrients in blood, medium for enzyme reactions, blood volume
Body temp regulation: by sweating; water absorbs excess heat and secretes perspiration and cools our skin as
How does our body avoid excessive temperature? We are typically 98 degrees inside. We want to
dissapate heat on the inside. Blood flows to skin, capillaries open up, basal dilation occurs. When blood
flows to skin, heat can be exchanged thru skin and water can be lost from cooling. Cold – capillaries
constrict= basoconstriction – to conserve heat
Removal of body waste – urine and feces
Lubricates and cushions joints – biggest = spinal column; disks w/fluids in them and shock absorber
Amniotic fluid – cushioning protection, bathes developing fetus. It’s a shock absorber and also allows for
nutrient and waste exchange; they can taste the tastes and flavoring from mother’s amniotic fluid
Digestive secretions – everything we secrete in GI tract (HCl, Bicarbonate, enzymes in a solution)
Do we drink enough water?
Input: Drink 1000 ml (4 cups of water), water content of food 1000 ml, water from metabolism 350 ml
(1.5 cups) – from burning carbohydrates. In general we intake about 10 cups of water a day.
Output: 2 cups perspiration, 1.7 cups from respiration, 5.5 cups of urine, 0.6 cups in feces = 10 cups
output. A normal person would be in water balance if they drink about four cups of water.
“glacier water,” “mountain water” are words – no standards of identity, meaning nothing. Has no
meaning. Some bottled water comes from municipal sources (ie tap)
Most bottles use ozone to purify water, since Cl can leave residue taste and odor.
Sources of drinking water
Some bottled water comes from surface water. Ground water is from aquifers.
If it comes from
= a well that taps a confined aquifer – bubbles up from deep in the ground
that is supposed to be clean w/o too many dissolved minerals.
contains minerals inside the water, defined as containing 250 ppm dissolved minerals and
originated from protected underground source
Spring water comes from underground formation from which water naturally flows to the surface
Fluoridated water contains added fluoride, must be noted on the label. Bottled water does not contain
How we Maintain Water Balance
How do we regulate Water Balance?