Nutrition Mt 2 Water And Electrolytes:

Front 1

Our need for water

Back 1

our need for water is greater than our need for any other nutrient or mineral

we can survive any other deficiency for months or years

you can only survive a few days without water

<1 day without water alters the body's chemistry and metabolism

Front 2

Functions of water in the body:

Back 2

1. delivers nutrients
2. removes wastes
3. universal solvent (dissolves amino acids, glucose, minerals, etc. for transport)
4. Cleansing agent: nitrogen levels would build up to toxic levels
5. Lubricant (joints, GI tract, respiratory tract, mucus membranes)
6. Shock absorber: spinal cord, fetus
7. Pressure maintenance: keeps optimal pressure on the retina and lens
8. thermoregulation (evaporate heat loss)

Front 3

Water Loss

Back 3

1. Exhaled
2. Sweating
3. Urine/feces

Front 4

Symptoms of dehydration:

Back 4

1. thirst
2. weakness
3. exhaustion and delirium
4. death

Front 5

Symptoms of water intoxication:

Back 5

1. headache
2. muscular weakness
3. lack of concentration
4. poor memory
5. loss of appetite

Front 6

Quenching Thirst and Balancing Losses

Back 6

When the blood is too concentrated (having lost water but not salt and other dissolved substances), the molecules and particles in the blood attract water out of the salivary glands, and the mouth becomes dry. The hypothalamus plays the major role in monitoring the concentraiton of the blood. When the blood is too concentrated, or w=hen the blood volume or pressure s too low, the hypothalamus initiates nerves impulses to the brain that register as "thirst". The hypothalamus also signals the pituitary gland to release a hormone that directs the kidneys to shift water back into the bloodstream from the pool destined for excretion. The kidneys themselves respond to the sodium concentration in the blood passing through them and secrete regulatory substances of their own. The net result is that the more water the body needs, the less it excretes.

*Thirst lags behind a lack of water

Front 7

Daily Water Requirements:

Back 7

individuals will vary, therefore hydration can be maintained over a wide range of intakes.

DRI:
men ~ 3.7 liters from beverages and drinking water
women ~ 2.7 liters from beverages and drinking water
-remaining water need is met from foods
-body produces water in the breakdown of energy-yielding nutrients

Front 8

Diuretics:

Back 8

promote the excretion of water
1. Caffeine
2. Alcohol

Front 9

Hard water vs soft water

Back 9

Hard Water: water with high calcium and magnesium concentrations

Soft Water: water with high sodium concentration

*there is some evidence that soft water may aggravate hypertension and heart disease (condition that, due to its high calcium concentration, hard water may oppose).

Front 10

Cadmium contaminants in water:

Back 10

-displaces zinc from certain enzymes
-disturbs iron and copper transfer during pregnancy
-may promote: bone fractures, kidney problems, hypertension

Front 11

Lead contaminants in water:

Back 11

-absorbed more easily from soft water than from hard water (calcium in hard water may protect against lead absorption)
-old plumbing can contain cadmium or lead... (run cold water for 1 minute in the morning or whenever faucet hasn't been used for 6 hours)

Front 12

Other contaminants in public drinking water:

Back 12

bacteria, viruses, fuel runoff, industrial waste, agricultural waste

*public water systems remove some hazards
-disinfectant added (usually chlorine) kills most microorganisms

Front 13

Emergency or short term water disinfection:

Back 13

1. Boiling: bring to a rolling boil for 1 min.. let cool. kills all known pathogens

2. chlorine bleach: add 2 drops per liter of water. mix. let it stand for 30 min. usually effective against most pathogens

3. Disinfection tablets: use as directed. usually effective against moth pathogens if directions are properly followed

Front 14

Is chlorinated water safe?

Back 14

-consuming large doses of chlorinated tap water a day are related to an increased risk of colon, brain, and other cancers.

HOWEVER: in areas of the world without chlorination: 25,000 die every day from microorganisms that easily could have been killed w/ chlorine

Front 15

Bottled water vs. tap water?

Back 15

bottled water is not safer than tap water.

most water bottling companies disinfect with ozone rather than chlorine.

Front 16

Fluid regulation: osmosis:

Back 16

water diffuses down its concentration gradient.. when dissolved particles are separated by a membrane, water will flow to the side of greater solute concentration.

Front 17

How do the kidneys and the lungs participate in maintaining pH?

Back 17

Kidneys: they can excrete more or less H+

Lungs: excreting more or less CO2 (dissolves in blood to carbonic acid)