chapter 10 water and the electrolytes. copyright 2010, john wiley & sons, inc. at what point do...
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Chapter 10Water and the Electrolytes
Copyright 2010, John Wiley & Sons, Inc.
At what point do you think dehydration can impair physical and cognitive performance?
a. 1-2 % body weight loss
b. 5-7 % body weight loss
c. 10 % body weight loss
d. 20 % body weight loss
Water
What are the functions of water in the body?
Copyright 2010, John Wiley & Sons, Inc.
Copyright 2010, John Wiley & Sons, Inc.
Water1. Solvent
2. Transport
3. Lubrication: Water functions as a lubricant and cleanser.
A. synovial fluid lubricates joints,
B. saliva assists in chewing, tasting and swallowing
4. Protection: Spinal fluid protects against shock.
5. Regulation body temperature: by holding onto heat and changing temperature slowly.
6. Cleanser: Tears wash away dirt
7. Chemical reactions
8. Acid Base Reactions
Water molecule
Copyright 2010, John Wiley & Sons, Inc.
Water is a polar solvent in the body.
The polarity of water comes from hydrogen and oxygen.
Copyright 2010, John Wiley & Sons, Inc.
Substances that separate into positively and negatively charged ions in water are
a) solvents
b) non-polar
c) electrolytes
d) inert
Sodium, chloride, and potassium
Copyright 2010, John Wiley & Sons, Inc.
Water is a good solvent because
a) it contains sodium and chloride ions.
b) it dissolves lipids.
c) it emulsifies protein.
d) it is polar.
Copyright 2010, John Wiley & Sons, Inc.
How is water distributed in the body?
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The tissue with the lowest water content is
blood
bone
fat
muscle
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Water found inside cells of the body is called
a) amniotic fluid
b) extracellular fluid
c) intracellular fluid
d) interstitial fluid
Copyright 2010, John Wiley & Sons, Inc.
Water in the Body About two-thirds of body water is found inside cells.
Water inside cells is called intracellular fluid. Intracellular fluid has the highest concentration of
protein, extracellular fluid has less, and interstitial fluid has the lowest concentration of protein.
Intracellular fluid has the lowest concentration of sodium and the highest concentration of potassium.
Extracellular fluid is found outside the cells. Extracellular fluid has the highest concentration of
sodium and chloride and a lower concentration of potassium.
Interstitial fluid consists of lymph, blood plasma and extracellular fluid.
Copyright 2010, John Wiley & Sons, Inc.
Water helps to regulate normal body temperature for which of the following reasons ?
water changes temperature slowly.
when body temperature rises, sweat is produced which evaporates to cool the body.
when body temperature falls, blood flow near the surface is restricted, conserving body heat.
when body temperature falls, blood flow near the surface is increased to warm up the body.
Water (functions)
Water helps drive reactions in the body
A reaction that breaks large molecules into smaller ones by the addition of water is called _______
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Hydrolysis and Condensation Reactions
Copyright 2010, John Wiley & Sons, Inc.
Copyright 2010, John Wiley & Sons, Inc.
Water (functions)
Water helps control the PH
Copyright 2010, John Wiley & Sons, Inc.
Copyright 2010, John Wiley & Sons, Inc.
The normal body pH of 7.4 is
slightly basic
slightly acidic
very basic
very acidic
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Water and pH Balance
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Osmosis
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Copyright 2010, John Wiley & Sons, Inc.
Need for Water in the Body Compared to Intake
Extra credit: collect your urine x 1 day.
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Consequences of Dehydration
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Resources for Water in the Diet
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Thirst Mechanism
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Antidiuretic Hormone Assists in Fluid Intake
ADH (anti diuretic hormone) signals the kidneys to reabsorb water back into the bloodstream
Copyright 2010, John Wiley & Sons, Inc.
Electrolytes: Sodium, Potassium and Chloride
The correct combination and amounts of electrolytes are essential for life.
Distribution of electrolytes affects the distribution of water throughout the body.
Sodium, potassium and chloride are the principle electrolytes in body fluids.
Copyright 2010, John Wiley & Sons, Inc.
Drinking plain water after a long period of excessive sweating can do all of the following except;
dilute the sodium in the blood.
cause water toxicity.
result in nausea, muscle cramps and confusion.
cause rebound dehydration.
P.S. Water absorption is affected by the volume of water consumed (increases absorption) and the nutrients/solutes it comes with (decreases absorption)
Overhydration
An excess of water can affect distribution among body compartments. This can happen during illness or prolonged exercise w/o replenishment of electrolytes, water intoxication leads to hyponatremia.
Early symptoms look similar to dehydration: nausea, muscle cramps, disorientation, confusion.
Copyright 2010, John Wiley & Sons, Inc.
Copyright 2010, John Wiley & Sons, Inc.
Most of the salt consumed by Americans is
a) found naturally in food.
b) added during home
preparation.
c) added at the table.
d) added to food during processing and manufacturing.
Blood Pressure and Electrolytes Sodium is linked to high blood pressure (this
is where the recommendation of less than 1500mg/day comes from)
Diets rich in calcium, magnesium, and potassium associated with low blood pressure.
What are some strategies to keep blood pressure low?
Copyright 2010, John Wiley & Sons, Inc.
Lifestyle choices for blood pressure Eat plenty of fruits/vegetables (high in
potassium and magnesium) Choose foods with less salt (non-processed) Aim for healthy weight – BP increases as
weight goes up Increase physical activity If you drink alcohol- excessive consumption
associated with high blood pressure. If you smoke-quit!
Copyright 2010, John Wiley & Sons, Inc.
Copyright 2010, John Wiley & Sons, Inc.
Summary of Water and the Electrolytes
Copyright 2010, John Wiley & Sons, Inc.
Fluid requirements for infants, are proportionately greater than those for adults because:
Infants have less surface area for evaporation
Infants are more active than adults
Infants weigh less than adults
Infants have immature kidneys that are not able to concentrate urine
Copyright 2010, John Wiley & Sons, Inc.
Chapter 10
Copyright 2010 John Wiley & Sons, Inc.
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