Chapter 10 Water 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.

Water 1. 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?

Copyright 2010, John Wiley & Sons, Inc. The tissue with the lowest water content is blood bone fat muscle

Copyright 2010, John Wiley & Sons, Inc. 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 _______ Copyright 2010, John Wiley & Sons, Inc.

Hydrolysis and Condensation Reactions Copyright 2010, John Wiley & Sons, Inc.

Water (functions) Water helps control the PH Copyright 2010, John Wiley & Sons, Inc.

The normal body pH of 7.4 is slightly basic slightly acidic very basic very acidic

Copyright 2010, John Wiley & Sons, Inc. Water and pH Balance

Copyright 2010, John Wiley & Sons, Inc.

Osmosis Copyright 2010, John Wiley & Sons, Inc.

Need for Water in the Body Compared to Intake Extra credit: collect your urine x 1 day.

Copyright 2010, John Wiley & Sons, Inc. Consequences of Dehydration

Copyright 2010, John Wiley & Sons, Inc. Resources for Water in the Diet

Copyright 2010, John Wiley & Sons, Inc. Thirst Mechanism

Copyright 2010, John Wiley & Sons, Inc. 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.

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.

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. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein..