NSC 170C1 1st Edition Lecture 18 Outline of Last Lecture I. MineralsOutline of Current Lecture II. Importance of WaterIII. Water balanceIV. Bottled vs. TapCurrent LectureV. Why is water so important? A. It is the most abundant substance in your bodyi. The average healthy adult is about 60 percent watera) Amount of body water depends on age, gender, and the amount of fat and muscle tissue you carryii. Muscle tissue is 65 percent water; fat tissue is only 10 to 40 percent wateriii. Men have a higher percentage of muscle mass and therefore more body water than womenB. Water is essential for maintaining fluid balancei. Electrolytes are minerals important in fluid balancea) Include sodium, potassium, phosphate, magnesium, calcium, and chlorideii. Attract water into and out of your cellsC. Water Is the Universal Solventi. A solvent is a liquid in which a substance dissolvesii. As a solvent, water is part of the medium in which molecules come into contact with each other, and allows chemical reactions to take placeD. Water Is a Transport Mediumi. Water is a major component of blood.ii. Water helps transport oxygen, nutrients, and other important substances to your cellsiii. Water transports waste products away from cells to be excreted inurine and stoola) Lymph fluid is almost entirely wateriv. Transports proteins back to the bloodstreama) Important in the absorption of fatsv. Transports wastes and microbes through lymph nodes, where defensive cells consume the harmful substancesE. Water Helps Maintain Body Temperaturei. Water in your circulating blood absorbs heat from your internal core and carries it to the skin for releaseii. During exercise, evaporation of sweat on your body releases heat to help cool you down and maintain a safe body temperatureiii. When you are cold, less blood flows to your body surface in order to keep your internal organs at your body core warmF. Water Is a Lubricant and a Protective Cushioni. Combined with other molecules, water acts as a lubricant for your jointsii. As a component of tears, it lubricates your eyes and flushes out dust and debrisiii. It is part of the saliva that moistens your mouth and foods and themucus that lubricates your intestinal tractiv. It is a central component of the fluid that surrounds your brain and protects it from injury during a fall or traumav. During pregnancy, the watery amniotic fluid protects the fetus from any physical harmVI. What Is Water Balance and How Do You Maintain It?A. You Take in Water through Beverages and FoodB. You Lose Water through Your Kidneys, Large Intestine, Lungs, and Skini. Losing Too Much Water Can Cause Dehydrationii. Other Ways to Tell if You Are Dehydratediii. Consuming Too Much Water Can Cause HyponatremiaC. Water balance: a state in which an equal amount of water is lost and replenished dailyi. Too much or too little water in your system can cause health problems.ii. Water is lost from the body in several ways, and several mechanisms help you to replenish those lossesiii. You Take in Water through Beverages and Foodiv. Most of your daily water comes from beverages such as water, milk, juices, and soft drinksv. You get some water from the foods you eat, though much less in comparisonvi. Even seemingly dry foods provide some watervii. A small amount of water is also generated during metabolismD. Water Intake and Water Outputi. You Lose Water through Your Kidneys, Large Intestine, Lungs, and Skinii. You lose water daily through four routes:a) Your kidneys in the form of urineb) Intestinal fluids in your stoolc) Water that evaporates when you exhaled) Your skin when you release the heat produced in your body coree) You Lose Water through Your Kidneys, Large Intestine, Lungs,and Skinf) Insensible water loss describes loss of water through evaporation of your breath and through your skin. Doesn’t include the water lost in sweatg) The amount of water lost in sweat varies depending on environmental factors (temperature, weather, clothing worn,and the amount of physical activity you are doing)III. DehydrationA. Dehydration is the state in which the body has too little waterB. It can result from:i. Not drinking enough fluidii. Water losses due to illness such as diarrhea, vomiting, or feveriii. Use of diuretics (such as alcohol and certain medications)C. If dehydration persists, it can cause weight loss, dizziness, confusion, inability to perform physical activity, and, in extreme cases, deathD. Your Thirst Mechanism Signals Dehydrationi. The thirst mechanism includes various bodily reactions caused by dehydration that signal you to drink fluidsii. Dry mouth is due to increased concentration of electrolytes in your blood, which limits the water available to make salivaiii. Increased concentration of electrolytes, especially sodium, in the blood is detected by the brain and triggers thirstiv. The brain also signals the kidneys to remove less water from the blood and concentrate urineE. Other Ways to Tell if You Are Dehydratedi. Elderly people, individuals who are physically active or have vigorous jobs, or people experiencing fever, diarrhea, and/or vomiting are at risk for dehydrationii. Measuring body weight before and after physical activity is one way to monitor hydration statusiii. Urine color can also be used to assess hydrationa) What the Color of Your Urine Can Revealb) If you collect your urine in a cup and it looks like the color of 1 through 3 on the chart, you are well hydratedc) If your urine resembles color 7 or is darker, you are dehydrated and need to drink more fluidsiv. If you are physically active and the color of your urine darkens duringthe day, you likely need to drink moreF. Consuming Too Much Water Can Cause Hyponatremiai. Overhydration can cause hyponatremia, a low level of sodium in the blood, which may result in dangerous swelling of the brainii. Symptoms of hyponatremia include fatigue, confusion, and disorientation, which may be mistaken for dehydrationiii. The seriousness of overhydration has prompted the USA Track & Field Association to revise its hydration guidelines for long-distance runners to avoid hyponatremiaIV. How Much Water Do You Need and What Are the Best Sources?A. Daily water requirement depends on physical activity, environmental factors, and dietB. Women: 12 cups of fluid daily (9 cups from beverages)C. Men: 16 cups of fluid daily (13 cups from beverages)D. Caffeinated coffee, tea, and soft drinks do contribute to daily water needs.i. 20 percent of