 Welcome back, we all these classes we have seen the importance of all nutrients like carbohydrates, proteins, fats, minerals and vitamins. Now, the next important nutrient in the body is water, so it comprises 50 to 70 percent of the total body weight and muscles also contain a lot of water about 73 percent and fat contains 20 percent in the body not outside and intracellular fluid is the fluid within the cells which comprises of two-thirds of the total body water and extracellular fluid is outside the cells that is like in blood and lymph it is composed of one-third of the total body water and this water is an essential nutrient without which death occurs and therefore we cannot live without food without vitamins and minerals and without water. All these are very important for life. Now, functions of water it is a universal solvent the water dissolves all the nutrients in it in and carries it to various cells through the blood and it dissolves the waste products and helps to eliminate them from the body through the feces through perspiration through urine and other ways. Then urea if the urea remains in the body there is a chance of becoming uremic that means the blood is having urea and it becomes toxic therefore urea also is dissolved in water and it is eliminated from the body so that the body homeostasis is maintained and carbon dioxide which is a waste product of the metabolism is has to be eliminated therefore this carbon dioxide is dissolved in blood and eliminated through perspiration therefore when the carbon dioxide remains in the body the pH of the blood becomes more and more acidic and causes problem. Then they remove the waste products like sodium whenever there is excess of sodium there is the water removes them by getting the urination more number of times and the excess amount of urine is excreted then normally there is 1 to 1.5 liters per day of urine is excreted through which all the waste products are excreted from the body and the homeostasis is maintained then it avoids concentrated urine so the urine is always diluted and excreted so when you the urine is concentrated then there is a chance of getting the kidney stones in the kidneys therefore whenever water is dissolves all the waste material and excretes it there is no chance of having kidney stones and the kidneys are healthy. Now body temperature regulation also is carried out by water so all the metabolism in the body generates a lot of heat so the water that is present in the body it absorbs the excess heat and maintains the body temperature and it secretes fluid via perspiration so that and the skill is because of the perspiration skin becomes cool and as the perspiration evaporates the temperature is maintained and it is a lubricant for joints and synovial fluid the fluid that is present in the joints and it is a shock absorber see when the mother is pregnant there is amniotic fluid in the placenta so that because of this amniotic fluid the baby is not directly hurt so it protects the baby against any injuries then cerebrospinal fluid also helps us to protect our brain and spinal cord. Now there are daily water losses is through urine this is the excess I mean the largest amount of water loss is through urine then the second is the skin and lungs is through the water vapor when we exhale you feel the air that is warm with water vapor and some amount of water is lost through feces the sources of water when we say water it is not pure water which gives us fluid in the body so all the fluids like water and other beverages are supplying water to the body then the fresh fruits and vegetables meat and except all the dried grains and foods you have water in all the other foods and you get water from metabolism so whenever there is a metabolism of carbohydrate fats and proteins the end product is water and energy nutrients like carbon dioxide energy and water the factors affecting the water balance and its maintenance the ability of the body to adjust fluids and electrolytes and acid base balance these are influenced by age so as the age increases the ability to adjust fluids will decrease and when it is an infant stage then the body is very small and the amount of water is less so the excess urine is excreted the large amount of urine is excreted and the body has to maintain that is why the infant has the milk as the main diet where 90% of it is water then gender and body size and environmental temperature and lifestyle so infants immature kidneys are less able to conserve water then so they lose more fluids whereas in adults because of higher metabolic rate it increases the fluid loss and when it comes to elderly people the aging increases the risk of dehydration there is metabolism and loss of water is there therefore dehydration occurs and women have the proportionately more amount of body fat and less water compared to men environmental temperature there are fluid losses through sweating and the perspiration is increased in hot weather and the body attempts to dissipate heat whenever there is lot of perspiration the body temperature becomes cool and lifestyle and other factors like diet exercise stress affect the fluid electrolyte and acid balance for dehydration it is the deficit of total body water with whenever there is disruption in the metabolic process there is reduction in the body water which is called as dehydration so this is also a reason for hypernatremia hypernatremia is increased sodium content in the body so whenever there is increased sodium content it attracts water and try to excrete from the body therefore dehydration may occur and the term dehydration must be distinguished between hypovolemia that is hypovolemia is there is loss of the blood volume particularly the plasma so when there is loss of blood volume it does not refer to as dehydration but when the total body water reduces then we can call it as dehydration and most of the people can tolerate 3 to 4 percent decrease in the total body water without any difficulty so we can stay for certain time even though we are thirsty we can wait for some time then sometimes when it increases to 5 to 8 percent it causes fatigue and dizziness and over 10 percent it can cause physical and mental deterioration and accompanied by severe thirst and dehydration occurs when free water loss exceeds free water that is there is no balance intake and output and usually it happens when there is heavy exercise there is lot of dehydration and any disease condition when there is fever also there is lot of excess of heat along with water thereby there is dehydration and a decrease of more than 15 to 25 percent of water is fatal at this stage the person the death is sure then mild dehydration is characterized by thirst whenever the body reduces the water content the brain uses a signal to take water by creating thirst and general discomfort so this results when you take normal water through the mouth now excess of water also is dangerous some people keep on drinking water more and more water so it can get intoxicated so water intoxication is also known as water poisoning or dilution in hyponatremia so this is potentially dangerous and death can occur because the brain functions lose its normal balance and electrolytes are disturbed in the body and the since it is a hyponatremia the sodium quantity becomes very less in the body compared to the water content thereby it affects the brain and there is pushed outside safe limit of over hydration so you can see how the edema occurs this is a normal foot and when there is over hydration when here the person consumes more and more of fluids there is so much of edema although water is essential for life if a person drinks too much the blood becomes dangerously diluted by and the salts that are to be present in normal levels are decreased too much so according to the American scientist it is this condition is called as hyponatremia which leads to water intoxication so some of the symptoms are you get headache fatigue nausea vomiting frequent urination because the body has to lose the excess water so there is frequent urination and mental disorientation because the sodium level in the blood decreases so when a person drinks too much of water the kidneys are overloaded with work so they cannot flush it out as well and cause excess water to enter into the cells so this causes all these cells to swell and cause edema so similar thing happens to the brain cells and the when the brain cells start swelling and getting hydrated this condition is fatal and water just like any other substance can be considered as a poison water is an essential nutrient and it can also become a poison when it is over consumed over a specific period of time so more than 6 liters of water if it is consumed for a long period then the body starts getting water intoxicated so whenever the body gets water intoxicated the nutrients that are present in the blood and the other substances get diluted and the body gets disoriented so even healthy people can get water intoxication so this is the importance of water and how it is important to take sufficient amount of water what happens in dehydration and how important it is to maintain the fluid balance acid base balance and water balance and what happens if we take excess amount of water so that we feel if we take excess amount of water we are healthy but it gets intoxicated thank you.