Nutrition 251 Hybrid Final Exam Study Guide Questions on Exam 50 on new content 15 on cumulative material Week 14 Lesson 10 Water and Major Minerals Water 1 List the components of water intake for a typical adult In liters day and in ml kcal what is the typical water recommendation for college students who are not in sports Approximately what percent of this water typically comes from foods eaten each day Water intake recommendations depend on body size activity environmental temperature and humidity Typical recommendations 1 0 to 1 5 ml kcal Typical of college students expend 2000kcals per day consume 2 3 liters of water per day 2000kcals x 1ml 2 liters 2000kcal x 1 5ml 3 liters therefore recommended range is 2 3 liters About 700 1000ml comes from food 2 What is the consequence of a loss of about 3 4 of your body weight by water loss sweating breathing etc If 3 4 is lost from water physical performance is impaired flushed skin and apathy can occur Ex this is why construction workers in hot climates and athletes during games should always have access to water to perform as well as they can and keep from dehydration 3 For a typical adult who consumed no food or water for a day what is the estimated obligatory water loss List the components of water lost by a typical adult who is eating and drinking What are the 2 largest components of water loss To keep water balance obligatory water loss occurs through urine daily The minimum amount in adults is about 500 ml 2 cups everday Water is also lost from skin as sweat The average loss is about 2500 ml for those who eat and drink normally 4 Why are some elders at risk for dehydration With age total body water decreases This means elders have less reserve of water compared to younger people Many elders no longer have sensitivity to thirst as when they were young Mid fever or during a hot humid summer can cause elders to critically lose body water Some adults may voluntarily reduce fluid intake due to problems with frequent urination Those living with or caring for elders should remind them to drink throughout the day especially during warmer weather A good general guideline is for elders to try to drink at least 6 glasses of water or other beverage each day 5 At what level would water be toxic to humans What are the consequences of consuming too much water Consuming 10 or more liters of water in a few hours can cause water toxication very rare Symptoms confusion convulsions possible death due to hyponatermia 6 Define extracellular water and intracellular water Where is interstitial fluid Name the major electrolytes in the extracellular and intracellular compartments of the body Describe the basic principle of osmosis which explains why fluids are maintained in these compartments See text pg 374 375 Intracellular water liquid inside cells Major electrolytes potassium cations and phosphate anions Extracellular water liquid outside cells Major electrolytes sodium cations and chloride anions Interstitial fluid is found outside surrounding cells in tissue spaces Osmosis water can pass through semipermeable membrane to where a solvent concentration is higher is order to equalize both sides of this membrane 7 Describe the basic regulation of body water at the level of the nephron What is the function of the glomerulus which is surrounded by a capsule What happens in the tubules of nephrons What is meant by re absorption Your kidney filters 180 liters of water each day Where does it all go How much is excreted as urine by the average adult Basics of Nephron for regulating body water 1 FILTRATION blood flows through capillaries and is filtered by the glomerulus Electotrolytes water and urea are filterd into tubules of nephron In adults about 180 liters of water are filtered daily 2 REABSORPTION water and electrolytes and reabsorbed back into blood as needed due to osmosis and membrane pumps About 99 of water is reabsorbed Hormones regulate membrane pumps that are capable of electrolyte water reabsorption EXCRETION excess water urea and electrolytes travel through nephron tubules to bladder to be excreted via urine 3 The glomerulus filters blood from capillaries into the nephron tubule In the tubules of nephrons electrolytes water and urea are filtered to the bladder Since kidneys filter 180 liters of water a day 99 is reabsorbed and the excess is excreted as urine 8 The consumption of alcohol inhibits ADH What is the consequence in the kidney of inhibiting ADH Therefore would you recommend that you drink water or not drink water before going to bed after a night of responsible drinking of alcoholic beverages i e to prevent a hangover the next day Describe the role of ADH in the regulation of water balance When the kidney inhibits AHD to reabsorb more water from nephron tubules back into the blood which dilutes blood sodium concentration Therefore it is recommended to drink water before going to bed after drinking alcohol to prevent a hangover ADH is released to lower sodium levels in blood when there is a drop in blood volume This keeps the right amount of liquids levels in blood so blood pressure does not increase dramatically 9 If you are very thirsty what hormone is elevated that regulates water balance Explain the hormonal regulatory process when blood sodium level is low ie could also result in low blood pressure What happens to sodium and water in the kidney tubules during this process When you are thirsty dehydrated blood flow is low resulting in lower blood pressure To regulate this the body releases renin into blood to activate the protein angiotensinogen and convert it to angiotensin Angiotensin causes release of the hormone aldosterone this causes the kidney to reabsorb sodium and other electrolytes to attract water Sodium is reabsorbed into blood which causes water to follow it bc of osmosis and brings blood pressure back up to normal 10 Explain why ORT has saved the lives of millions of children in third world nations What is the role of sugar ie glucose in this therapy ORT oral rehydration therapy Electrolyte imbalances can occur when too much Na Cl and K are lost through excessive vomiting diarrhea and or sweating In developing nations where sanitation may be poor diarrhea can be a major cause of death for children especially young children Children actually die of dehydration because water absorption in the digestive tract is often shut down by the bacterial infection A simple solution of 1 cup of boiled water a pinch of salt NaCl