ESS 3 Lecture Notes - Lecture 10: Soy Protein, Action Potential, Caffeine
Water
Essential nutrient central to all body functions
➔Functions:
◆Regulates body temperature
◆Transports nutrients and oxygens
◆Participates in chemical reactions
◆Removes waste
◆Cushions tissues
◆Present in mucus and saliva
◆Acts as a solvent
◆Lubricates joints
60-70% of body is made up of water
➔Adult male has more total body water than an adult female
➔Ratio of water in body’s organs:
◆Muscle: 75%
◆Heart and brain: 73%
◆Adipose tissue: 15%
◆bone : 10%
Water moves in and out of cells through osmosis to maintain fluid balance in the body
➔⅔ of water is intracellular
➔⅓ of water of extracellular
Water intake
➔Thirst and satiety
◆Mouth, hypothalamus, and nerves sense changes
➔Thirst response lags behind the body's need for water
➔Water intoxication: caused by drinking 10-20 liters within a few hours
◆Symptoms: confusion, convulsions, death
◆Dilutes electrolytes
Water sources
➔Water provides about ⅓ of total water intake
➔Beverages
➔Foods
➔Metabolic water
◆Condensation reactions
◆Oxidation of energy-yielding nutrients
Water losses
➔Obligatory water excretion each day as urine
➔Vapor from lungs
➔Sweat from skin
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➔Loss in feces
➔Daily losses = 2500mL
Maintaining fluid balance
➔Within the hypothalamus is a collection of cells known as the thirst mechanism
◆Thirst mechanism: prompts us to feel thirsty when it detects:
● Increased sodium concentration in the blood
● Decreased blood volume and blood pressure
Minerals
Categorized by the amount required in the diet
➔Major minerals > 100mg/day
◆Sodium, potassium, chloride, calcium, magnesium, phosphorus, sulfur
➔Trace minerals < 100mg/day
◆Iron, zinc, copper, iodine, selenium, fluoride, chromium, manganese
Compose 4% of body weight
➔Mainly calcium → phosphorus → sulfur → potassium
Electrolyte balance
➔Electrolytes: electrically charged minerals
◆Attract water
● Balance = homeostasis
➔Predominantly outside of cell
◆Sodium, chloride, calcium
➔Predominantly inside of cell
◆Potassium, magnesium, phosphate, sulfate
➔Illness causes body to lose water → dehydration → alter fluid balance of body → alter
electrolyte concentrations
➔With help of the kidneys, electrolytes balance the fluid outside of cells with the fluid
inside of the cells
Sodium is the primary electrolyte in extracellular fluid
➔Functions:
◆Regulating fluid balance
◆Regulating blood pressure
◆Transmitting nerve impulses
◆Contracting muscles
◆Helping nutrient transport
➔Diets rarely lack sodium due to processed foods
◆Average intake in US exceeds the UL is 2300mg/day
●Average is 3400mg/day
◆Adequate is 1500mg/day (a little more than ½ a teaspoon)
◆Most Americans consume 3-4 times the recommendation
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Document Summary
60-70% of body is made up of water. Adult male has more total body water than an adult female. Water moves in and out of cells through osmosis to maintain fluid balance in the body. Thirst response lags behind the body"s need for water. Water intoxication: caused by drinking 10-20 liters within a few hours. Water provides about of total water intake. Obligatory water excretion each day as urine. Within the hypothalamus is a collection of cells known as the thirst mechanism. Thirst mechanism: prompts us to feel thirsty when it detects: Categorized by the amount required in the diet. Sodium, potassium, chloride, calcium, magnesium, phosphorus, sulfur. Iron, zinc, copper, iodine, selenium, fluoride, chromium, manganese. Illness causes body to lose water dehydration alter fluid balance of body alter electrolyte concentrations. With help of the kidneys, electrolytes balance the fluid outside of cells with the fluid inside of the cells. Sodium is the primary electrolyte in extracellular fluid.
