Nutrition Mod 4.3: Water

Which are the two hormones that are responsible for conserving fluids and preventing dehydration when adequate fluids are not consumed?

1. Antidiuretic hormone (ADH) 2. Aldosterone

Describe the process of pespiration

1. physical activity in hot or humid weather increases body temp 2. sweat secreted to prevent body overheating 3a. Sweat requires energy which in turns expends heat from the body 3b. Sweat evaporating regulates and cools our body temperature

How many cups of urine do the kidneys filter and excrete per day?

4 cups

How long can a human survive without water?

A few days

Where is antidiuretic hormone (ADH) released from and what does it do?

ADH is released from the pituitary gland and signals the kidneys to conserve water

Explain how the concentration of ions inside and outside the cells dictate where water moves?

Blood volume increases -> water shift outside cell to bloodstream Blood volume decreases -> water shifts into cells

What are the water-soluble ions of the body?

Calcium, chloride, magnesium, phosphate, potassium and sodium

how can you tell from urine if adequate fluid intake is being maintained?

Clear or pale yellow = adequate fluid intake Dark yellow = inadequate fluid intake

when might the thirst mechanism be inadequate in recognizing your body's needs to increase fluid intake before dehydration occurs?

During athletic activities, fevers, in infants, children and the elderly

How does the water content of lean tissues and fat compare?

Fat tissue - 20% water content Lean tissue - higher water content More lean tissue = more water content

What is thirst?

Feeling, sense or need to drink generated by the body to ensure adequate fluid intake

Where is water found in the body?

Intracellularly within cells and extracellularly within the blood

Why does intake of proteins influence our production of urine?

Nitrogen metabolized from the amino acid must be excreted into urine as urea. More urea -> urine output

What is water toxicity and what are the symptoms?

Over consumption -> dilution of blood electrolytes and overwhelm the kidney's ability to secrete fluids -> extreme cases, death

Why is tap water and bottle water comparable in terms of drinking safety?

The Environmental Protection Agency (EPA), under the Safe Water Drinking Act, has set standards and contamination monitoring for all public water supplies and protocols to warn the public on safety concerns and steps to ensure safe drinking water.

what happens if the amount of urine excreted falls below two cups per day?

Urine becomes very concentrated and risks of kidney stones increases

What is the general recommendation for total fluids for women and men, and how much of that should be from fluids alone?

Women: 11/9 men: 15/13

What is a solvent?

a substance capable of dissolving other substances

What are the consequences of ignoring the symptoms of thirst?

endurance decline, fatigue and muscle cramps that could lead to coma or death

What symptoms may occur due to inadequate fluid intake and overheating?

heat cramps, heat stroke and heat exhaustion

Why isn't alcohol a suitable drink to replenish water in the body?

inhibits ADH -> dehydration

What ions do intracellular and extracellular water depend on respectively?

intracellular water volume: phosphate and potassium concentration extracellular water: chloride and sodium concentrations

What are electrolytes?

ion which minerals containing an electrical charge

What is the body's mechanisms to prevent overheating?

perspiration

Aside form water content control, what are the additional functions that water is needed for?

regulating body temperature, making saliva, bile, amniotic fluid, lubricating parts and removal of waster products

Why does intakes of sodium influence our production of urine?

sodium -> excess salt consumption -> blood sodium levels increase -> kidney filter our sodium into urine to maintain homeostasis -> water follows sodium -> more sodium in urine -> more water in urine - increased urine output

What is osmosis?

the process of water moving from a less concentrated area to a more concentrated area

how does fluid, proteins and sodium effect urine output?

when fluid, proteins and sodium are restricted, urine output declines

What is the total fluid volume of water in the body and how much volume of the body does it make up?

~ 10 gallons and 50-70%