Module 8: Water and Electrolytes Flashcards
what allows water to attract other water molecules
- hydrogen side is +
- oxygen side is -
what are the two major compartments where water in found within the body
- intracellular
- extracellular
what percent of your body’s water is intracellular
60%
what percent of your body’s water is extracellular
40%
what is included in extracellular fluid
- interstitial fluid
- intravascular fluid
what is included in water intake
- beverages
- food
- metabolic water from breakdown of carbs, fats, and proteins
how much water is created from metabolism of carbohydrates, fats, and proteins
1 to 1.5 cups per day
what is included in water loss
- urine
- feces
- insensible losses: sweating, air expiration
why are water fluctuations in the body normal
body has no water storage mechanism
is was essential or nonessential
- essential
- required every day
what is the critical function of water in the body
- temperature regulation
- absorbing body heat and releasing heat via sweat
what controls the body’s perceived need for water (thirst)
hypothalamus
when is thirst triggered
- water levels are low in blood
- solute concentration is high in blood
does thirst occur at the same time that the body needs water
- no
- thirst lags behind the body’s need for water
what are the 2 hormones that help maintain hydration
- antidiuretic hormones
- aldosterone
describe antidiuretic hormone
released by pituitary gland to signal kidneys to retain water
describe aldoesterone
- produced by adrenal glands above kidneys
- induces kidneys to retain sodium and water
what is the recommended water intake for adults
1-1.5 mL/kcal of energy expenditure
define water intoxication
- dilution of blood electrolytes, particularly sodium
- aka hyponatremia
define hyponatremia
- low sodium levels in the blood
- caused by drinking excess water
how can dehydration occur
- excessive water loss via sweat
- vomiting and diarrhea
explain what happens to the body during mild dehydration
- thirst
- lack of mental clarity
- fatigue
explain what happens to the body during moderate dehydration
- symptoms from mild dehydration
- reduced athletic ability
explain what happens to the body during severe dehydration
- symptoms from moderate dehydration
- cramping
- heat exhaustion
- hallucinations
- heatstroke
what is urine the primary path for
- water loss and excretion of metabolic waste
- regulation of extracellular fluid composition
which organ controls urine and blood composition
kidneys
describe a nephron
- microscopic structures in the kidneys that filter blood
- 1 million in each kidney
what is the composition of urine
- water
- electrolytes
- urea
- creatinine
define electrolytes
minerals that become charged particles when placed in water
define cations and anions
- cations: minerals with positive charge
- anions: minerals with negative charge
what are 3 electrolytes important for water balance
- sodium
- potassium
- chloride
which electrolytes are primarily in extracellular fluid
- sodium
- chloride
which electrolytes are primarily in intracellular fluid
potassium
what is the main dietary source of sodium
- processed foods
- sodium added to foods for taste and/or as a preservative
what does the label sodium free mean
contains less than 5mg of sodium per serving
what does the label reduced sodium mean
contains at least 25% less sodium than the original product
what does the label unsalted/no salt added mean
- no salt added to recipe
- does not mean that there is no sodium
what is the AI for sodium
about 1.5g
what is the UL for sodium
2.3g
what percent of sodium chloride (table salt) is chloride
60%
what is the AI for potassium
4.7g
do most americans eat more or less potassium than recommended
less
what are some sources of potassium
- fresh fruits and vegetables
- legumes
- milk
- meats
- whole grains
- salt substitutes (KCl)
what are the functions of electrolytes
- water and electrolyte balance
- acid-base balance (pH)
- nerve transmission
- gastric pH
what are the 2 processes where water and electrolytes are moved across cell membranes
- diffusion
- osmosis
define diffusion
movement of solute from area of greater concentration to area of lesser concentration
define osmosis
movement of water from area with fewer particles to area with more particles
what is the normal blood pH that water and electrolytes try to stay within
7.35-7.45
how do electrolytes assist in nerve transmission
- sodium and potassium have charges when dissolved in water
- these charges assist in the function of excitable cells in nerves (and muscle fibers)
- nerve signals are sent as sodium moves into the cell and potassium moves out
which electrolyte primarily assist with regulating gastric pH
chloride in hydrochloric acid in the stomach
how often do sodium deficiencies occur
rarely
how does being deficient in sodium cause shock-like symptoms
- sodium loss is accompanied by water loss
- this decreases blood volume causing a system-wide drop in blood pressure
what are the two components of blood pressure readings
- systolic
- diastolic
define systolic blood pressure
peak pressure generated when the heart contracts and forces blood to move
define diastolic blood pressure
lowest blood pressure reading during cardiac relaxation
what are normal blood pressures
- systolic: <120
- AND
- diastolic: <80
what are prehypertension blood pressures
- systolic: 120-129
- AND
- diastolic: <80
what are hypertension stage 1 blood pressures
- systolic: 130-139
- OR
- diastolic: 80-89
what are hypertension stage 2 blood pressures
- systolic: >140
- OR
- diastolic: >90
what are some outcomes of hypertension
- increased risk for coronary heart disease and stroke
- kidney damage
85% of hypertension cases are _____
- idiopathic
- due to unknown cause
define essential hy[pertension
high blood pressure due to unknown cause (idiopathic)
how can you treat most hypertension
- diet
- exercise
- medication
does high sodium intake increase or decrease risk for hypertension
increase
should people with hypertension increase or decrease their potassium intake
increase
how does potassium reduce hypertension
relaxes blood vessels, lowering BP
what are 2 other minerals that are recommended for people with hypertension
- calcium
- magnesium
what is the DASH diet
- dietary approaches to stop hypertension
- clinically supported to reduce hypertension
what are the recommendations of the DASH diet
- increase potassium through fruits and vegetables
- increase magnesium through whole grains
- increase calcium through low fat dairy
- lower saturated fat
what is one element seemingly missing from the DASH diet
no recommendations for decreasing sodium intake
