Module 8: Water and Electrolytes

Hydrogen side in water is

slightly positive

Oxygen side in water is

slightly negative

Intracellular water makes up what percentage of water within the body?

60%

Extracellular water makes up what percentage of water within the body?

40%

What 2 things are part of extracellular water?

interstitial fluid and intravascular fluid

How do we get metabolic water?

from breakdown of carbs, fats, and proteins.
it is about 1-1 1/2 cups per day

3 ways we lose water

urine, feces, and insensible losses

does the body have a water storage mechanism?

no

what is the main function of water in the body?

body temp regulation

how does water regulate body temp?

water absorbs body heat, and heat is released at skin via sweat

What controls the body's need for water?

hypothalamus

when is thirst triggered?

water levels in blood decreased and solute concentration increases
perception of thirst lags behind time when body first needs water

what are the two hormones that help maintain hydration?

antidiuretic hormone and aldosterone

antidiuretic hormone

released by pituitary gland to signal kidneys to retain water

aldosterone

produced by adrenal glands above kidneys
induces kidneys to retain sodium and water

What is the water intake recommendation for adults?

1-1.5mL/kcal of energy expenditure

what happens you consume too much water, or water intoxication?

dilution of blood electrolytes, particularly sodium, also known as hyponatremia

what happens during mild dehydration?

thirst, some lack of mental clarity, and mild fatigue

what happens during moderate dehydration?

reduced athletic ability

what happens during severe dehydration?

cramping and heat exhaustion

what is a nephron?

microscopic structures that filter blood
1 million in each kidney

composition of urine

water, electrolytes, urea, creatinine

what are cations?

minerals with a positive charge

what is an anion?

minerals with a negative charge

sodium

primary cation in extracellular fluid

potassium

primary intracellular cation

chloride

an anion, more concentrated in extracellular fluid

Where do we get the majority of our salt intake?

in our processed foods. It is added to foods for taste and as a preservative

What is the adequate intake for sodium?

1500 mg per day for adults up to the age of 50
1200 mg per day for those over age 70

What is the upper limit for sodium?

2300 mg/day

What is the adequate intake for potassium?

4700 mg/day

What is diffusion?

movement from area of greater concentration to area of lesser concentration

what is osmosis?

movement of water across membrane from area with fewer particles to an area with more particles

nerve transmission

sodium and potassium have charges when dissolved in water
assist in function of excitable cells in nerves
sodium moves into the cell and potassium moves out

what happens when there is a sodium deficiency?

shock-like symptoms
blood volume decreases and veins collapse

systolic blood pressure

peak pressure generated when the heart contracts and forces blood to move

diastolic blood pressure

lowest blood pressure reading during cardiac relaxation

What can happen when someone has high blood pressure

increased risk for coronary heart disease and stroke
may also lead to kidney damage

essential hypertension

high blood pressure due to unknown cause

how is hypertension treated?

most is treatable with diet and exercise and medication

sodium's effect on blood pressure

high amounts may increase risk for hypertension

potassium's effect on blood pressure

appears to relax blood vessels, which decreases blood pressure

do we ever stop sweating?

no we sweat about 400-800mL per day

How long can we go without water?

we can not go over a week without drinking water

How much contractile ability is lost when you are dehydrated?

15-20%

What is sodium free?

must contain less than 5 mg of sodium per serving

What is considered low sodium

must contain less than or equal too 140 mg sodium per serving

What is considered reduced sodium?

At least 25% less sodium than the original product

What is considered unsalted or no salt added?

No salt added to the recipe

What is in salt substitutes?

potassium chloride

What is normal blood pressure

less than 120/80

What is prehypertension?

120-129/<80

What is hypertension stage 1

130-139/80-89

What is hypertension stage 2?

140 or higher/90 or higher

increased fruits and vegetable leads to what?

increased potassium intake

Increased whole grain lead to what?

increases magnesium intake

Low fat dairy leads to what?

increases calcium intake

What is another way to stop hypertension?

Lower saturated fat

What diet is the most common way to reduce hypertension?

DASH diet