water and electrolytes

water chem structure

2 hydrogen 1 oxygen

water bonding (5)

- causes shift in charge among atoms
- H side slightly positive
- O side slightly negative
- allows water to attract other water
- charged substances can dissolve in it

water 2 major body compartments (2)

- intracellular
- extracellular

intracellular water

about 60% of body water

extracellular water (3)

- 40% of body h2o
- includes interstitial fluid
- and intravascular fluid

metabolic water (3)

- water intake
- from breakdown of carbs fats, proteins
- 1 to 1.5 cups/day

insensible water losses (2)

- sweating
- air expiration

body and water storage (3)

- has no h2o storage mechanism
- losses must b replaced w consumption
- essential, every day

critical function of h2o in body (3)

- body temp regulation
- absorbs body heat
- heat released via sweat

hypothalamus

controls body's perceived need for h2o

thirst trigger (3)

- blood water levels drop
- solute concentration goes up
- thirst perception lags behind when body 1st needs h2o

hydration maintenance hormones (2)

- antidiuretic hormone
- aldosterone

antidiuretic hormone

released by pituitary gland 2 signal kidneys 2 retain h2o

aldosterone

- produced by adrenal glands (above kidneys)

water intake adult rec

- 1-1.5 mL/kcal of ATP expenditure
- food/bev combined
- vary via disease, activity

water intoxication (hyponatremia) (3)

- excess h2o consumption
- dilution of blood electrolytes
- particularly Na

dehydration

- body's function altered @ all levels
- mild, moderate, severe

urine (3)

- primary path for
- water loss, metabolic waste excretion
- extracellular fluid composition regulation

kidneys (2)

- controls urine and blood composition
- nephrons

nephron (2)

- microscopic blood filtering structure
- 1 million in ea kidney

urine composition (2)

- water, electrolytes
- urea and creatinine

electrolytes

minerals placed in h2o become charged particles

cations

minerals w positive charge

anions

minerals w negative charge

Na+, K+, Cl-

important electrolytes for water balance

sodium Na+

primary cation in extracellular fluid

potassium K+

primary intracellular cation

chloride Cl-

anion more concentrated in extracellular fluid

dietary sodium

health professionals universally advise moderating salt intake

main dietary source of Na (3)

- processed foods (77%)
- taste additive/preservative (5-12%)
- very little naturally occurring

sodium free claim

must contain

dietary chloride (2)

- natural content of most foods is low
- table salt = 60% Cl

adequate intake (AI) for Na

- 1500 mg/day adults up to 50
- 1200 mg/day over 70

upper limit (UL) for Na

2300 mg for adults

dietary potassium adequate intake (AI)

4700 mg/day
- most Americans eat less than the AI

potassium rich sources (5)

- fresh fruits/veg
- legumes
- milk
- wheats/whole grains
- salt subs

water/electrolyte balance

moved across cell walls via diffusion/osmosis

diffusion

movement from greater concentration to lesser

osmosis

movement of h2o across membrane from area w fewer particles to area w more

acid-base balance (pH)

maintenance of normal blood pH

nerve transmission (electrolyte function) (3)

- Na and K, charge when dissolved in h2o
- function of excitable cells in nerves
- Na moves in, K moves out

gastric pH (3)

- HCl contains chloride
- protein digestion
- mineral absorption

sodium deficiencies (3)

- rarely occur
- Na loss accompanied by body h2o loss
- blood volume lowers and veins collapse

Na deficiency symptoms

shock-like

water intoxication and sodium deficiency

intoxication can result in a condition associated with low blood sodium

blood pressure readings

- 2 components
- systolic
- diastolic

systolic blood pressure

peak pressure generated when heart contracts, forcing blood to move

diastolic blood pressure

lowest reading during cardiac relaxation

hypertension (2)

- elevated BP
- stage 1, stage 2, hypertensive crisis

hypertension prevalence

- 25% of americans based on previous definition
- 54% have high bp under 2017/18 definition

hypertension results

greater risk for coronary heart disease, stroke, kidney damage

hypertension causes

- 85% cases have unknown cause
- known as essential hypertension

hypertension treatment

diet, exercise, medication

sodium and blood pressure (2)

- high amounts may increase hypertension risk
- required on food labels

potassium and blood pressure (3)

- appears 2 relax blood vessels
- lowers BP
- rec to increase intake

minerals that may help BP (3)

- Mg
- Ca
- K

potassium and nutrition facts

not on original label, but on the new label

DASH eating plan (4) (dietary approaches to stop hypertension)

- increase fruits/veg --> K
- increase whole grains --> Mg
- low fat dairy --> Ca
- lower sat fat