Chapter 14: water and major minerals Flashcards
hypotonic
low ion concentration, which results in swelling and subsequent rupture
isotonic
concentraiton of ions outside the cell eqaul to that inside the cell
hypertonic
high ion concentration, causes shrinkage of the cell
source of water gain for the body
- fluids
- water content in food
- water produced from metabolism
sources of water loss for the body
- skin perspiration
- lung respiration
- feces
- sensible losses (urine)
what releases ADH
posterior pituitary
what causes the release of ADH (vasopressin) and how it helps the body to conserve water
the hypothalamus receives signals if increased blood osmolarity from various receptors, stimulates the posterior pituitary
dehydration can be caused by
- medical conditions where water is lost
- heavy exercise
- hot weather, dry environments, high altitudes
major minerals
- need 100 mg or more daily
- found in larger quantities in the body
trace minerals
needed/stored in smaller amounts
processed foods are the largest dietary source of ___ for most people
sodium
key functions of sodium in the body
- required for normal nerve and muscle function
- helps absorb glucose and some amino aicds in small intestine
- aids in water balance and maintains blood pressure
sodium deficiency
- extremely rare as dietary deficiency
- vomitin and dirrhea, especially in infants can cause sodium depletion
- more commom cause of hyponatremia is excess water consumption
excess sodium and upper level
- excess sodium generally gets excreted by the kidneys without serious acute effects
- greater than 2g/day leads to more calcium being excreted in urine, so far has not been linked to osteoporosis
major functions of potassium
reduces calcium secretion
may blunt the effects of high salt intake and help keep blood pressure normal
* suppresses renin-angiotensin system
* promotes secretion of sodium and water
hypokalemia
- can be immediately life-threatening due to arrythmia
- may occur with diuretic drugs or eating disorders
hyperkalemia
- can also cause fatal arrhythmia
- not observed due to high dietary intake
- kidney disease, supplement overdose, potassium-sparing diuretics
chloride function
helps maintain membrane potentials
almost all comes from table salt
where is most chloride found
extracellular fluid
major functions of calcium
- development and maintenence of bones and teeth
- blood clotting
- transmission of nerve impulses
- muscle contraction
- cell metabolism
parathyroid hormone increases
- absorption from gut
- reabsorption from kidney
- resorption from bone
phosphorus absorption is enhaned by
vitamin D
most of the body’s phosphorus supply is in
bone (hydroxyapatite)
phosphate functions
phosphates are the main intracellular anion
phosphate is a component of
- ATP creatine phosphate
- DNA and RNA
- phospholipids
- other enzymes and cellular messengers
- regulation in acid-base balance
key functions of magnesium
- stabilizes ATP
- contributes to bone strucutre and mineralization
- membrane protential
- adequate intake may reduce risk of meatbolic syndrome, hypertension, cardiovascular disease
sulfur is required for
- stabilization of protein structures
- detoxification (glutathione)
