Lab 3 Flashcards
molarity / 1 molar
1 mole + however much solvent to create total of 1 L solution
molality / 1 molal
1 mole solute + 1 L solvent
why is molal more precise than molar?
molal tells you exact amount of solute and solvent, in molarity amount of solvent is unknown and dependent on volume of solute
1 mole meaning
1 mole = avogadros number of particles
dissolving glucose vs dissolving water
hydration sphere forms around glucose vs salt dissociates and hydration spheres form around the ions
osmolality
total molality of a solution - takes into account dissociation
- for glucose molality = Osm
- for NaCl molality * 2 = Osm
blood plasma osmolality
280-300 mOsm
- remember milli = 1000
3 isotonic solutions to increase blood volume / hydration
ringers lactate, normal saline, and 5% dextrose aka D5
tonicity
relative term comparing the concentration of solutions
isotonic
no net movement of water between solutions
why is isotonic solution needed for IV??
if not isotonic liquid would move in and out of cells causing swelling and lysing or crenation/shrinking
hypotonic
- if hypotonic to cell = net movement of water into cell
- osmotic pressure is less
ringer lactate and when given?
- K+, lactate, and Ca2+
- lactate provides a source of energy
- given during conditions that cause hypoxia (low O2) such as sepsis and burns
normal saline and how much salt
- 0.9% saline solution that is isotonic to blood plasma
D5
5% dextrose, isotonic to blood plasma, given when person cannot consume food by mouth
water intoxication
- excessive water consumption –> cells in brain cells –> coma and death
effect of hypotonicity on RBC
- water enters cell causing hemolysis and swelling
hypertonic effect on cell
- water leaves cell
- osmotic pressure is higher
effect of hypertonicity on RBC
- water leaves cell causign shrinking and crenation
regulation of blood osmolality (entire flow)
dehydration –> lowered blood volume, osmolality, and pressure –> detection by osmoreceptors in hypothalamus –> stimulation of thirst center of hypothalamus & ADH secreted by posterior pituitary –> increased reabsorption in kidneys –> blood volume increases
which of the 3 test tubes was clear vs cloudy and why?
- cells cause reflection of light and make it cloudy
- hypotonic = clear because of lysis of cells
- isotonic = cloudy because of cells
- hypertonic = moderately cloudy since cells are shrunken
albumin
protein in blood vessel, increases osmotic pressure and keeps water in blood vessels, without it edema would occur as water goes into interstitial fluid
osmotic pressure
ability of something to pull water
percentage meaning
grams of substance / 100mL of liquid
ADH and vasoconstriction
at high ADH concentration and extreme dehydration ADH causes vasoconstriction which increase blood pressure
