Exam 1: Fluids & Electrolytes Flashcards
Cell Properties
Molecule: When two of more atoms combine to form substance (pos or neg charge, then is ATOM)
Ion: An atom carries electrical charge bc it has gained or lost electrons
Cation vs Anion
Cation: Positive charge bc its LOST electrons
Anion: Negative charge bc it GAINS electrons
Electrolytes
Occur when substance dissolved in solution (molecules split into electrically charged atoms or ions)
Think of miliequivalents to balance out
Body Fluid Compartments
Fluid in each of the body compartments contain electrolytes
Have to be in the right place and in the right amount with balance of electrolytes
Movement of electrolytes is better when PT is healthy
Body Fluid Compartments Pt. 2
Whenever an electrolyte moves out of a cell, another takes its place. Homeostasis has equal number of cations and anions.
Compartments separated by semi-permeable membranes
Intracellular compartment vs Extracellular compartment
Intracellular - IN the cell
Extracellular - OUTSIDE of the cell —Subcategories:
Intravascular compartment
Interstitial Fluids
Body Fluid
Transportation of nutrients to the cells and carries waste from the cells
body fluid is about 60% of body weights
10% loss is serious
20% is fatal
Constituents of Body Fluid
Mainly water and dissolved substances
Glucose, urea and creatinine do NOT dissociate into ions, stay in same form
Other substances DO dissociate (NaCl) more likely to move around.
Diffusion
Movement of particles in ALL DIRECTIONS though a solution
High to Low concentration
diffusion allows shifting to occur as long as permeable membrane allows for it
Osmosis
Movement of WATER (pulling movement)
Draws water from low concentration to High concentration though selective permeable membrane
Goal is to equal concentration
Filtration
movement of solutes and solvents with Hydrostatic pressure.
Pushing pressure, High pressure, to LOW pressure movement
Osmolality - # of active particles per liter/kg
normal osmolality just under 300 mOsm/kg
Hydrostatic Pressure
Force of fluid pressing OUTWARD against some surface (water in a balloon)
Different in hydrostatic pressure, filtration moves solutes from High to Low pressure (Capillary Dynamics)
Isotonic Solution
Equilibrium on both side of a selectively permeable membrane
0.9%NaCl is isotonic, bc it is isotonic to human cells (very little osmosis)
other isotonic solutions (5% dextrose in 0.225% saline and lactated ringers solution)
Hypotonic solution
solution contains lower concentration of salt than other solutions
If the cell is dehydrated, we give a hypotonic solution to re-hydrate the cell, the cell then fills up
HYPO - think HIPPO fat swollen cell filling with water
Hypertonic solution
solution has a higher concentration of solutes than another solution
Think cell shrinkage, movement out of the cell, if blood needs to be diluted
ex: 10% dextrose in water, %5 dextrose in 0/9% saline
Osmotic Pressure
Force that draws solvent from solution though a selectively permeable membrane to a solution with less solvent activity.
determined by relative # of particles of solute on side of greater concentration
Active Transport
Moving “against the current” and needs to use energy, or moving from area of low concentration to and area of high concentration
the energy for active transport supplied by metabolic processes in the cell
Body Fluid Excretion
Fluids leave by skin, lungs, GI tract and kidneys
KIDNEYS excrete largest amount of fluid
Skin fluid excretion
water lost though skin by DIFFUSION up to 300-400 ml per day (perspiration) avg/ per day is 100ml
Lungs fluid excretion
water is lost from lungs thru expired air which is saturated water vapor
300-400ml/day
GI tract fluid excretion
large quantities of water secreted into GI tract, but ALMOST ALL REABSORBED
200ml/day lost in feces. severe diarrhea will result in lost of fluids and electrolytes
Kidney Fluid Excretion
MAJOR role in regulating fluid and electrolyte balance
normal kidneys can adjust water and electrolytes leaving body
urine output about 1500ml/day, but depends on other factors
Body Fluid Replacement
2400 ml per day is amount fo fluid excreted
water enters thought drink, food and oxidation of foods
oxidation water gained in foods = amount lost in feces
Electrolytes in food and liquids, EXTRA ones will leave in urine (not needed)
Electrolyte Blance / Homeostasis
Balance of internal environment
What is lost, needs to be replaced
when there is an excess of electrolytes, we help them, but watch carefully
Electrolyte Blance / Homeostasis Pt II.
Kidneys - control balance in fluid and electrolytes
Adrenal glands - secrete aldosterone, controlling extracellular fluid volume by regulating sodium reabsorbed in kidneys
ADH - from pituitary gland, regulates osmotic pressure of extracellular fluid by regulating h2o reabsorbed by kidneys (increased fluid volume)
RAAS System
Decreased Kidney perfusion pressure –> Renin release -> Angiotensin I –>converting enzyme in lungs –> Angiotensin II –> increased BP, increased circulating volume, renal auto-regulation
Water will follow sodium bc of aldosterone release
ADH
Directs kidneys to hold water, increase circulating volume, decrease osmolarity of plasma, helps balance thru negative feedback
Best way to determine fluid volume
body weight
Fluid Volume Deficit
Dehydration where H2O and electrolytes are lost in same proportion
Treat: Fluid Volume restoration, eliminate cause
Hypovolemia
FVD (Fluid volume deficit)
fluid loss> fluid intake
Isotonic: H2O and E.Lytes lost in equal proportions (give isotonic solutions to replace)
Hypotonic: decrease in solutes, but not water, fewer electrolytes, total body fluid less than normal. moving from EXTRACELLULAR to INTRACELLULAR
Hypertonic: decrease in water, but not solutes, shift INTRA to EXTRA cellular to make blood more dilute.
Hypovolemia Etiologies
GI fluid loss: vomiting (GIVE Iso THEN Hypo)
Kidneys: Polyuria d/t DKA (GIVE Iso THEN Hypo)
Fever (GIVE Hyper) bc cells are getting more fluid than blood, restore circulating volume
Third Spacing: fluid stuck in interspicial spaces (ISO to correct circ volume)
decreased fluid intake (GIVE Iso THEN Hyper)
First fluid is to balance volume, 2nd fluid is to replenish cells or blood
