Term
| this is the function of the kidneys |
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Definition
| maintain balance between fluid intake and fluid loss & keeping electrolyte levels within limits tolerable to life, with enough reserve capacity to deal with extreme situations |
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Term
1)water or food ingestion 2.1 L/day
2)carbohydrate metabolism 0.2 L/day |
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Definition
| what are the sources of fluid intake? give an average of how much per day. |
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Term
1) Sensible fluid loss:
Sweat - 0.1 - 2 L/day
Feces - 0.1 L/day
Kidneys - 0.5 - 20 L/day (yes, the book said 20)
2) Insensible fluid loss:
Evaporation from lungs and skin(diffusion) - 0.7 L/day |
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Definition
| What are the two types of fluid loss? Give examples of each and the average amount of fluid lost per day from each type. |
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Term
Extracellular: about 1/3
Intracellular: 2/3 |
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Definition
| What fraction of your body fluid is extracellular? intracellular? |
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Term
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Definition
| What is the primary means of regulating fluid output? |
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Term
| 60% or 42 L in a 70 Kg person |
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Definition
| what percent of a person's body weight is made up of water? |
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Term
1) interstitial fluid (3/4 of extracellular fluid)
2) blood plasma (1/4 ~3L)
remember: plasma = non-cellular portion of blood that mixes with the interstitial fluid via pores in capillary membranes, so their composition is similar EXCEPT blood plasma has more proteins because capillaries are fairly impermeable to proteins and leak only a little into the interstitium |
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Definition
| What are the 2 main compartments of extracellular fluid? |
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Term
K+, Mg 2+, SO4, Phosphates, AA's, proteins
Extra: Na, Cl, HCO3, Ca++, Glucose |
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Definition
| What are the main intracellular ions? extracellular? |
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Term
intra: 28 L
extra: 14 L
-plasma: 3 L
-interstitium: 11L |
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Definition
| In a 70 Kg person, how much fluid is intra cellular? how much is extra (total? How much in the plasma? interstitium? |
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Term
we don't have to calculate this but we might need to know it:
(mls indicator injected x concentration) / compartment concentration |
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Definition
| what is the equation for total body fluid(using the indicator dilution method)? |
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Term
1)if the indicator disperses only in the compartment measured
2) Indicator disperses evenly in compartment
3) indicator not metabolized or excreted |
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Definition
| when is the indicator dilution method valid? |
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Term
1)total body water
-via D2O, 3 H2O, antipyrine
2) extracellular fluid volume
- via 22Na, inulin, thiosulfate
3) plasma volume
- via 125I-albumin, Evans blue dye |
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Definition
| what things are directly measured by the indicator dilution method? |
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Term
1) intra cellular fluid volume
total body H20 - extracellular fluid vol
2) blood volume
plasma vol / (1 - HCT) [51Cr-red blood cells]
3) interstitial fluid volume
extracellular fluid volume -plasma volume |
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Definition
| what things are measured indirectly(calculated) via the indicator dilution method? give their equations |
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Term
| osmotic forces (mainly from electrolyes) |
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Definition
| what determines fluid distribution across a CELL membrane(interstitial fluid - interstitial fluid)? |
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Term
1) hydrostatic forces
2) colloid osmotic forces (Starling's EQ) |
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Definition
| what determines fluid distribution across capillaries (plasma - interstitial fluid)? |
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Term
osmotic: moves fluid to higher solute concentration
hydrostatic: The pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity (remember the lungs? at the bottom this forces fluid out of the capillaries because of the weight, but at the top of the lungs this force is lower)
colloid osmotic: protein in blood plasma that tend to pull fluid into the circulatory system |
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Definition
which direction do each of these forces move fluid?
osmotic forces, hydrostatic forces, colloid osmotic forces |
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Term
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Definition
| diffusion of water across a selectively permeable membrane from a region of high water concentration to one of lower water concentration |
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Term
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Definition
| amount of pressure required to PREVENT osmosis |
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Term
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Definition
| do hydrostatic forces have a large or small effect on fluid movement across membranes? |
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Term
| the intracellular compartment is bigger that the extracellular compartment. Both sides will have the same concentration of water however |
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Definition
| because H2O moves across cell membranes easily (passively diffuses), why is there generally more fluid in the intracelluar fluid? |
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Term
| EXTRACELLULAR FLUID (meaning the plasma and interstitial fluid) |
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Definition
| when discussing loss of electrolytes, which fluid compartment is being described? (remember that solutes are relatively impermeable to cell membranes) |
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Term
intra: K+
extra: Na+
plasma: has about 20 mmHg difference due to proteins (colloid osmotic force) |
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Definition
| intracellularly, what ion creates the most osmotic pressure? extracellularly? the plasma vis interstitium? |
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Term
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Definition
| osmotic pressure difference between 2 solutions separated by a semipermeable membrane |
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Term
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Definition
| concentration of osmotically active particals in solution expressed as osmoles/L |
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Term
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Definition
| concentration of osmotically active particals of solute/kg of solvent |
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Term
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Definition
| solution with the same concentration as the ECF (300 mOsm/L) |
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Term
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Definition
| solution in which the cell volume stays the same |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| give two examples of solutions that neither shrink nor swell cells (isotonic solutinos) |
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Term
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Definition
| what is the only reason for fluid to move across a cell membrane? |
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Term
| swell ( by definition, the solution has less osmotically active particals, water will rush into the cell) |
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Definition
| a cell placed in a hypotonic solution will do what? |
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Term
| shrink (there are more osmotically active particals in the fluid than the cell, water will rush out of the cell to balance it) |
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Definition
| a cell placed in a hypertonic solution will do what? |
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Term
gram molecular weight / (# of particles/L H2O)
so 58.2/2 since NaCl dissociates
=29.3 g/L |
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Definition
| how do you calculate 1 osmole of NaCl? |
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Term
29.3 g/L * 0.3 Osm/L = 9 g/L
9 g ~ 9 mL so 9ml/ 1000 L = 0.9%
0.3 comes from body fluid being 300 mOsm/L or 0.3 Osm/L
Osm = g/L so g/L * g/L/L = g/L? I am bad at math...
note: 1g ~ 1mL because density of H2O =1 |
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Definition
| so if 1 osmole of NaCl is 29.3 g/L, how do you make an isotonic solution? |
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Term
3% is > 0.9%(isotonic) SO the solution MUST be hypertonic
since NaCl is not permeable and plasma is 300 mOsm/L (you could calculate it, but we don't have to for the exam) |
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Definition
| if you have a 3% solution of NaCl is it hypertonic, hypotonic, or isotonic? |
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Term
since we have 150 mOsm + 300 mOsm, we have a solution that is > 300 mOsm so the solution is hypertonic and the cells will shrink
HOWEVER, because glycerol is permeable to cell membranes, once it diffuses, the cells will return to normal size as the solute (glycerol) balances the water by moving back into the cell |
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Definition
| What will happen to skeletal muscle cells immersed in a solution containing 150 mOsm NaCl and 300 mOsm glycerol/L? |
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Term
| since NaCl does not pass through the membrane, only the ECF will expand in volume. The osmolarity is the same, so no water movement. |
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Definition
| what happens to osmolarity, ICF vol. and ECF vol. when an isotonic NaCl solution is infused? |
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Term
| water will go to both ICF and ECF equally, and osmolarity will decrease overall because there is less relative solute to water |
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Definition
| what happens to osmolarity, ICF vol. and ECF vol. when water (or a hyPOtonic solution) is infused? |
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Term
since there is an increased osmolarity in the ECF now, water from the ICF diffuses out, increasing the osmolarity inside the cell to match outside.
so ECF vol. increases and ICF vol. decreases
note: osomlarity will change on BOTH sides the same way because water is permeable and will always move to balance the osmolarity gradient |
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Definition
| what happens to osmolarity, ICF vol. and ECF vol. when a hypertonic NaCl solution is infused? |
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Term
1. is the solute in the solution hypo, iso, or hypertonic ( iso = 5% glucose, 0.9% NaCl) body fluid is 0.3 Osm/L or 300 mOsm/L <-- both ECF and ICF (remember osmolarity should always match inside and outside because water is free to diffuse)
2. which way will the water move? in other words: which side has more solute in it now? outside or inside?
3. Will that solute move? is it permeable?
4. Once the water moves is one area more or less diluted/concentrated than it was to start? more concentrated = increase in osmolarity |
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Definition
| what's an easy way to solve the fluid volume/osmolarity problems? |
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Term
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Definition
| if there is water loss or excess Na in someone it is called ___ |
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Term
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Definition
| is there is excess water or loss of Na in someone it is called |
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Term
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Definition
| excess fluid in body tissues |
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Term
1) high capillary hydrostatic pressure
2) decreased plasma proteins (low oncotic pressure
3) increased capillary permeability
4) blockage of lymphatics |
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Definition
| what 4 conditions cause edema? |
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Term
| the axillary lymph nodes were removed, so the lymphatic drainage was effectively blocked from her arm causing fluid to back up into the interstitium |
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Definition
| when the lady had a radical mastectomy, why did her arm swell? |
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Term
FR= Kf (Pc - Pisf - PIc - PI isf)
Kf = filtration coefficient
Pc = capillary pressure ( moves fluid out capillary)
Pisf = Interstitial fluid pressure ( moves fluid into capillary)
PIc = plasma colloid osmotic pressure (retains fluid in capillary)
PIisf = interstitial colloid osmotic pressure (how much the proteins in the interstitium pull fluid back out of capillaries) |
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Definition
| what is the equation for capillary filtration rate? |
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Term
1) increase capillary filtration
2) failure of lymphatics to return interstitial fluid to circulation |
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Definition
| what can cause increased interstitial (extracellular) fluid volume? |
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Term
1)Na/K+ pump failure (Na leak into cells, can't get out) this can be due to lack of nutrition (ATP) to the cell or depression of metabolic systems
2) inflammation (toxic conditions or burns destroy the cell membrane) |
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Definition
| what can cause increased intracellular fluid volume? |
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Term
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Definition
| most common cause of edema |
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Term
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Definition
____ is characterized by
1) increased capillary filtration
2) decreased salt and water excretion by kidneys (compensating for blood pressure)
-this leads to increased blood volume and increased BP which increases capillary pressure (filtration)
positive feedback/viscious cycle! |
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