Body Fluids Compartments Flashcards
True or false? the body is a closed system
false; open - exchanges material and energy with surroundings
What is the water steady state?
the amount of water coming into the body each day must equal the amount of water eliminated from the body over the same period of time. If not, the body will have either a net water gain or loss
What are the 3 water sources?
water drinking, water in food, metabolism to CO2 and H2O
What is insensible H2O loss?
evaporation from respiratory tract and skin surface
At normal room temperature, sweating accounts for ___ % of heat losses.
25
What are pathological losses of water?
vascular bleeding, vomitting, diarrhea
How do Na+ and K+ normally enter body?
food
These are substances which are chemically altered and must also be in balance, but the amount ingested will not have a simple one to one relationship to the amount eliminated
metabolized substances
Distribution of various substances within the body is homogenous. True or false?
false - NOT HOMOGENOUS
Compartments are frequently spatially dispersed, and all the parts of a compartment need not be in contact with each other. True or false?
true
How is the gram molecular weight of a molecule calculated?
by summing the atomic weight of its individual atoms
What is the most common solvent?
water
This is concentration expressed as moles solute per kg of solvent
molality
This is concentration expressed as moles solute per liter of solution
molarity
For monovalent ions like sodium and chloride, ___ equivalent is equal to one GMW. For divalent ions like calcium, magnesium, and HPO42-, one equivalent is equal to ___ GMW.
1; 0.5
In regards to complications in plasma concentrations, 50% of calcium is bound to ___ and ___ in the blood
albumin; citrate
What is the name for the following situation: the clinical lab reports show low plasma sodium when in fact it is normal.
pseduohyponatremia
note: plasma volume is only 93% water, the other 7% is protein and lipid. Thus, ionic concentrations in plasma water are somewhat underestimated when expressed in terms of whole plasma
Total body water makes up approximately __-__% of body weight in adult males and somewhat less in adult females
55-60
Intracellular fluid is approximately ___% of body weight
36
Extracellular fluid is approximately __% of body weight
24
A typical extracellular volume is about ___ L
17
A 70 kg man has a plasma volume of about __ L which is about 4.5% of body weight
3
A 70 kg man has an interstitial space of about ___ L. This is about 11.5% of body weight.
8
note: the remaining 6 L is extracellular fluid in minor compartments
This is the fraction of blood that is cells
hematocrit
Plasma volume = ?
blood volume x (1 - Hct)
Plasma water is the initial ___ ___ point for ingested nutrients and the ___ point for waste products
body access; exit
True or false? the ionic composition of extracellular and intracellular compartments is markedly different, however, the total osmotic concentrations of extracellular and intracellular fluid are similar
true
the principle extracellular cation is ___. The principle extracellular anions are ___ and ___
Na+; chloride; bicarbonate
the principle intracellular cation is ____. The principle intracellular anions are ___, ___, and ___
K+; phosphates (HPO4, H2PO4); organic (ATP); proteins
Particles that dissociate to form ions exert an osmotic force in proportion to what?
the number of osmotic particles formed
ex: 1.0 mole of NaCl forms 2.0 osmolar solution; CaCl2 forms a 3.0 osmolar solution
Except for ___ proteins, all ions can cross the capillary endothelial cell membranes.
plasma
An increase in plasma protein concentration causes water to move from ___ into the ___
interstitium; plasma
A decrease in plasma protein concentration causes water to move from the ___ to the ___
plasma; interstitium
membrane pumps effectively keep ___ from entering cells
Na
The osmotic force generated when there is an increase in extracellular sodium concentration causes water to move where?
out of the cell and into the extracellular space
What is the Gibbs-Donnan Membrane equilibrium?
proteins are negatively charged anions. Because the proteins cannot move, the distribution of other ions is influenced in an attempt to maintain electroneutrality as well as osmotic equilibrium on the two side of the membrane
Diffusible cation concentration is ____ in the compartment containing non-diffusible, anionic proteins. Diffusible anion concentration is ____ in the compartment containing the non-diffusible, anionic proteins
higher; lower
The total osmotic force exerted by diffusible ions is ___ in the protein-containing compartment than in the protein-free compartment
greater
note: there are more diffusible ionic particles in the protein-containing compartment - this extra osmotic force from diffusible ions is added to the osmotic force exerted by the anionic proteins
What is the end result of the Gibbs-Donnan effect?
more water moves into the protein-containing compartment than would be predicted on the basis of the protein concentration alone
Amount injected / volume of distribution = ?
concentration
Volume of distribution = ?
(amount injected - amount excreted) / concentration after equilibrium
Deuterated water, titrated water, and antipyrine are commonly used to measure the volume of what?
total body water
labeled insulin, sucrose, mannitol and sulfate are commonly used to measure the volume of what?
extracellular fluid volume
Radiolabeled albumin or evans blue dye are commonly used to measure the volume of what?
plasma volume
TBW - ECFV = ?
ICFV
ECFV - PV = ?
ISFV
Redistribution of water between the extracellular fluid compartments is determined by the balance of what forces?
starling forces
Changes in intracellular fluid volume occur in response to changes in what?
extracellular fluid osmolarity, but not in response to isosmotic changes in extracellular fluid volume
If a primary disturbance causes ECF osmolarity to increase, water moves where?
out of cells and the cells shrink
note: the total body osmolarity remains higher than normal
If a primary disturbance causes ECF osmolarity to decrease, water moves where
into the cells and the cells swell
note: the total body osmolarity remains lower than normal
Under normal conditions, ECF osmolarity can be roughly estimated as?
Posm = 2 x [Na]p = 270-290 mOsm
The measured plasma osmolarity measured by the clinical laboratory can be estimated as?
Posm(measured) = 2 x [Na]p + [glucose]p/18 + [BUN]p/2.8
note: BUN signifies blood urea nitrogen
What are the ineffective and effective osmoles?
ineffective: urea
effective: glucose, Na+
Effective osmolarity is given as?
Posm(effective) = 2 x [Na]p + [glucose]p/18
or
Posm(effective) = Posm(measured) - [BUN]p/2.8
What is the osmolar gap?
if the clinically measured osmolarity is higher than that calculated using the equation, it suggests the presence of an unmeasured substance in the blood - occurs with ingestion of foreign substance
Calculate the initial total body solute as:
plasma osmolarity x total body water
calculate the initial extracellular solute as:
plasma osmolarity x extracellular volume
calculate the new total body solute as:
previous amount + added amount
calculate the new total body water as:
Old TBW + added water
calculate the new total body osmolarity as:
new total body solute divided by new TBW
calculate the new extracellular solute as:
old extracellular solute + added extracellular solute
calculate the new extracellular volume as:
new extracellular solute divided by new total body osmolarity
calculate the new intracellular volume as:
new TBW - New extracellular volume
Hypernatremia is generally indicative of ____ intracellular fluid, while hyponatremia is generally indicative of ____ intracellular fluid
decreased; increased
In the presence of severe hyperglycemia, the glucose acts as an effective osmole and can induce ____ and cell ___
hyponatremia; cell shrinkage
note: the cell shrinkage needs fixed, not the hyponatremia
With increased insensible water loss, excessive sweating, and central or nephrogenic diabetes insipidus, and decreased ADH secretion, ___ extracellular osmolarity is present
increased
note: hypernatremia
Increased central venous pressure in conjunction with edema is often indicative of what?
increased ECF volume
What is the main danger of decreased ECF volume?
hypolvemia, which ultimately decreases tissue perfusion
What is the clinical presentaiton of hypolvemia?
dry mucous membrane, lack of urination, tenting of skin, slow capillary refill
Vomiting, diarrhea, bleeding, and burns are conditions tending to cause what?
isotonic decreases in extracellular fluid volume with little direct effect on cell volume
This type of solution has the same osmotic concentration as plasma
isotonic
note: administration will tend to contract intracellular volume
This type of solution has a greater osmotic concentration than plasma. Administration will tend to decrease intracellular volume
hypertonic
This type of solution has a lesser osmotic concentration than plasma. Administration will tend to expand intracellular volume
hypotonic
In dextrose solutions, ___ is rapidly metabolized to CO2 + H2O. The volume therefore is distributed intracellular and extracellularly
glucose
For each type of saline solution, give its % of concentration
hypotonic
isotonic
hypertonic
hypotonic saline: 0.2%
isotonic saline: 0.9%
hypertonic saline: 5%
What is dextrose in saline used for?
volume replacement and caloric supplement
