body fluids, diffusion and osmosis Flashcards
19.08.08
Of the body how much of it is water? where is this water use in the measurment?
50-70%
- water comes from (60% of weight is water)
- ICF-40%-2/3 of TBW
- ECF-20%-1/3 of TBW
- intestitial fluid
- plasma-1/4 of TBW
60-40-20
what are some clinical aproaches for managing wate?
- burns
- 486000 in 2016
- bleeding
- 10.8 mil car accidents in 2009
- cholera- induced diareah
- 1.4 -4 mil in 2013
total body water for males vs females
- males
- 60
- females
- 50
this is due to the fat:water ratio
What % of body tissue is water
- 100% of body
- muscle
- 79-80% h2o
- fat
- males
- 10-15
- female
- 20-24
- males
- bone
- rest
- muscle
body fat measurment
- Dual energy X-ray absorptiometry
- uses
- conductivity difference allow body fat estimation through impedance
- uses
- general recommendations
- age and gender dependent, b/c of difference anatomically
what is plasma?
what is the hematocrit
blood devoid of cells.
Hematocrit = concentration of blood cells
- varies with age
1.
what is the difference between osmolarity and tonicity?
define the three states of tonicity with osmolarity as a reference.
these are not interchangeable.
- osmolarity
- the total solute concentration in an aqueous solution
- tonicity
- the effects of carious osmotic solutions on cells
the nature of the solues is often as important os the total osmolarity
- hypotonic
- the solution is hyposmotic, more stuff intracellularly than extracellularly. cuasing the cell to swell with water
- isotonic
- isosmotic- ICF and ECF are equal in osmolarity
- hypertonic
- solution is hyperosmotic, containing more solutes than the intracellular compartment
what is the composition of body fluids
compare ICF to ECF
- non-electrolytes-uncharged moieties
- glucose
- lipids
- creatine
- urea
- uncharged proteins
- electrolytes-charged moiteies
- salts
- acids/bases
- charged proteins
ICF vs ECF
- ECF electrolytes
- cation
- Na
- anion
- chloride
- protein
- lower
- cation
- ICF electrolytes
- cation
- K
- anion
- phosphate
- protein
- higher
- cation
list the values of each
- TBW-total body water
- male vs female
- TBW caluculations
- ECF (X/Y)and BPV% TBW
- male TBW>female TBW
- 60 vs50
- TBW=ECF + ICF; ECF =BPF+ISF
- blood plasma fluid
- interstitial fluid
- ECF=1/3 TBW; BPV=12% TBW
how much is a 1mmol/L? how can you use the molecular weight?
explain an equivelent. use Na+, Cl- and Ca++ as examples
explain %solution. use 10%NaCl, vs 1Liter
this is a unit of measurement called molarity
- 1mmol/L = 0.001mol/L
- mmol/L x 1mol/1000mmol x grams(MW)/mole = g/L
equivelent
- Eq/L = mol/L xcharge/atom
- example
- Na+ 135mmol/L=135mEq/L
- Cl-
- 108mmol/L=108mEq/L
- Ca++
- 2.1mmol/L=4.2 mEq/L
- example
% Solution
- grams of soulution/100mL, expressed in g/dL(deciliter)
- example
- 10% NaCl
- 10grams of NaCl in 100mL
- 1 liter = 10x’s -> 100g/L
- 10grams of NaCl in 100mL
- 10% NaCl
how are the measurments of Osmolarity used? explain
- osmole
- osmolarity
- 15mmol/L NaCl-> solution
- 15mmol/L Ca++-> solution
- osmolality
- Osmole is the number of moles of a solute tht contribute to osmotic pressure
- osmolrity
- Osm/L of solvent= [S] x D
- D= number of particles
- independent of charge
- example
- 15mmol/L NaCl-> 30mOsm/L solution
- 15mmol/L Ca++-> 15mOsm/L solution
- Osm/L of solvent= [S] x D
- osmolality
- difference from osmolarity: water volume function of temp while mass is not.
- Osm/kg h2o
calculate the following osmolarity
- Ca++
- 2.1-2.8mmol/L
- Na+
- 135-145mmol/L
- glucose
- 5mmol/L
- NaCl
- 5mmol/L
- Ca++
- 2.1-2.8mmol/L=4.2-5.6mEq/L
- 2.1-2.8mmol/L=2.1-2.8mOsm/L
- calcium does not dissociate,
- Na+
- 135-145mmol/L=135-145mEq/L
- 135-145mmol/L-135-145mOsm/L
- Na+ on its own does not dissociate
- glucose
- 5mmol/L=5mOsm/L
- glucose does not dissociate
- 5mmol/L=5mOsm/L
- NaCl
- 5mmol/L=10mEq/L
- 5mmol/L=10mOsm/L
- NaCl does dissociate in to sodium and chloride, so the solutions osmolarity is doubled
diffusion is an important concept in the body.
Explain the diffusion rate. what is the consequence on the vasculature?
calculate myoglobin if its MW is 68000
diffusion rate is proportional to 1/distance^2
- O2 will diffuse 100microns in 2.38 seconds, 6.6 hours to diffuse 1cm
- the vasculature will find itself densely through out the body and within 100microns of a cell
the higher the temperature= faster the diffusion
where it takes O2 2.38s to traverse 100microns, it will take myoglobin 1.2 minutes
why is it that measuring the plasma osmolarity tells us about the molarity through out the body?
at equilibrium osmolarity in the ECF = ICF
what is tonicity a function of?
tonicity is a function of permeability of the membrane.
is the solute can move accross into/out of the cell, the osmolarity of ICF and EFC changes. This leads to osmosis.
what is the length of time to achieve osmotic equilibrium through out the body. Why?
- ECF and ICF
- seconds to minutes
- whole body
- ~30min
- takes time to absorb the fluid into the gut