Lec 3 Physiology basics Flashcards
How do you calculate mMol/L?
mg of substance / formula weight / Liters
- tells you how many particles per L solution
How do you calculate mEq/L?
mMol/L * valence * # of molec
- tells you ionic charge of solution
How do you calculate mOsm/L?
mMol/L * number of particles
- tells you how many total particle to help figure out osmotic pressure
How do you calculate % solutions?
grams of substance per 100 mL
What is total body fluid volume?
40 Liters
What is extracellular and intracellular volume?
- 15 L extracellular
- 25 L intracellular
What is blood volume?
5 L
What percent of fluid volume is extracellular/intracellular?
extracellular = 1/3 of total fluid intracellular = 2/3 of total fluid
What percent of body weight is blood volume?
8% of body weight
What percent of body weight is water?
60%
What is normal osmolality?
300
What is normal extracellular pH?
7.37-7.42
What is major cation in extracellular space?
Na
What is major cation in intracellular space?
K
What are major anions in extracellular?
Cl, HCO3
What are major anions in intracellular?
primary anions are actually intracellular proteins
How does urine output change in different conditions?
changes to offset differences in sweat/feces/lung/etc in order to maintain water balance
What is the definition of osmotic pressure?
pressure needed to offset fluid movement based on osmosis
What characteristics make a certain particle an osmotic particle?
- solute needs to be dissolved [can’t be suspended]
2. has to be trapped on one side of a membrane
Does size or number of particles matter in osmotic pressure?
number of particles, not size
How many mmHg is 1 mOsm/L?
19.3
3 principles of water shift between body fluid compartments
- volume of compartment is determine by amount of solute it has
- water follows salt
- the body does not tolerate osmotic imbalances
Do NaCl/NaHCO3 stay extracellular or go into cell when you add them in solution intravenously?
Stay extracellular
Does K stay extracellular or go into cell when you add it in solution intravenously?
goes into cell
Does glucose stay extracellular or go into cell when you add it in solution intravenously?
goes into cell
What is concentration NaCl in normal saline?
0.9% NaCl
Where does Na go when you inject intravenously with normal saline?
- Na goes to vascular and interstitial spaces
- Na does not get taken up into cell
Where does water go when you inject intravenously with normal saline?
Distributes with salt to extracellular [vascular + interstitial]
Does intravenous normal saline change osmolality of system?
- no, because its isotonic to plasma
Do volume/osmolality change in/out of cell when you inject with intravenous normal saline?
extracellular: no change osmolality, increase volume
intracellular: no change osmolality or volume
Where does Na go when you have high NaCl intake?
- goes to GI and then taken up by blood stream
- distributes to extracellular volume
- does not get into cell
How does high NaCl intake change osmolarity of extracellular fluid?
- increases extracellular concentration
Where does water go in high NaCl intake?
- water goes with salt into blood and interstitial
- water driven out of cell and into intracellular space to balance
Does high NaCl intake change osmolarity?
- will increase inside and outside of cell
- get equilibrium of osmolarity in/out of cell but both slightly elevated compared to normal
What happens to BP if you add fluid intravenously?
- BP determined by volume in vasculature
- if you inject any fluid intravenously, BP will go up and push fluid into interstitium
What kind of fluid are you losing in diarrhea?
isotonic
What kind of fluid is secreted in normal digestive process?
isotonic
what kind of fluid is saliva?
hypotonic
Does osmolarity change in diarrhea?
Nope!
In diarrhea is there a driving force to move fluid between intra and extracellular?
Nope!
What are two pathways of trans-epithelial transport?
- trans-cellular: through cells
2. paracellular: between cells
How is water transported from apical to basal surface?
- can transfer through or between cells
What proteins are required for trans-cellular water transfer?
aquaporins [water channels]
What is solvent drag? Where does it occur?
- driving force for water movement causes solvents and RBCS and anything in it to move with it
- occurs in capillary
