Body Fluids and Kidneys Flashcards
What are two sources of intake of H2O
How much you drink
Molecular H2O from metabolism
Two output of H2O mechanisms
Insensible: not conscious loss of H2O
Respiration- breathing out: losing H2O from lungs
What percent of BW is water?
Extracellular fluid?
Intracellular fluid
What is a third source of fluid?
60 percent BW=water
20 percent BW= extracellular
40 percent BW= intracellular
Transcellular fluids (synovial, peritoneal, pericardial)
Blood volume is what percent of BW
7 percent of body weight
Ionic composition of plasma and interstitial fluid is similar except for…
Why?
PROTEIN
Plasma membrane highly permeable to water and ions
Low permeability to proteins
Donnan effect of negatively charge plasma proteins
Intracellular and extracellular separted by cell membranes which is highly permeable to what but not what?
Permeable to water but not to most other electrolytes
What can be used to measure fluid volumes in different body fluid compartments?
Radioactive isotopes
Relationship between moles and osmoles?
Moles= concentration of molecules
Osmoles= concentration of osmotically active molecules
(glucose vs NaCl….NaCl completely dissociates=2 mOsmol…glucose=1 mOsmol)
1 mOsmol/L of impermeant solute causes ____ osmotic pressure
19.3 mmHg
T/F Tonicity takes into account the total concentration of only penetrating solutes
F
Non-penetrating
What’s an example of a substance that can penetrate membrane?
Urea
Isosmotic
Osmolarity same as cell regardless of whether solute can permeate membrane
Hyperosmotic and hypoosmotic
Osmolarity higher or lower than cell regardless of whether solute can permeate
What happens to cell dropped in hypertonic saline solution
ECF increases
ICF volumes decreases
Cell shrinks
Hyponatremia
Low plasma sodium
Cell swells
