Chapter 25 Flashcards
What is insensible water loss?
-loss of water from breathing and diffusion throuh the skin
What components make up the total body water?
- intracellular fluid (ICF)
- Extra cellular fluid (ECF) (made up of the interstitial fluid (ISF) and the blood plasma)
What percenage of the body weight is total body water?
60%
What percentage of TBW is ICF?
40%
What percentage of the TBW is ECF?
20% (mostly from the ISF)
ISF+ Plasma volume= ?
ECF
What is transcellular fluid?
Water outside of the tissue
-CSF, GI Juices, bladder etc
What four organs are in direct contact with ECF and which 3 are resposible for maintaining internal environment?
-alimentary
-lungs
-kidneys
-Skin
What is the Intercellular v. extracellular concentration of Na+ ions?
14 and 140
What is the intracellular v. extracellular concentration of K+?
4 and 144(or 120)
How does one calculate the volume of a fluid compartment using a known volume and a concentration of a vertain compound and the known concentration retrieved?
V1xC1=V2xC2
so
V1 (unknown)= Volume of indicator x concentration of indicator (stock)/ concentration of the indicator retrieved
Conc.= Q/V
The indicator used for the measurement of body water must be:
- evenly dispersed
- stay in one compartment
- not metabolized or excreted
- nontoxic
- can not influence the volume the is being measured
Indicators used for TBW measurement:
3H2O, dH2O. antipyrine
Qualififcations for measuing ECF and types:
- have to disperse in the plasma and the ISF but can not pentrate the cells
- Radioactive Na, Cl, iodothalamate, thiosulfate or Inulin
- INULIN: filtered by the kidneys so the volume of inulin in the urine must be accounted for.
What is the equation to measure the ICV?
ICV= TBW-ECV
