L2 BODY FLUID COMPARTMENTS Flashcards
What are the body fluid compartments?
What structure separates these compartments?
- Intra-cellular fluid (ICF)
- Extra-cellular fluid (ECF)
Cell membrane separates them.
What are the components of the extracellular fluid ?
What structure separates the components?
- Interstitial fluid
- Plasma fluid
3.Transcellular fluid (<1%)
Capillary wall separates them.
Where is transcellular fluid found?
This compartment includes fluid in the synovial, peritoneal, pericardial, and intraocular spaces, as well as the cerebrospinal fluid.
Percentage of total body weight in Extracellular fluid?
20%
What fraction of total body water is Extracellular fluid?
1/3
Percentage of total body weight in Intracellular fluid?
40%
Fraction of total body water in Intracellular fluid?
2/3
Fraction of ECF is interstitial fluid?
3/4
What fraction of ECF is plasma fluid?
1/4
What is the name of the principle used to measure fluid compartments?
Indicator Dilution Principle
The measurement of fluid compartments utilizes what formula?
𝐶𝑜𝑛𝑐𝑒𝑛𝑡𝑟𝑎𝑡𝑖𝑜𝑛 =
Amount (Mass) / 𝑉𝑜𝑙𝑢𝑚𝑒 of Distribution
Describe the principle used to measure fluid compartments?
It requires the introduction of a substance, of known conc. & amount (mass) into a particular compartment, allowing it to disperse evenly throughout the compartment’s fluid, and then analysing the extent to which the substance becomes diluted so as to calculate the volume of the other fluid compartment.
Total mass of a substance after dispersion in the fluid compartment will be the same as the total mass injected into the compartment.
Desirable characteristics of a substance used to measure fluid compartments?
(5)
- Measurable
- Remains in compartment (loss & metabolized)
- Evenly distributed within the compartment
- Does not alter water distribution
- Non-toxic
What substances can be used in the calculation of Total Body Water?
Deuterated water (D2O), tritiated water (THO), and antipyrine
What substances can be used in the calculation of Extracellular Fluid Volume (ECFV)?
Labeled inulin, sucrose and mannitol
What substances can be used in the calculation of Plasma Volume (PV)?
Radiolabeled albumin or Evans Blue Dye (which binds to albumin)
Formula to calculate Intracellular Fluid Volume (ICFV)?
Total body water – Extra cellular fluid volume