Body fluids Flashcards
What are the two concepts of the “Milieu Interior” ?
1- Environment surrounding individual cells is vastly different from external environment
2- Internal environment remains relatively constant under condition of health
What is the most abundant single constituent of the body?
Water ( around 45% to 75% of the total body mass)
Obligatory vs Facultative losses
Obligatory losses: happens no matter what (around 1.5l/day.) Can be insensible or Sensible
Facultative losses: Vary with intake
Name the differences between insensible perspiration and sweating
Insensible perspiration: Pure water, entire skin surface, passive evaporation and continuous
Sweating: electrolyte solution, active secretion, sweat glans and activated by heavy work and high temp
What is a negative water balance ?
When the water loss is higher than the water intake
What can cause a negative water balance?
1- Reduced intake of water
2-Excessive loss from gut (ex. vomiting, diarrhea )
3- Excessive sweating
4- Excessive loss in expired air ( dry air at high altitudes)
5- Excessive loss in urine
What is water intoxication?
When the water intake is higher than the water loss
What can cause water intoxication?
1-Excessive water intake
2- Renal system failure
What is the extracellular fluid (ECF) and how much of the total body water does it represent?
The extracellular fluid is the liquid outside the cells of any multicellular organism
It represent 1/3 of the total body water
What is the intracellular (ICF) and how much of the total body water does it represent?
The intracellular fluid is the fluid within the cell (aggregate of fluid bound by internal surfaces of cell membranes)
It represent 2/3 of the total body water
What are the two major and two minor subcompartments of the extracellular fluid ?
Major: Plasma and interstitial fluid (ISF)
Minor: Lymph and transcellular fluid
What is plasma?
The fluid medium in which blood cells are suspended
What is the Interstitial Fluid?
The fluid which percolates between individual cells
What is Hematocrit (Ht)?
The percentage of blood volume that is occupied by red blood cells
How do we calculate the Hematocrit(Ht)?
heigh of erythrocytes column/heigh of whole blood column
Normal value is around 45%
What is the trans cellular fluid?
The aggregate of small fluid volumes secreted by specific cells into a number of body cavities
What is the milieu interieur?
the extracellular fluid in which the cells of the body are nourished and maintained in a state of equilibrium
What are the indicators that can be used to measure the total body water?
Antipyrine, D2O or T2O
What are the indicators that can be used to measure the plasma volume?
Evans’ Blue or I^131 -Albumin
What do we need to know for the indicator dilution method?
1- The total quantity of test substance introduced
2- The concentration of the substance/Unit volume of fluid after dispersing
What is the ionic composition of ICF (intracellular fluid)
High in K+ (and Mg++) but low in Na+ and Cl-
what is the ionic composition of ECF (extracellular fluid)?
High in Na+ and Cl- but low in K+
