Tema 2 Flashcards
water percentage
- different parameters
50-60% os body mass in adults
AGE: newborns have a higher % than aduts
SEX: women are 55% fluids, men 60%
ORGANS: brain> liver> muscle> skin> bones> fat
CORPORAL LIQUID COMPARTMENTS
Not homogeneous
2/3 in the intracellular liquid
1/3 in the extracellular liquid
- 80% intersticial liquid
-20% plasma
-transcelullar liquids
SEMIPERMEABLE MEMBRANES
Plasmatic: separates ICL and ECL
Endothelium: separates plasma and intersticial liquid
FLUIDS ARE IN CONSTANT MOVEMENT, VOLUME IS CONSTANT
differences of the extracellular liquid
plasma has more protein anions than the interstitial liquid
plasma has less Cl- than the interstitial liquid
plasma and intersticial have aprox the same concentration of Na+
units of concentration of ions
mEq/ L
mmol/ L
chemical differences between ECL + ICL
Na+
Na+: 142/ 10
chemical differences between ECL + ICL
K+
K+: 4/ 140
chemical differences between ECL + ICL
Ca2+
2,4/ 0,001
chemical differences between ECL + ICL
Mg2+
1,2/ 58
chemical differences between ECL + ICL
Cl-
103/4
chemical differences between ECL + ICL
HCO3+
28/10
chemical differences between ECL + ICL
(PO4)3-
4/75
chemical difference ECL + ICL
glucose and proteins
C6H12O6: 90/ 0-20
a. acids: 30/200
units: mg/dl
OSMOSIS definition
movement of water particles form a high water potential to a low water potential through a semipermeable membrane
It’s the main mechanism through which water moves
When there is a difference in concentration of a non-diffusible substance
the balance between two compartments requires (osmosis)
Adequate amount of water
Adequate amount of electrolites
osmotic equilibrium
osmotic pressure
ECL + ICL are in osmotic equilibrium
• Osmotic pressure in ECF depends 80 % of Na+ and Cl-.
• Osmotic pressure in ICF , depends 50 % of K+ and the rest divided by other substances
The volume flow through a membrane is determined by the equilibrium between the hydrostatic and osmotic pressures on both sides of the membrane.
isotonic, hypertonic, hypotonic solutions
hypertonic: water moves from ICL to ECL as it has more solutes (ECL)
- cells decrease volume
hypotonic: water moves from ECL to ICL as it has less solutes/ more water
-cells increase volume
Distribution of a fluid through the membranes of a capillary
Pc +πi = Pi +πp
P: hydrostatic pressure
π: coloidosmotic pressure
fluid quantification
-plasmatic and ECF volume
plasmatic volume: blue Evans or radioactive elements
–> they bind to plasmatic proteins, but not red blood cells
ECF volume: substances that diffuse easily but don’t enter the cell, such as radioactive elements
