Homeostasis Flashcards
How much of body mass is TBW ?
60%
What is the muscle tissue distribution ?
43% water and 76% tissue
What is the muscle tissue distrubution in Adipose ?
10% Water and less than 10% Tissue
What are the three sources of fluid intake ?
Oxidative matabolism, water content in food and drink.
What are the sources that excrete fluid from the body ?
Urine Insensible persperation and feces.
How much does the normal person sweat in a day ?
100ml / day
In the skin and lung 700ml / day
What are the open fluid compartments ?
Lung Kidney GI tract and Skin
What are the fluid Compartments ?
Intracellular Fluid, Extracellular Fluid (Plasma and Interstitial fluid)
What percent of body mass is made up of blood ?
8%
What are the fluid barriers in the body ?
Capillaries and cell membranes.
What are the major cations and anions of the interstital compartment ?
Na is the major cation and Cl is the major anion.
What is the major cation in the ICF ?
K+, Protein Bicarbonate and phosphate are the major anions.
What are the major anions in the ECF ?
Cl and PO4
What are the 5 criteria for a probe that make it useful to measure body fluids ?
- Nontoxic at the concentration you will employ
- Neither synthesized or metabolized
- Disperses evenly in the fluid
- Disperses only in the compartment of interest.
- Does not influence fluid compartment volume
What is the probe to measure plasma volume ?
Evans Blue
How is plasma volume measured.
A certain quantity of Die injected, Q. Blood is drawn and plasma is extracted so the probe concentration can be measured.
What is the formula to measure Plasma Volume ?
PV= Q / (Q/V)
What is blood volume equal to ?
PV / (1- hematocrit)
What is the probe to measure ECF ?
Inulin thiosulfate or Na+
What is the formula for ISF ?
ISF = ECF - PV or TBW - ECF
How do you correct when some of the probe is excreted in the urine ?
You subtract the urin concentration from the total die you injected.
WHat is used to measure Total Body water ?
Radioactive H2O
If you put one mole of NaCl into a L of solution what will the osmolarity be ?
2 Osmols of salt in 1 L
What is the formula for osmolality ?
Osmol / Kg solvent
1 Osmole of glucose Per Liter =
1 Osmolar Glucose Solution
What is osmotic pressure ?
The precise amount of presure required to prevent the osmosis. Or amount of pressure that must be applied to prevent the net diffusion of water through the membrane.
What is the relation of osmotic pressure to osmolarity ?
Osmotic pressure of a solute is directly proportional to concentration of osmotically active particles in that solution.
What is the osmolarity gap ?
When your measured plasma osmolarity is greater than the estimated plasma osmolarity.
How do you estimate plasma osmolarity ?
Plasma Osmolarity = (Plasma Na x 2) + Glucose + Urea
What is the normal plasma osmolarity ?
What is the plasma osmolarity in a dehydrated patient ?
320 for example. An increase
What are the 4 steps for calculating fluid for infusion of treatment ?
- Calculate the ECF and ICF volume
- Calculate the total mOsmoles in ECF and ICF.
- Calculate the fluid volume necessary to achieve concentration of 280 mOsm
- Calculate the fluid you will need to add.
**Remember you are titrating the patient. Not infusing all at once.
What are the fluid options for patients ?
Water
Isotonic Saline
Glucose Solution
Hypotonic Saline with Glucose.
What will infusion with Isotonic Saline do ?
Increase in ECF volume without a change in osmolarity
No change in volume or osmolarity of ICF.
What will a glucose solution do ?
A glucose solution will increase the colume of the ECF, cause a decrease in ECF osmolarity, and flux water into the ICF. It will increase the colume of all compartments and decrease the osmolarity of all compartments.
Is glucose a permeable ion ?
Yes, It is semi permeable.
Na is the major Cation and Cl is the major anion
ECF
What is the Gibbs Donin Effect ?
There is slightly less concentration of Cl- and HCO3- in the plasma because protein can not pass the capillary to the interstital fluid. The ( - ) charge in the protein will drive the Cl and Bicarb across the permeable capillary.
What is the major cation in the ICF ?
What other ions are in high concentration ?
K+
Mg2+ and PO4-
Is Ca2+ in the ICF ?
NO
What causes movement of fluid from the plasma to the ICF ?
Hydrostatic pressure
What causes movement of fluid from the ICF to the plasma ?
Oncotic or collidal pressure. The protein concentration will draw fluid from the ICF to the plasma to equalize the concentration.
Is Na permeable ?
No Na is impermeable
Is Urea Permeable ?
Yes.
Is water permeable
Ya, if you missed this your a dumbass
Is glycerol permeable ?
Yes it is slowly permeable
If you see a decrease in ICF and ECF with a general increase in Osmolality what would you infuse the patient with ?
You will give saline with glucose in it. This will increase the ECF and the glucose will permeate the cells and cause the water to follow and enter the ICF. It lowers the oncotic pressure in the ECF.
What is the min and max urinary output per day ?
Min is 0.5 L / Day
Max is 20 L / Day
What separates the interstitial fluid from the plasma ?
Capillary
Can proteins pass through the capillary wall ?
No that is why they are present in the plasma but not the intersitial fluid
