Fluids Flashcards
What is the largest source of fluid entering the body?
Intake of water containing foods and beverages
What are examples of “insensible” fluid loss from the body?
- Lungs humidify the air as it comes in, and releases it during exhale
- Sweating
What are “sensible” ways in which the body losses water?
Urine
Diarrhea maybe
- What is the 60-40-20 Rule for the average male
- What is body weight % of water in males vs femals
- How many liters of water are inside the body?
- 60% of total body weight is water, 40% of total body weight is intracellular, and 20% of body weight is extracellular
- Lean male - 70%, Obese Woman - 50% (because they are predispositioned for more fat)
- 40 Liters
How many liters of H20 do most people injest in a day?
How many liters of water do most people lose in a day?
- 2.5 L
- 2.5 L
What organ is the primary site of H20 loss/gain regulation?
Kidneys
What are the 4 body fluid compartments? What are the boundaries of each?
-
Interstitial Space - fluid that bathes the cells of the body
- Boundary is everything cuz, this is sandwhiched between all of the other compartments
-
Intracellular Space - fluid within the cells of the body
- Boundary would be the double layered plasma membrane
-
Transcellular Space - fluid within specialized fluid spaces - like cerebrospinal fluid, pleural, synovial, peritoneal
- Boundary - epithelial cells (very hard to get into these…)
-
Plasma - fluid found within blood vessels
- Boundary - endothelial. Has small cleft opening that let molecules with a SMALL molecular weight pass through.
What is the reflection coefficient?
- The ability of a solute to pass through a barrier - reflected numerically
- 0 = free solute permeability
- 1 = impermeable solute
Rank these fluid compartment boundaries from most restrictive –> least restrictive
Endothelial
Plasma Membrane
Epithelial
Epithelial > Plasma Membrane > Endothelial
The composition of the plasma and interstitial fluid is very similar except for [] ….
Large MW proteins are found in the Plasma and not the interstitial fluid
[] is the primary mechanism of transport for the solutes within the body fluids
Diffusion
How is the majority of water moved throughout the body?
- Bulk Flow
- As teh heart pumps, water and dissolved solutes are pumped through the endothelial cells and into the interstitial fluid
- most of this water returns to the plasma but some of goes to the lymph system.
The lymph system is a [] of the extracellular fluid
Subset
Define these Fluids
- Total Body Water
- Intracellular Fluid
- Extracellular Fluid
- Lymph
- Plasma
- Interstitial Fluid
- Transcellular Fluid
- Total Body Water - all water within the body
- Intracellular Fluid - Fluid found within the boundary of the plasma membrane
-
Extracellular Fluid - Fluid found within the body outside of plasma membranes
- Lymph - fluid within the boundary of endothelial cells in the lumpahtic vessels
- Plasma - fluid within the boundary of endothelial cells in blood vessels
- Interstitial Fluid - Fluid located between the body fluid compartments
- Transcellular Fluid - fluid found within epithelial cell boundaries
T/F
Water moves via Osmosis to an area of High solute concentration to low solute concentration
FALSE
Its moves water from low solute concentration to high solue concentration
- The [] of the solution, is based on the number of particles after dissociation per volume of fluid
- The [] of the solution si based on the amount of charged solute per volume of fluid
- Osmolarity
- Equivalency
What molecules are found in a higher concentration within the Intracellular fluids?
Potassium
Proteins
Phosphates
What molecules are concentrated more in teh extracellular fluids?
Sodium (Na+)
Chloride (Cl-)
Calcium (Ca2+)
Bicarbonate
Which extracellular compartment would you expect to have a higher osmolarity, interstitial fluid or the plasma? Why?
- The Plasma
- Remember, the composition of the two is very similar except for the fact that the plasma has a large amount of large proteins….this drives the osmolarity of the plasma up!
Even though membrane potentials exist (the difference in positive/negative across the membrane), what is the overall charge of body fluids on any side of a barrier?
- The body fluid compartments must have the same concentration of cations and ions
- Therefore our compartments are electroneutral
What is the Gibbs-Donnan effect?
- It has to do with the fact that Large MW weight proteins remain in the plasma
- These proteins have a negative charge which attracts cations to the endothelial lining
- It also repels small anions towards the interstitial space
This redistribution of cationsa nd anoions is the Gibbs-Donnan effect. It does not have a substantial effect on charge balance or anything.
Describe the difference in intracellular concentration between a Hypotonic solution and a Hypertonic solution?
- Hypotonic - larger concentration of solutes in the cell
- Hypertonic - larger concentration of solutes in the surrounding fluid
Molecules considered to be [] do not penetrate the plasma membrane?
What are some examples?
- Tonic
- Na+, Cl-, K+
- inulin
Molecules considered to be []-[] can penetrate the plasma membrane…
What are some examples?
- Non-tonic
- Ethanol
- alcohol
What is the definition of an “Osmotic Solute?”
It can dissolve in water
You drop a cell into a hyper-osmotic solution, where would the concentration of molecules be and where would the fluids flow?
- Hyper-osmotic means there are osmotic solutes in the solution (could be tonic or non-tonic we aren’t told)
- So the fluids would flow out of the cell into the surround hyper-osmotic solution.
If a cell was placed in a hyper-osmotic solution of non-tonic solutes, where would the fluid flow and why?
- The fluids would basically create a dynamic equillibrium of sorts.
- Since non-tonic solutes can freely penetrate the cell, the fluid should evenly distribute itself across both the cell and the surrounding solution
- How many liters are in the intracellular fluid of the body?
- How many liters are in the Interstitial fluid of the body?
- How many liters are in the Plasma fluid of the body?
- How many liters are in the Transcellular fluid of the body?
- How many liters are in the Extracellular Fluid of the body?
- 25L (290 mOsm)
- 11 L (290 mOsm)
- 3 L (300 mOsm)
- 1 L
- 14 L
What are the 3 steps of the dye Dilution Method?
- A dye is injected into the plasma compartment
- The dye then must be given time to equilibriate and get to the targeted compartments?
- Following equilibration, the sampel is removed from the plasma compartment.
- Final concentration is measured in mg/mL
What dye is used to test the volume of the TBW (total body water?
Triated Water
What molecule is dyed to test the volume of the Interstial Fluid and Plasma Membrane?
Inulin
What molecule is dyed to test the volume of the Plasma?
Albumin is dyed with Evan’s Blue Dye
What is the equation to find the fluid volume?
Volume (mL) = Amount of dye/molecule injected (mg)/ Final Concentration ( mg/mL)
Can either of the Institial Compartment or Intracellular compartment be calculated directly with the dye dilution method?
No
You would need to do the dye dilution method on other compartments and do some math to figure out their volumes.
