Physiology Of Body Fluid Flashcards
All solutes and water that enter or leave the body do so via what
The ECF
The ICF and ECF are in what, and what does this mean?
Osmotic equilibrium, which means H2O only moves between them when an osmotic pressure gradient exists
Equilibrium of ICF and ECF osmolality occurs primarily by what
shifts in H2O, NOT shifts in solute
What is the only fluid that can be acted upon directly to control its volume and composition
Plasma
Any control mechanism that operates on the plasma, then regulates what
The ECF
Define third spacing
Too much fluid shifts from the blood vessels (intravascular) into the nonfunctional area of cells between the tissues and organs. This leads to a dehydration
Water moves how
From an area of higer concentration (such as a hypotonic solution) to an area of lower concentration (such as a hypertonic solution)
Define nonelectrolytes
Contain covalent bonds that prevent them from dissociating in solution and therefore have no electrical charge
I.e. glucose, lipids, urea
Define electrolytes
Dissociate into ions in water
All body fluid cavities have aprox. The same osmolality which is what
Around 290 - 300 mOsm
What is the serum electrolyte of Na
135 - 147 mEq/L
What is the serum electrolyte of Cl
95 - 105 mEq/L
What is the serum electrolyte of K
3.5 - 5 mEq/L
What is the serum electrolyte of HCO3
22 - 28 mEq/L
What is the serum electrolyte of Ca
8.4 - 10 mg/dl
What is the serum electrolyte of Pi
3.0 - 4.5 mg/dl
What is the serum protein level of albumin
3.5 - 5.5 g/dl
What is the serum protein level of globulin
2.3 - 3.5 g/dl
What is the serum protein level of total proteins
6.0 - 7.8 g/dl
What is the serum level of creatine
0.6 - 1.2 mg/dl
What is the serum level of BUN
7 - 18 mg/dl
Blood contains both what
ECF (plasma) and ICF (fluid in RBC)
And ECF volume loss will result in what
An increased total plasma protein concentration
And ECF volume gain will result in what
A decreased total plasma protein (dilution)
What is normal hematocrit in men? What about women?
- 4 (men)
0. 35 (women)
Define the Gibbs-Donnan Effect
Due to an abundance of (-) charged proteins on the inside of the cell, there becomes an oncotic gradient favoring the movement of water into the cell as well as the movement of positive charges into the cell
How does the body counteract the Gibbs-Donnan Effect
With the NA/K ATPase pumps
Moves ions and also prevents excessive inward movement of water
As long as capillary blood pressure (hydrostatic pressure) exceeds plasma colloid osmotic pressure, what will happen
Filtration
When capillary blood pressure (hydrostatic pressure) falls below plasma colloid osmotic pressure, what happens
Absorption
What is plasma colloid osmotic pressure due to
Albumin
How does CHF lead to edema
Due to underfilling of vasculature (decreased MAP from a hypertrophied LV due to increased AoP) SNS kicks in and causes kidneys to retain Na and H2O which then increases capillary hyrodstatic pressure, making the problem worse and causing edema
Define:
Isotonic
Hypertonic
Hypotonic
Isotonic - equal movement of water into and out of cell
Hypertonic - shrinkage of cell, movement of water into ECF
Hypotonic - Lysis of cell, movement of water into ICF
Define crystalloids
Containing organic or inorganic salts dissolved in water
Will readily diffuse across capillary walls to affect ECF
Define colloids
Solution containing large proteins that don’t pass though the cell membranes or the capillaries. Stay in ECF and purely expand ECF volume without regard for electrolytes
Define hyponatremic dehydration
Loss of sodium is greater that loss of water in ECF
Increased serum sodium levels
Water shifts from ECF to ICF to establish an equilibrium
Will cause edema, brain cell swelling, muscle cramps, tachycardia, hypotension etc.
Define hypernatremic dehydration
Loss of water is greater than loss of Na in ECF
Serum Na in ECF is greater than ICF, causing a shift of water into the ECF
Edema and hypertension seen as well as hyperactive reflexes, decreased urine output, and increased thirst
Define volume contraction
A decrease in ECF which causes decreased blood volume and decreased blood pressure
Define volume expansion
Means an increase in ECF volume and thus pressure and edema
