Chapter 1 Flashcards
Homeostasis
the body’s ability to maintain internal stability; relatively constant and favorable.
Physiology
a study of the normal function of cells, tissues, and organs in living organisms.
Pathophysiology
describes abnormal body functions, especially those mechanisms known to be altered by diseases.
Total body water (TBW)
- All of the water in the animal body
- Approximately 67-70% of body weight
- Mostly intracellular or extracellular fluid
Extracellular Fluid (ECF)
- All body fluid outside of cells.
- Comprises about 30% of TBW
- Includes interstitial fluid, blood plasma, & transcellular fluid.
Intracellular Fluid (ICF)
- All body fluid inside of cells.
* Comprises about 70% of TBW
Interstitial Fluid (ISF)
- Main component of extracellular fluid
- Solution that surrounds cells; found in interstitial spaces (tissue spaces)
- about 20% of TBW
Osmolarity
- The measure of solute concentration.
- number of osmoles (Osm) of solute per L of solution
- Osmolarity of most body fluids is about 300 mOsm/l
Osmolality
Osmoles per kilogram of solvent
Mole
unit of measurement to express amounts of chemical substance
- Avogadro’s constant=6.023 x 10^23
- mole of NaCl= 58.5g
Freezing Point Depression
describes the process in which adding a solute to a solvent decreases the freezing point of the solvent.
Acidosis
an increased acidity in the blood and other body tissue (i.e. an increased hydrogen ion concentration)
*pH falls below 7.35
Alkalosis
reduced hydrogen ion concentration of arterial blood plasma
*pH of blood exceeds 7.45
Hypernatremia
an electrolyte disturbance that is defined by an elevated sodium level in the blood.
*generally not caused by an excess of sodium, but rather by a deficit of free water in the body (Dehydration)
Hyponatremia
an electrolyte disturbance in which the sodium ion concentration in the serum is lower than normal.
Hyperkalemia
refers to the condition in which the concentration of the electrolyte potassium (K+) in the blood is elevated.
Hypokalemia
refers to the condition in which the concentration of potassium (K+) in the blood is low.
Hypercapnia
a condition where there is too much carbon dioxide in the blood.
Hypercarbia
another name of hypercapnia; too much carbon dioxide in the blood.
Azotemia
a medical condition characterized by abnormally high levels of nitrogen-containing compounds. (urea, creatinine, various body waste compounds, and other nitrogen-rich compounds in the blood)
*Insufficient filtering of blood by the kidneys.
Deciliter
10 deciliters in a liter; 100 ml in a deciliter
Blood Plasma
- Portion of extracellular fluid; fluid portion of blood.
- About 92% is water; most of the rest is protein.
- 7-9% of TBW
Transcellular Fluid
- Portion of extracellular fluid found within epithelial lined spaces.
- 1-3% TBW
- includes CSF, aqueous humor, secretions, tubular fluid, etc.
Dehydration
*Loss of water; expressed in percent body weight
(A) 5%= skin has doughy consistency
(B) 7%= loss of skin elasticity; eyeballs appear sunken; urine has high specific gravity
(C) 10-12%= involuntary muscle twitching & shock
(D) 15%= severe shock and a moribund state
Major Intracellular Solutes
- Potassium
- Phosphate
- Magnesium
Major Extracellular Solutes
- Sodium
- Chloride
- Bicarbonate
Importance of Ion Content
*Electrolyte depletion (K+ or Ca++)
Extreme weakness and abnormal cardiac function.
Importance of Ion Content
*Narrow range of pH
Most cellular biochemical reactions are dependent on a very narrow range of H+ concentration. Life may be threatened if the blood pH varies more than 0.3 unit.
- Normal pH=7.4
- pH=-log[H+]
Importance of Ion Content
*Deficiency of plasma HCO^3-
Severe metabolic acidosis
Importance of Ion Content
*Alteration in Na+ concentration of body fluids
has a serious effect on the hydration status of the animal; water follows Na+
More concentrated inside of outside of the cell?
- Na+
- K+
- Cl-
- Ca++
- Mg++
- Protein
- (Na+) Extracellular
- (K+) Intracellular
- (Cl-) Extracellular
- (Ca++) Extracellular
- (Mg++) Intracellular
- (Protein) Intracellular
Hypoosmolal states
Cause water to shift from the ECF to the ICF.
Hyperosmolar states
Casue water to move from the ICF to the ECF; usually casued by hypernatremia or hyperglycemia.
Hyperglycemia
High levels of glucose in the blood.
Measurement of volume of compartment by an indicator
Volume= Quantity of indicator added/ Concentration of indicator
**Subtract anything lost from the numerator.
Packed Cell Volume (PCV)
Percentage of whole blood that is occupied by red blood cells.
**Also termed Hematocrit (Hct)
What are the 4 ways to measure solute concentration?
- Mass/Volume
- Molecular Concentration/Volume
- Particle #/Volume
- Electrochemical reactivity/Volume
Average osmolarity of serum, and which ion is it most dependent on?
about 300 mOsm/L; Na+
How do you measure fluid compartment size?
Indicator dilution; Amount of indicator added/concentration of marker when completely diffused= volume of compartment
What indicator do you use to measure total body water?
What additional change must you account for when using the indicator dilution principle?
Deuterium Oxide (D2O)
You have to subtract any amount of indicator lost (urine).
Total D2O-amount lost/concentration of D2O after dilution= Total body water
What indicator do you use to measure blood plasma volume?
How do you use this measurement to find Total blood volume?
Evan’s Blue
Blood Volume= plasma volume x (100/(100-PCV))
How do you determine Interstitial fluid volume?
Difference between the volume of extracellular fluid and plasma
How do you determine extracellular fluid volume?
A substance called inulin is added in the extracellular fluid. Inulin is collected through the urine at different intervals and measured.
Volume=total inulin collected in urine/concentration of inulin in beginning
How do you determine Intracellular fluid volume?
Calculate the difference between total body water and extracellular fluid volume.
Hypotonic solution
causes a cell to swell
Hypertonic solution
causes a cell to shrink
