Patho Final Flashcards
Concentration of the ICF, ECF, ISF, and plasma
ICF = 25L
ECF = 15L
ISF = 12L
Plasma = 3L
Major differences between ECF + ICF
- presence of cell proteins in ICF that cannot permeate the cell membrane to leave the cells
- unequal distribution of Na+ and K+ and their attendant ions as a result of the action of the NaK ATPase pump
What two factors maintain the body fluid balance?
- ECF volume
- helps give enough pressure for blood flow to tissues
- maintaining salt content in the body is necessary for long-term defense of ECF volume –> ALDOSTERONE
- lack of “pressure diuresis” keeps volume and pressure steady long term - ECF Na+ concentration/osmolarity
- helps prevent swelling or shrinking of cells
- 90% of regulating ECF osmolarity
- ADH + thirst add H2O to ECF, diluting the salt
osmolarity
measure of the concentration of individual solute particles dissolved in fluid
How can you change the osmolarity?
- Deficit of free water in ECF
- DEHYDRATION
- osmolarity = hypertonic - Excess of free water in ECF
- OVERHYDRATION
- osmolarity = hypotonic
Causes of hypertonicity, symptoms, effects
Causes:
- insufficient water intake
- excessive water loss
- diabetes insipidus
Symptoms/Effects:
- shrinking of brain neurons
confusion, irritability, delirium, convulsions, coma
- circulatory disturbances
lower plasma volume –> lower BP –> circulatory shock
- dry skin, sunken eyeballs, collapsed neck veins, dry tongue
Causes of hypotonicity, symptoms, effects
Causes:
- Renal failure –> cannot excrete dilute urine
- Drink water too quickly –> kidneys cannot respond fast enough
- SIADH –> too much ADH secretion –> water retained
Symptoms/Effects:
- WATER INTOXICATION –> swelling of brain cells
confusion, irritability, lethargy, headache, dizziness, vomiting, drowsiness, convulsions, coma, death
- weakness
- circulatory disturbances –> HTN (maybe) and edema
H2O Output - Insensible vs. Sensible Loss
Insensible
- NON-neural
- lungs
- non-sweating skin
Sensible
- Neural
- sweating, feces, urine excretion
What stimulates vasopressin? (normal conditions)
osmolarity rise
What produces vasopressin? What stores vasopressin?
produces: hypothalamus
stores: hypothalamus
hypothalamic osmoreceptors
vasopressin-secreting cells and thirst cells
osmolarity increase = vasopressin (ADH) secretion + thirst stimulated
osmolarity decrease = vasopressin (ADH) secretion decreased + thirst suppressed
What stimulates vasopressin? (emergency conditions)
drop in volume
- left atrial receptors monitor pressure of blood flowing through (reflects ECF volume) –> detects major reduction in arterial pressure –> stimulate vasopressin secretion + thirst
ex. HEMORRHAGES - angiotensin II –> stimulates vasopressin secretion + thirst when RAAS system activated to conserve Na+ (secondary)
Normal ABG values (pH, pO2, pCO2, O2 sat, HCO3-)
pH = 7.4 (7.37-7.44)
pO2 = 80-100
pCO2 = 36-44
O2 sat. = >95
HCO3- = 22-26
What pH values are deadly?
anything outside [6.8 - 8.0]
What is considered acidosis? Alkalosis?
Acidosis = below 7.35
Alkalosis = above 7.45
Small changes in pH can produce major disturbances including…
- dysfunction of enzymes –> work within narrow pH ranges
- electrolytes (Na+, K+, Cl-)
- hormones
What happens to the excitability of nerve and muscle cells with a fluctuation in pH?
- changes enzyme activity
- changes K+ levels in body (H+ and K+ compete for secretion into tubules)
Sources of H+ in the body
- carbonic acid formation –> from metabolically produced CO2
- inorganic nutrients produced during breakdown of nutrients
proteins in diet –> sulfuric + phosphoric acid - organic nutrients resulting from metabolism
fatty acids (fat), lactic acid (muscles primarily)
The body produces more (acids/bases) than (acids/bases).
ACIDS
- foods, metabolism of lipids + proteins, cell metabolism produces CO2