Fluid And Electrolytes Flashcards
Dehydration (negative water imbalance)
Total body water: reduced
Osmolarity: hypertonic (elevated)
Fluid excess/ volume excess
Total body water: elevated
Osmolarity: isotonic (normal)
Hypotonic hydration (positive water balance, water intoxication)
Total body water: elevated
Osmolarity: hypotonic (reduced)
Lack of drinking water
Total body water: reduced
Osmolarity: hypertonic (up)
Form of fluid imbalance: dehydration
Severe blood loss
Total body water: reduced
Osmolarity: isotonic (no change)
Form of fluid imbalance: hypovolemia
Prolonged vomiting
Total body water: reduced
Osmolarity: isotonic (no change)
Form of fluid imbalance: volume depletion/ hypovolemia
Rapid overhydration
Total body water: elevated
Osmolarity: hypotonic (down)
Form of fluid imbalance: hypotonic hydration
ADH hyposecretion
Total body water: reduced
Osmolarity: hypertonic (up)
Form of fluid imbalance: dehydration
Too much i.v. saline
Total body water: elevated
Osmolarity: isotonic (no change)
Form of fluid imbalance: volume excess
Salts that ionize in water
e.g. NaCl—> Na++ C+
Electrolytes
Charged particles
- carry currents
- fluid balance of body
Ions
Contribution factors to RMP
- K+ out along its gradient
- Na+ in along its gradient
- active movement of 2k+ in 3Na+ by Na-K pump
Depolarization closer to threshold
If cell becomes more positive
Hyperpolarization further from threshold, harder to excite
If cells become more negative
Fluid deficiency volume depletion (hypovolemia)
Total body water: reduced
Osmolarity: isotonic (normal)
- Main cation of ICF
- Imbalance dangerous: [K+] ECF controls RMP
K+
-low blood K+
-K+ flows out of cells
-cells hyperpolarized= less excitable
(muscle weakness, irregular heartbeat)
Hypokalemia
-cells depolarized
-more excitable
(irregular heartbeat, muscle tingling)
e.g. kidney failure
hyperkalemia
Ca+ balance=
muscle, clotting, 2nd messenger systems
- decreased Na+ permeability of membrane
- less Na+ diffuses into cell
- cell more negative (hyperpolarized)
- inhibits nerve muscle firing
HYPERcalcemia (e.g. excess PTH)
- increased Na+ permeability
- more Na+ diffuses into cell
- cell more positive (depolarized)
- nerve and muscle cells overly excitable
- tetnany, seizures
HYPOcalcemia
- main cation of ECF
- since “water follow salt” main problem is swelling/shrinkage
Na+ balance
cerebral edema
hyponatremia
brain cells shrink
usually due to brain shrinkage
hypernatremia
- main cation of ECF
- most significant solute in determining total body water and water distribution across fluid compartments
Na+
- main cation of ICF
- most significant solute I determining intracellular osmolarity and cell volume
K+
used as 3rd messenger system
Ca2+
- released if osmolarity of ECF increases
- synthesizes aquaporins/more water rea scorned
- water conservation=concentrated water
ADH
- released if K+ increases & Na+ decreases in ECF
- Na+ conservation in kidneys; “water follows salt”
Aldosterone
