Electrolyte Balance Flashcards
():
Decreased sodium decreases (/)
Causes: Renal failure, Vomiting & Diarrhea, Diuretic use, Excessive fluids, Low ()
This can lead to cellular edema (esp. in brain—Hypervolemia)
Worse if sodium drops too fast (24-48 hrs)
Brainstem herniation, resp. arrest, death
Hypovolemic: potential () shock
Hyponatremia
ECF osmolarity
Aldosterone
circulatory
(/) usually refers only to () balance
() control fluid movements, provide minerals for excitability, secretory activity, and other functions
() () body by ingestion and metabolism
() are lost via (), feces, (), vomit
Electrolyte balance
salt
enter
perspiration
urine
():
Increased sodium increases ECF ()
Causes: Excessive fluid loss, Excessive sodium intake/() fluids
Cells lose fluid and become thirsty
Symptoms: Thirst,Twitching, Fluid retention/Edema, Confusion
Hypernatremia
osmolality
hypertonic
Regulation of NA balance:
Na+-water balance is linked to blood () and blood () control mechanisms
Changes in blood pressure or volume trigger () and () controls to regulate Na+ content
() plays biggest role in regulation of Na+ by kidneys
Causes Na reabsorption
(/,/)mechanism is main trigger for aldosterone release
pressure
volume
neural
hormonal
Aldosterone
Renin-angiotensin-aldosterone
()
Low () levels”
Affects cardiovascular/neuromuscular restingmembrane potentials
-Fluid loss due to vomiting, diarrhea, prolonged diuretic use (MOST COMMON)
-() is mostly intracellular (not much in ECF)
-Decreased levels in ECF increase Resting Membrane Potential (make more negative)
-()
-Nerves require more stimulus to fire
-Muscles become ()
-In heart, Na/K pump is affected
-Sodium & Calcium accumulate in cell; prolonging AP causing()
Hypokalemia
potassium
Potassium
Hyperpolarization
weakened
arrythmia
()
Excessively high () levels”
() failure, tissue destruction (burns, trauma, & flesh-eating bacteria)
Excessive K+ in ECF causes () (decrease RMP/more positive)
Cells are more easily excitable; ( & )
Over time, Na+ channels close and K+ channelopening
Cell becomes (); cannot respond to stimuli
Increase P-R interval, Widened QRS, Flattened P wave
Hyperkalemia
potassium
Renal
depolarization
Arrythmias & Fibrillation
refractory
Regulation of calcium and phosphate
99% of body’s () is found in bones as calcium phosphate salts
Calcium balance controlled by () hormone (PTH) and rarely deviates from normal limits
PTH promotes increase in blood calcium levels by targeting
-() intestine—increases calcium absorption
-()—increases calcium reabsorption
-()—osteoclasts break down matrix, releasing calcium and phosphate to blood
calcium
parathyroid
Small
Kidneys
Bones
Ca2+ in ECF is important for:
Blood ()
Cell membrane ()
() excitability: most important
clotting
permeability
Neuromuscular
():
“Low calcium levels”
Increases neuromuscular excitability
Normally Calcium inhibits sodium channels
Can lead to muscle ()
Hypocalcemia
tetany
():
Decreases neuromuscular excitability
Inhibits sodium channels
Muscle () & potential cardiac arrest
Hypercalcemia
weakness
Acid-Base Balance
() affects all functional proteins and biochemical reactions, so it is closely regulated by the body
Normal pH of body fluids: (-)
(): arterial pH >7.45
(): arterial pH <7.35
Most ()+is produced as a by-product of metabolism:
() acidfrom () respiration of glucose
() acidsand ketone bodies from fat metabolism
H+is liberated when CO2is converted to bicarbonate (HCO3– ) in blood
pH
7.35-7.45
Alkalosis
Acidosis
H
Lactic,anaerobic
Fatty
H+ regulation
(/) systems
Rapid, first line of defense
()
Brain stem () centers
Acts within 1–3 minutes
Increase movement of CO2 to lungs & increases () (expiration)
() mechanisms
Most potent, but require hours to days to effect pH changes
Chemical buffer
Bicarbonate
respiratory,exhalation
Renal
Bicarbonate buffer system:
Mostly provided by () Bicarbonate - ()
If strong acid is added, HCO3– ties up H+ and forms H2CO3
Converts strong acid to weak acid
pH decreases only slightly
HCO3–is closely regulated by ()
If strong base is added, H2CO3 donates H+
Ties up ()group
pH increases only slightly
Sodium
NaHCO3
kidneys
OH-
