Electrolytes and ECG changes Flashcards
What are 3 main electrolytes?
Calcium, sodium, potassium
What is calcium balance is controlled by?
PTH (parathyroid hormone) and calcitonin
Influenced by Vitamin D and phosphate
What happens chemically when you have low calcium levels in your body?
Seceretion of PTH which then
>increases calcium absorption from GI tract and
>kidneys which promotes the reabsorption of Ca from the bones, then
>vitamin D is activated in the kidneys,
>promotes the movement of Ca from the bones and intestines into the blood
What is the role of calcium in the body?
Structural strength for bones & teeth
Stability of the nerve membrane, controls the permeability and excitability needed for nerve conduction
Muscle contractions (helps w end of contraction)
Metabolic process and enzyme reactions like BLOOD CLOTTING
What are causes for HYPOcalcemia?
hypoparathyroidism, decrease in PTH
Malabsorption
Renal failure ( vitamin D in kidneys to be absorbed)
- retention of phosphates, loss of calcium
- vitamin D is not activated
What are some results on HYPOcalcemia?
increases permeability and excitability of nerve membranes (muscle twitching, carpopedal spasms, hyperventilation syndrome)
severe–> laryngospasms and airway obstruction
heart: contractions are weak, conduction is delayed, arrhythmias develop, cardiac output drops
What is the difference between heart and skeletal muscles?
Skeletal- have an increased irritability of the nerves that control muscle fibres, calcium is stored IN the muscle!
Heart- NO nerves, contraction is directly affected by calcium levels, only available through calcium channels
What are causes of HYPERcalcemia?
Cancer
HYPERthyroidism
Immobility (disease stress on bones and demineralization
Increased intake of vitamin D
overdose of milk and antacids
What does HYPERcalcimenia result in?
muscle weakness
loss of tone
interefere with ADH, less absorption: polyuria (excessive urine)
severe: blood volume drops, renal function impaired, wastes accumulate (acidic) , cardiac arrest
heart: contractions increase strength and duration with dysrhythmias developing
bone: excess PTH, calcium intake, bone density and strength are affected
What is sodium balance controlled by?
by the kidney via aldosterone
What is the function of sodium?
- nerve impulse conduction
- muscle contraction
- extracellular fluid volume (affects osmotic pressure)
- force with which a solvent (fluid) passes through a membrane separating solutions of different concentrations
What are some causes of hyponatremia?
- excessive sweating, vomiting, diarrhea
- diuretic medications used with low fat diets
- hormonal imbalances
- chronic renal failure
- excessive water intake!
What are some results of hypnatremia?
- imparied nerve conduction, SLOWER
- fluid imbalances (fatigue, muscle cramps, abdo discomfort, cramps with nausea and vomitting)
- decreased osmotic pressure outside cells: fluid shift the cells: hypovolemic and drop in BP
- brain swelling, CNS effects, headaches, confusion, seizures
What are causes of HYPERnatremia?
- ingestion of large amounts of sodium
- disproportionate water intake
- insufficient antidiuretic hormone
- loss of thirst mechanism
- loss of thirst
- watery diarrhea
What are results of hypernaatremia?
weakness, agitation, increased thirst with dry rough mucous membranes
- decreased urinary output (ADH secretions)
- increased urinary output (if the cause is ADH insuffiency
