Midterms 01. Electrolytes

• calcium

• potassium

may cause cardiac arrest

• calcium

• magnesium

electrolytes involved in blood coagulation

magnesium

is very important in diet

water

dissolves electrolytes

• sweat

• urine

water removes waste product through:

edema

water retention of 3L or >3L

arginine vasopressin deficiency

10-20L water excretion may lead to →

• sodium

• potassium

use of sweat for determination

equal

input and output should be

ion concentration within cells & in plasma

maintained by active transport processes & passive diffusion

active transport

requires energy or ATP

passive transport / diffusion

doesn’t require ATP

osmolality

physical property of a solution based on the concentration of solutes (millimoles) per kg of solvent (w/w)

osmolality

related to several changes in the properties of a solution relative to pure water

concentrated solution → thirst

increased osmolality = ??

diluted solution (water overload)

decreased osmolality = ??

275-295 mOsm/kg

osmolality normal value

• sodium

• chloride

• bicarbonate

92% osmolality composition

anion gap

difference between unmeasured anions & unmeasured cations

anion gap

used as an analyzer QC

diabetic ketoacidosis

anion gap is also used to monitor this condition

10-20 mmol/L

anion gap normal value

sodium

concentration depends on intake & excretion of water

sodium

major contributor of plasma osmolality

• serum

• heparin plasma

• 24 hr urine

• sweat (Policarpine merhod)

specimen used for determination of sodium

sodium

most abundant cation in the ECF (90%)

sodium

natrium

glass aluminum silicate

ion selective electrode for sodium

• aldosterone

• atrial natriuretic factor

hormones affecting sodium levels

aldosterone

secreted by adrenal cortex that promotes Na retention of K excretion

atrial natriuretic factor

endogenous anti hypersensitive agent secreted from cardiac atria

atrial natriuretic factor

block aldosterone & renin secretion

atrial natriuretic factor

inhibits Angiotensin II & Vasopressin

natriuresis

ANF inhibits Angiotensin II & Vasopressin

hypernatrimia

serum Na > 145 mmol/L

hypernatremia

caused by loss of water = gain of sodium

thirst

major defense against hyperosmolality & hypernatremia

hyponatremia

serum Na < 135 mmol/L