Fluid And Electrolytes Flashcards
What is the definition of an electrolyte?
A substance capable of dissociating into ions and which in a solution will conduct electrical current.
What is a solute?
The substance/compound that is dissolved in a solution
What is a solvent?
The liquid in which another substance is dissolved in to form a solution.
What percentage of the body weight is fluid in adults and in children?
60% in adults
80% in children
What percentage of water is intracellular and extracellular?
66% intracellular
33% extracellular
What 2 categories is extracellular divided into?
Intravascular and interstitial
How much total volume of fluid in the body is interstitial and intervascular?
25% interstitial 8% intervascular
What separates fluid spaces in the body?
Permeable and semi permeable membranes
Is diffusion an active or passive transport system?
Passive
What is the term for diffusion of water?
Osmosis
What is osmotic pressure?
The amount of pressure that would be required to prevent the movement of water across a gradient.
What determines osmotic pressure?
The amount of particles of solute on the more concentrated side.
*The greater the concentration of solutes the more “pull” there will be to draw water through the membrane and therefore greater pressure required to prevent that.
What is the term for moving substances against the concentration gradient?
Active transport
What are the 4 main ways the body loses fluid?
Urine, sweat, breathing, GI tract.
What is the basic daily minimum for fluid intake?
2500ml
Do infant need more or less fluid, and why?
More fluid intake is required because,
Larger surface area related to mass
increased metabolic rate
Kidneys are not as efficent
Smaller fluid reserve
What percentage of NaCl will stay in the intravascular space in fluid resuscitation?
33%
What area of the brain is responsible for control of antidiuretic hormone?
The pituitary
What does antidiuretic hormone (Vasopressin) do?
ADH is released from the pituitary and effects the kidney causing an increase water retention in the kidneys.
Effects on DCT and collecting ducts of kidney
Vasoconstriction
What are some clinical signs of volume depletion?
Poor skin tugor, dry mucus membranes, increased body temp, decreased blood pressure, tachycardia, skin colour.
Where does aldosterone come from?
The adrenal cortex
What does aldosterone do?
Increases the amount of sodium retained in kidneys
Particularly the distal nephron
What are some signs of volume depletion in children/infants?
Sunken eyes, sunken fontanel, low grade fever, altered mental status, limp tone
What is the physiologic role of electrolytes?
Transmission of electric current in a solution.
What is the main cation in the intracellular fluid?
Cation- Potassium
What is the main cation and anion in the extracellular fluid?
Cation - Sodium
Anion- Chloride
What are some signs of hypernatremia?
Extreme muscle irritability, dry mucus membranes, flushed skin, thirst
What are some signs of hyponatremia?
Lethargy, muscle weakness, decreased urinary output, mental confusion
What are the effects of hyperkalemia on cardiac tissue?
Peaked T-waves, flattening of P-waves, QRS widening, slowing of HR, heart blocks, weakening of cardiac contractility.
What are the effects of hypokalemia on cardiac tissue?
Cardiac excitability, tachycardia, ectopy
