Electrolytes and Acid Base Flashcards
How much of an adults body weight is made up from Intracellular fluid?
40%
How much of an adults body weight is made up of extracellular fluid?
20%
What is extracellular fluid made up from?
Interstitial fluid and plasma
What is the primary reason for an electrolyte imbalance?
Diet
What is the definition of osmolality?
The distribution of solutes
What is the sodium potassium pump?
3 sodiums out of the cell for every 2 potassiums pumped into the cell
What does ADH do?
Secretion of ADH Causes resorption of water into the thick loop of henle
When may ADH be secreted?
When there is hyperosmolality (blood has a high concentration of salt, glucose and other substances)
What is the link between flow rate, Aldosterone and Potassium
High flow rate promotes potassium excretion
Low flow rate inhibits excretion
What is one of the affects of hypocholeraemia?
Low levels of chloride means it cannot help co-transport sodium
therefore potassium may also need to be excreted to help with the balance
Why does organic acidosis (ketones, lactate…) not promote kyperkalaemia?
They travel with H+ ions that move in and out of cells instead of Potassium
How may we measure electrolytes?
Using an Ion-Selective Electrode
Why may platelets clotting impact the results of electrolytes?
When platelets clot they release potassium so thrombocytosis may result in a higher serum K+
What can cause a sodium excess?
- Salt poisoning
- Administeration of hypertonic saline
- Decreased renal excretion
What causes normatraemia when the animal is dehydrated?
- Net loss of isotonic fluids
- Net retention of isotonic fluids
What causes hyponatraemia?
- Sodium loss is larger than the water loss
- Shift of water from the ICF to the ECF
What can cause hyperkalaemia?
- Shifting of K+ from the ICF to the ECF
- Increased total K+ due to decreased renal excretion
What are electrolytes?
Any substance that ionises when dissolved in water
e.g sodium, potassium, chloride
How is sodium regulated?
- Activation of the RAS system -> Angiotensin II -> Resorption of Na+, Cl-, and H2O in the collecting tubules
What effect does ANP have on sodium?
Sodium resorption in the distal nephron
What occurs when we have hyperosmality?
ADH is released, there is then increased resportion of H2O
What is the effect of inorganic acidosis on potassium?
may cause potassium to shift out of cells (hyperkalaemia in peripheral blood)
What is the effect of inorganic acidosis eg lactate or ketoacidosis on Potassium?
- Typically does not cause hyperkalaemia in peripheral blood
*
What can metabolic alkalosis cause in terms of potassium?
Mild hypokalaemia
How do you measure electrolytes
- Ion selective electrode
- it has a selective membrane taht only allows the ion of interest to enter
- the difference between the two electrodes is calculated and the ion concentration is then determined from this
Why may a sample not be accurate if there is a lot of lipids present in the LSE?
f lipid is present then electrolytes are not in the lipid fraction
BUT the machine will calculate as if all the plasma is in the aqueous
phase
What electrolyte is released when platelets clot?
When platelets clot, potassium is released, thrombocytosis therefore may result in higher serum K+
What is a hypertonic fluid?
Solute loss but with in an excess of water
What is a hypotonic fluid?
Water loss in excess of solute
What are the two ways hypernatraemia can be caused?
- H2O deficiency/ loss either renal or alimentary
- Na+ excess, could be due to salt poisioning, administration of hypertonic saline, or sodium bicarbonate
How does normotraemia occur when you are dehydrated?
- Net loss of isotonic fluids (alimentary, renal etc.)
- Net retention of isotonic fluids, due to oedema or transudate (Congestive heart failure, Hepatic cirrhosis, Nephrotic syndrome)
What is Hypernatraemia?
electrolyte imbalance consisting of an increase in serum sodium concentration
What can cause hyponatreamia?
- sodium deficit
- H2O excess
- Shift of Sodium from the ECF to the ICF and vice versa with water
What electrolye does chloride generally follow?
Generally will follow sodium
Its also affected by bicarbonate levels
What causes respiratory acidosis?
Increased levels of CO2
What causes metabolic acidosis?
Decreased levels of HCO3-
What causes respiratory alkalaemia?
decreased levels of CO2
What causes metabolic alkalaemia?
Increased levels of HCO3-
