Week 2 Flashcards
Difference between serum and plasma
Serum - Liquid blood without clotting factors, used for liver function tests and kidneys
Plasma - Liquid portion including clotting factors contains CF, fibronogen
Lipaemic
Milky blood sample due to high lipid content
What causes a disruption of h20 homeostasis?
Dehydration, water intoxication, oedema (excess water in Ec compartment)
ABG
Arterial blood gas analysis
Hyperchloremic acidosis
Low bicarbonate high Cl-
May cause: Respiratory issues, mixed acid-base disorder, renal disease
Why is serum Na+ higher than K+?
NA+ EC, K+ IC, serum mainly reflects EC content
If one is too high or low, can cause disorder, important to maintain
How does penicillin salt cause hyponataraemia?
H - Low serum Na+ levels, Penicillin gives large amounts of Na+
Kidney secrets to maintain balance but this causes osmotic dieresis causing excess Na+ loss
What ketone most likely to cause a large osmolar gap in DKA?
b-hydroxybutyrate… most stable and most energy efficient
Causes largest osmolar gap due to high RFM and most abundant…
Why alcohol intoxication cause mixed base disturbance
Ketones produced affect pH levels, causes dec in pH and inc C02 levels
What species contribute to plasma osmolality?
Sodium (Na+), potassium (K+), chloride (Cl−), glucose, and urea.
How do osmoreceptors and baroreceptors regulate water balance?
Osmoreceptors trigger thirst and ADH release.
Baroreceptors monitor blood volume and adjust heart rate.
What is the osmolar gap, and why is it significant?
The difference between measured and calculated osmolality; a high gap (>10) suggests unmeasured solutes like ethanol, methanol, or ketoacids.
What are the major sodium homeostasis mechanisms?
Renin-angiotensin-aldosterone system – promotes Na+ reabsorption.
Glomerular filtration rate (GFR) – controls Na+ excretion.
Atrial natriuretic peptide (ANP) – promotes Na+ loss.
Dopamine – stimulates Na+ excretion.
What factors affect potassium homeostasis?
Acidosis shifts K+ out of cells.
Alkalosis & insulin shift K+ into cells.
Aldosterone promotes K+ excretion.
What are common disorders of sodium balance?
Hyponatremia: Excess water, ADH issues, renal disease.
Hypernatremia: Water loss (sweating, diarrhea), steroid excess.
What causes hypokalaemia and hyperkalaemia?
Hypokalaemia: Insulin use, diuretics, acid-base disturbances.
Hyperkalaemia: Acidosis, renal failure, tissue breakdown.
What are causes of chloride imbalances?
Hypochloraemia: Vomiting, cystic fibrosis.
Hyperchloraemia: Dehydration, chloride salt intake.
How are electrolytes measured in the lab?
ISE - Ion selective elctrodes
What is the significance of the renin-angiotensin-aldosterone system?
It regulates blood pressure and sodium balance by promoting Na+ and water retention and K+ excretion in the kidneys.
How does dehydration affect laboratory values?
Increased serum urea, creatinine, sodium, and osmolality
What are causes of pseudohyponatraemia?
High lipid or protein levels (e.g., multiple myeloma, hypercholesterolemia).
Measured Na+ appears lower due to reduced plasma water content.
What happens in respiratory alkalosis due to hyperventilation?
Increased blood pH (>7.45).
Low pCO₂ (<4.6 kPa).
Renal loss of bicarbonate (HCO₃⁻) and Na+, leading to hyperchloremia.
What causes hypernatraemia?
Excessive water loss (sweating, diarrhea, diabetes insipidus).
Steroid excess (Cushing’s or Conn’s syndrome).
High salt intake.
What are key indicators of acute kidney injury
Increased serum creatinine.
Elevated urea levels.
Reduced urine output.
Amphoteric substance
A substance that acts as both a base and an acid
Le Châtelier’s Principle
a system at equilibrium shifts to oppose changes in concentration, pressure, or temperature
What is the main source of H+ in the body?
CO2
How is CO2 transported in the blood?
As bicarbonate (HCO3−) (~70%)
Bound to hemoglobin (HbCO2) (~20%)
Dissolved in plasma (~10%)
How do the lungs help regulate pH?
exhaling CO2, reducing carbonic acid and increasing pH.
How do the kidneys help regulate pH?
By excreting H+ as ammonium (NH4+) and dihydrogen phosphate (H2PO4−) and reabsorbing bicarbonate.
What does a low anion gap suggest?
Hypoalbuminemia or multiple myeloma
types of acid-base disturbances
Metabolic acidosis – low pH, low HCO3−
Metabolic alkalosis – high pH, high HCO3−
Respiratory acidosis – low pH, high pCO2
Respiratory alkalosis – high pH, low pCO2
What causes metabolic acidosis?
Increased acid production (DKA, lactic acidosis)
Loss of bicarbonate (diarrhea)
Renal failure (impaired acid excretion)
What causes metabolic alkalosis?
Loss of H+ (vomiting, diuretics)
Excess bicarbonate intake
Hyperaldosteronism (increased Na+ retention, H+ loss)
What causes respiratory acidosis?
CO2 retention due to:
Hypoventilation (COPD, sedatives, airway obstruction).
What causes respiratory alkalosis?
Excessive CO2 loss due to:
Hyperventilation (panic attack, altitude, aspirin toxicity).
How does alcohol poisoning cause a mixed acid-base disorder?
Metabolic acidosis (due to lactic acid or ketoacids).
Respiratory alkalosis (due to hyperventilation).
What happens in aspirin (salicylate) overdose?
Respiratory alkalosis (early hyperventilation).
Metabolic acidosis (later accumulation of acids)
