Integrated control of ventilation Flashcards
What are the 2 types of pH dysfunctions in the blood?
Acidosis - excessively low pH
Alkalosis - excessively high pH
What is respiratory acidosis?
Low pH accompanied by high PaCO2, hypoventilation is responsible for the increase in CO2 levels and decreased pH
What is respiratory alkalosis?
High pH accompanied by low PaCO2, hyperventilation is responsible for the decrease in CO2 levels and increased pH
What is metabolic acidosis?
Low pH accompanied by low [HCO3-], excessive metabolic acid production and/or increased excretion of HCO3-
What is metabolic alkalosis?
High pH accompanied by high [HCO3-], reduced metabolic acid production or reduced excretion of HCO3- is responsible for the increased pH
What is the body’s response to acidosis?
Increased activation of respiratory chemoreceptors and increased respiratory activity (compensatory hyperventilation). The resulting increase in CO2 removal from the blood/body increases blood pH until normal level are re-established via negative feedback.
What is the body’s response to alkalosis?
Decreased activation of respiratory chemoreceptors and decreased respiratory activity (compensatory hypoventilation). The resulting accumulation of CO2 within the blood/body decreases blood pH until normal level are re-established via negative feedback.
What is the cause of respiratory acidosis?
Pathological states involving chronic respiratory failure, hypoventilation, and accumulation of CO2, e.g. COPD
What is the cause of respiratory alkalosis?
Pathological states involving hyperventilation and excessive removal of CO2, e.g. anxiety- or altitude-induced hyperventilation
What is the cause of metabolic acidosis?
Pathological states involving either excessive acid production (sepsis, ketoacidosis) or excessive excretion of HCO3 (renal failure).
What is the cause of metabolic alkalosis?
Pathological states involving excessive consumption of basic substances (e.g. antacid abuse), excessive excretion of acid from the body (vomiting), deficient absorption of HCO3 from the gastrointestinal tract (chronic diarrhoea), or excessive reabsorption of HCO3 (renal dysfunction).
What is Acidosis-induced hyperkalemia?
Acidosis casues an increase in H+ ions in the blood meaning that less H+ will be pumped out of cells by the Na+ - H+ pump due to a decreased H+ conc gradient, this will cause there to be reduced action of the Na+ - K+ pump meaning that less K+ is being pumped into the cell causing more to accumilate in the blood.
How is potassium levels in the blood controlled?
The homeostasis of potassium levels within the blood is dependent on pH. Initial exchange of H+ and Na+ (hydrogen efflux, sodium influx), followed by Na+ and K+ exchange (sodium efflux, potassium influx) – the net effect is that potassium ions enter the cell in exchange for hydrogen ions leaving.
How does acidosis affect the homeostasis of K+ levels in the blood?
The initial step involving diffusion of H+ out of the cell in exchange for Na+, relies on the presence of a H+ concentration gradient – the concentration of H+ inside the cell must be greater than the concentration outside the cell. In the event acidosis, this process breaks down as pH falls, representing an increase in blood and extracellular [H+].
How does acidosis affect K+ levels in the blood as a whole?
uptake of K+ by cells is reduced in response to acidosis, leading to potassium accumulation within the extracellular fluid in blood.
