Integrated control of ventilation

Question 1

What is a decrease in pH called?

Answer 1

Acidosis

Question 2

What is an increase in pH called?

Answer 2

Alkalosis

Question 3

Hypoventilation causes?

Answer 3

Increased CO2
Decreased pH therefore acidosis

Question 4

Hyperventilation causes?

Answer 4

Decreased CO2
Increased pH therefore alkalosis

Question 5

Equation linking pH, Pa CO2 and HCO3-

Answer 5

pH ∝(HCO3-)/
Pa CO2

Question 6

What is low pH with low (HCO3-) called?

Answer 6

Metabolic acidosis
Excessive metabolic acid production/increased excretion of HCO3-

Question 7

What is a high pH with high HCO3- called?

Answer 7

Metabolic alkalosis
reducedmetabolic acid production or reduced excretion of HCO3-

Question 8

What pathological states can cause metabolic acidosis?

Answer 8

either excessive acid production (sepsis, ketoacidosis)

or
excessive excretion of HCO3 (renal failure)

Diarrhoea

Question 9

What pathological states can cause metabolic alkalosis?

Answer 9

Excessive consumption of basic substances(antacid abuse)
Excessive excretion of acid from body
or excessive reabsorption of HCO3 (renal dysfunction).

Question 10

How does acidosis cause hyperkalemia?

Answer 10

During acidosis, there is a high H+ conc in the blood
As a compensatory mechanism intracellulae K+ moves out of cell in exchnage of uptake of H+ into cell
High extracellular K+

Acidosis means the extracellar H+ is higher
So H+ cannpt diffuse out of cell in exchnage for Na+

Question 11

How does alkalosis cause vasoconstriction?

Answer 11

Vascular smooth muscle is sensitive to changes in pH. (cerebral arteries are very sensitive)
CO2 acts a vasodilator
Therefore reductions in CO2 and H+ induce vasoconstriction of cerebral arteries

This can cause headache,light headedness, seizures and loss of consciousness