The integrated control of breathing

Question 1

What is the pH of arterial blood relative to?

Answer 1

→ Relative to the concentrations of bicarbonate ions and the partial pressure of CO2

Question 2

What regulates bicarbonate ions and in what time frame?

Answer 2

→The renal system in hours to days

Question 3

What regulates H+ ions and in what time frame?

Answer 3

→ The lungs in seconds to minutes

Question 4

How does respiratory acidosis occur?

Answer 4

→Hypoventilation because the respiratory system is not meeting the demands of the body
→pH changes because CO2 increases
→Ventilation is insufficient
→CO2 increases in the alveolar space and arterial blood (hypercapnia)
→Decrease in pH and acidosis
→ Activation of central chemoreceptors (increase ventilation rate)
→Kidneys decrease excretion of HCO3- to maintain normal pH

Question 5

What are the causes of hypoventilation?

Answer 5

→Asphyxia 
→Obstructive sleep apnoea 
→Increased airway resistance (COPD) 
→Drug overdose (inhibits brainstem) 
→Stroke 
→Neuromuscular problems

Question 6

How does respiratory alkalosis occur?

Answer 6

→Hyperventilation
→pH changes because less CO2
→Increase in pH and alkalosis
→Chemoreceptors slow down breathing rate so ventilation decreases
→kidneys respond in response by excreting more bicarbonate
→pH decreases.

Question 7

What are the two causes of hyperventilation?

Answer 7

→ Emotional response

→ Altitude

Question 8

How does altitude cause hyperventilation?

Answer 8

→  The pressure of the atmosphere decreases 
→ fraction of the gases stay  the same. 
→ The partial pressure of O2 decreases.
→ Less O2 going into the alveoli 
→ Ventilation increases 
→ CO2 decreases 
→ pH increases

Question 9

What causes metabolic acidosis?

Answer 9

→ Sepsis
→ Diabetic ketoacidosis
→ Renal failure
→ Diarrhoea

Question 10

How does sepsis cause hyperventilation?

Answer 10

→ Septic shock
→ Decreased O2 delivery to tissues 
→ Lactic acid gets produced in large amounts 
→ Decreased pH 
→ Tachypnoea occurs

Question 11

What causes metabolic alkalosis and how?

Answer 11

→ Diuretics
Changes to H+ and HCO3- reabsorption

→Vomiting
Loss of H+ in the stomach

→Antacids