Control of Respiration Flashcards
(28 cards)
What are the two main types of ventilation?
Passive (quiet breathing) and Active (deep or forced breathing).
What are the main goals of respiratory control?
Maintain O₂ supply, remove CO₂, and maintain blood pH.
What defines resting tidal volume?
Quiet breathing at rest.
Where is the respiratory rhythm primarily generated?
In the medulla, especially the Pre-Bötzinger complex
What is the function of the Dorsal Respiratory Group (DRG)?
Sends inspiratory signals via the phrenic nerve to the diaphragm.
When is the Ventral Respiratory Group (VRG) active?
During forced breathing.
What does the apneustic center do?
Promotes and prolongs inspiration.
What is the function of the pneumotaxic center?
Inhibits inspiration—limits its duration (acts as a “brake”).
What are the two types of respiratory control?
Voluntary (from the cortex) and Involuntary (from the brainstem and chemoreceptors).
Which chemicals regulate breathing?
CO₂ (via H⁺), O₂, and H⁺ concentration (pH).
Where are central chemoreceptors located and what do they detect?
In the medulla; they detect pH changes in CSF caused by CO₂.
How does CO₂ affect breathing?
Increased CO₂ → increased H⁺ → increased ventilation rate and depth.
Where are peripheral chemoreceptors located?
In carotid bodies (detect O₂ & H⁺) and aortic bodies (detect O₂).
What happens if the brainstem is severed below the medulla?
Respiration ceases—no voluntary or involuntary control.
What is the normal blood pH range?
7.38–7.42.
What causes respiratory acidosis?
Hypoventilation → CO₂ retention (e.g., asthma, emphysema, opioids).
What causes metabolic acidosis?
H⁺ accumulation (e.g., lactic acidosis, ketones, diarrhea).
How is respiratory alkalosis caused and compensated?
By hyperventilation; compensated by reduced renal H⁺ and HCO₃⁻ excretion.
What is metabolic alkalosis?
Excess HCO₃⁻ or H⁺ loss (e.g., vomiting); compensated by hypoventilation.
During exercise, what primarily stimulates breathing?
Neurogenic mechanisms and rising muscle temperature.
Does arterial PO₂ or PCO₂ change significantly during exercise?
No, they remain near normal due to matched increase in ventilation.
What happens to ventilation at high altitudes?
PO₂ drops → hypoxic hypoxia → ventilation increases (can lead to altitude sickness).
What is hypoxic hypoxia?
Low arterial PO₂ (e.g., high altitude, suffocation).
What is anaemic hypoxia?
Normal PO₂ but low O₂-carrying capacity (e.g., anemia, CO poisoning).
