IX: Control of Respiration Flashcards
Are pulmonary stretch receptors the only mechanical reflexes that can alter/modify breathing patterns?
No, there are actually several other mechanical reflexes that can alter breathing pattern by changing the timing, volume, and spacing of breathing. Ex: tickling sensation in throat can induce cough, blow to abdomen may halt breathing for a second, pulmonary emboli induce different patterns, motions of limbs during exercise contribute to increased breathing frequency and tidal volume, etc.
Where are chemoreceptors located (peripherally and centrally)?
- peripherally: aortic and carotid bodies, perfused w/ arterial blood
- centrally: ventrolateral surface of medulla, perfused w/ CSF
What do arterial (peripheral) chemoreceptors respond to?
primarily low levels of oxygen in the blood (but secondarily to low levels of CO2)
Are there venous chemoreceptors in the body? What about airway chemoreceptors?
no, there are none!
What do central chemoreceptors respond to?
exclusively to small changes in pH of CSF directly (or PaCO2 indirectly)
Are there any central chemoreceptors for oxygen? Explain the implications.
There are NOT central chemoreceptors for oxygen. Therefore, we are dependent on peripheral chemoreceptors to stimulate our automatic breathing in cases of hypoxia.
When is there a reflex increase in ventilation in terms of PaO2?
There is ONLY a reflex response to oxygen when it falls below 70 mmHg. However, the ventilatory response to hypoxia is enhanced by coincident increases in PaCO2.
Clinically defined as the cessation of breathing for at least 10 seconds.
apneic episode
What are the 2 types of sleep apnea?
1) Obstructive: upper airways are mechanically blocked by the tongue and rhythmical contractions of diaphragm are not enough to overcome blockade
2) Central: central respiratory controller is inoperative and expiratory phase is enhanced (no breathing is possible)
What happens during Cheyne-Stokes breathing?
Oscillation between hyperventilation and hypoventilation
