Chapter 8: Control of Ventilation Flashcards
What are the 3 parts of the Central controller system for respiration, what are each of their functions?
- Medullary respiratory center
- includes groups of cells called Pe-Botzinger complex –> respiratory rhythm generation
- dorsal respiratory group - inspiration
- ventral respiratory group - expiration (quiet during normal breathing) - Apneustic center
- lower pons - Pneumotaxic center
- upper pons
- fine-tuning of respiratory rhythm
In what part of the brain is inspiration and expiration controlled?
inspiration - dorsal respiratory group in the medullary respiratory center
expiration - ventral …
What are the 3 parts of the medullary respiratory center?
- Pre-boetzinger complex
- dorsal respiratory group
- ventral respiratory group
Where are the central chemoreceptors located and how do they work?
ventral surface of the medulla (brainstem)
respond to pH or CO2 changes and stimulate breathing accordingly
Where are the peripheral chemoreceptors located. What do they respond to?
- carotid bodies
- aortic bodies
glomus cells type 1 and type 2
pH, CO2, O2
Explain the repsonse of peripheral chemoreceptors to different levels of PaO2
sensitivity to changes highest at lower arterial PO2 mm Hg
very little response from these chemoreceptors until PaO2 is < 100 mm Hg
Compare the magnitude and speed of response to PaCO2 changes by the central and peripheral chemoreceptors
peripheral more rapid but central more important
List 4 lung receptors
- Pulmonary Stretch Receptors
- Irritant Receptors
- J Receptors
- Bronchial C Fibers
Where are pulmonary stretch receptors located, what do they respond to, what is their afferent nerve, and what is their effect?
airway smooth muscle
- respond to distensin of the lung –> send impulse via vagus nerve –> slows respiratory frequency
= Hering-Breuer inflation reflex
deflatin reflex - deflation of the lungs initiates inspiratory activity
Where are irritant receptors located, what are they stimulated by, what is their afferent nerve and what is their effect?
lie between airway epithelial cells
respond to noxious gases, cigarette smoke, dust, cold air
- vagus nerve
–> bronchoconstriction hyperpnea
Where ar the J receptors located, what is their afferent nerve, what are they stimulated by and what is their effect?
juxtacapillary - in the alveolar walls close to capillary
cause rapid, shallow breathing in response to edema
What are the bronchial C fibers, what supplies them and what is their effect?
respond to chemical irritants within the bronchial circulation –> rapid shallow breathing, bronchoconstriction, mucous secretion
How do PaO2 levels affect the chemoreceptors response to changes in PaCO2?
increases sensitivity to CO2 changes
What conditions/situations reduce the sensitivity of the ventilatory response to CO2 changes?
chronic hypercapnia
Which chemoreceptors are mainly responsible to respons to changes in pH. Under what circumstances can this shift, and what has to happen for this shift to be possible?
central