Chapter 32 Flashcards
Where are the neurons that activate the respiratory muscles rhythmically and subconsciously located?
The medulla, located within the brainstem
What drives the central pattern generator for respiratory ventilation?
Central and peripheral chemoreceptors
What do the central and peripheral chemoreceptors detect?
PCO2, PO2, and pH
What else can modulate ventilation besides the central pattern generators in the brainstem?
Other receptors and higher brain centers
What brain center is responsible for, but not entirely necessary, for respiratory output?
The pons
What does the dorsal respiratory group do?
Processes sensory input and contains inspiratory neurons
What does the ventral respiratory group do?
Processes motor output and contains both inspiratory and expiratory neurons
RRNs = ?
Respiratory rhythm neurons
Do RRNs fire at the same or different time during inspiration and expiration?
Different RRNs fire at different times
What do the firing patterns of different RRNs depend on?
Membrane ion channels and synaptic inputs
How is the respiratory rhythm activity initially generated?
Through pacemaker properties and synaptic interactions
What are the 3 models of where the respiratory CPG (central pattern generator) originate from?
- Restricted-site model
- Distributed oscillator model
- Emergent property model
What do peripheral chemoreceptors react to?
Hypoxia (low PO2), hypercapnia (high PCO2), and decreased pH (acidosis)
Where are the peripheral chemoreceptors located?
Carotid and aortic bodies
What is the specific cell that acts as a chemoreceptor?
The glomus cell
What physiological effects do hypoxia, hypercapnia, and decreased pH cause?
Inhibit K+ channels, raise glomus cell intracellular Ca2+, and release neurotransmitters
What separates the central chemoreceptors in the medulla from arterial blood?
The blood brain barrier
Where are the central chemoreceptors in the medulla located?
The ventrolateral medulla and other brain nuclei
Which neurons are unusually pH sensitive?
Neurons of the medullary raphe and ventrolateral medulla
What accentuates the response to respiratory acidosis?
Hypoxia
What accentuates the response to hypoxia?
Respiratory acidosis
What (and where is it located) provides information about lung volume and irritants in the lung?
Stretch and chemical/irritant receptors in the airways and lung parenchyma
What are the specific types of the 3 receptors that provide information about stretch, and chemical/irritant information in the lung?
- Slowly adapting pulmonary stretch receptors (PSRs)
- Rapidly adapting pulmonary stretch (irritant) receptors
- C-fiber receptors
What are some voluntary behaviors controlled by higher brain centers that can control lung ventilation?
- Sighs or “augmented breaths”
- Yawning
- Coughing reflex
- Sneezing
