SM_157a: Control of Breathing Flashcards
Brain creates _______ and modifies that rhythm
Brain creates basic breathing rhythm and modifies that rhythm
(adjusts output to variety of muscles)
The motor pattern for breathing is generated by a _______
The motor pattern for breathing is generated by a central pattern generator
What is a central pattern generator?
A neuronal circuit within the CNS that can produce a patterned motor behavior such as breathing, locomotion, vocalization, or chewing without requiring phasic sensory feedback
Phasic sensory feedback may modify the motor output but is not essential for generting the basic motor pattern
What are the two large important regions in respiratory neuroanatomy?
- Ventral respiratory column
- Retrotrapezoid column
What is the function of the ventral respiratory column?
Generating a respiratory rhythm
What is the pre-Bötzinger complex?
Inspiratory rhythm generator
Where is the pre-Bötzinger complex found?
In ventral respiratory column, caudal to facial nucleus in ventral medulla
What is the retrotrapezoid nucleus?
Central chemoreceptor
Where is the retrotrapezoid nucleus found?
Ventral to facial nucleus, very near ventral surface of medulla
What are the basic sensory feedback mechanisms for breathing?
- Pulmonary mechanoreceptors
- Chemoreceptors
What are the types of pulmonary mechanoreceptors?
- Slowly adapting pulmonary stretch receptors (PSR or SAR)
- Rapidly adapting (irritant) pulmonary stretch receptors (RAR)
- C-fibers
What are the types of chemoreceptors?
- Peripheral chemoreceptors
- Central chemoreceptors
Where are the peripheral chemoreceptors located?
- Carotid bodies
- Aortic bodies
Where are the central chemoreceptors located?
Retrotrapezoid nucleus (potentially other places in CNS as well)
Compare slowly adapting pulmonary stretch receptors to rapidly adapting pulmonary stretch receptors
- Slowly adapting receptors adapt slowly and easily to respiratory lung inflation
- Rapidly adapting receptors require higher lung inflation to be activated and adapt firing rate even if a high lung inflation is maintained
Where are slowly adapting pulmonary stretch receptors located?
Smooth muscle of trachea and bronchi
What is the size and myelination status of slowly adapting pulmonary stretch receptors?
Large, myelinated fibers
What activates slowly adapting pulmonary stretch receptors?
- Lung inflation
- Bronchoconstriction
What does activation of slowly adapting pulmonary stretch receptors cause?
- Breuer-Hering reflex: facilitates expiration, terminates inspiration if VT is elevated (e.g. exercise), prolongs expiration (slows breathing)
- Abdominal (expiratory) muscle activation: airway obstruction -> increased FRC -> slowly adapting pulmonary stretch receptor activation -> decreased f and increased activation of expiratory muscles
- Bronchodilation: negative feedback loop
What is the effect of the Breuer-Hering reflex?
- Facilitates expiration
- Terminates inspiration if VT is elevated (e.g. exercise)
- Prolongs expiration (slows breathing)
(caused by activation of slowly adapting pulmonary stretch receptors)
What is the effect of abdominal (expiratory) muscle activation after activation of slowly adapting pulmonary stretch receptors?
Airway obstruction -> increased FRC -> slowly adapting pulmonary stretch receptor activation -> decreased f and increased activation of expiratory muscles
Bronchodilation after activation of slowly adapting pulmonary stretch receptors is a _______ feedback loop
Bronchodilation after activation of slowly adapting pulmonary stretch receptors is a negative feedback loop
What stimulates rapidly adapting pulmonary stretch receptors?
- Inhaled irritants
- Rapid large inflation
- Lung deflation
Where are rapidly adapting pulmonary stretch receptors located?
In airways from the nasopharynx to the bronchi
