PSIO202 Exam 2 Lecture 14 Flashcards
Even though respiratory muscles are skeletal muscles, they are under both —— and —— control.
automatic and voluntary
Where is the automatic control of respiratory muscles controlled from?
inspiratory and expiratory neurons in the medulla of the brainstem
Where is the voluntary control of respiratory muscles controlled from?
regions of the cortex
Resting breathing is ——–.
rhythmic
How is the rhythm of breathing controlled?
by pacemaker like neurons in the medulla
What activates inspiratory motorneurons? What does their activation cause?
pacemaker neurons, inspiratory motorneurons synapse onto respiratory muscles
What activates expiratory motorneurons?
respiration increases (with exertion or to perform a respiratory task)
Where are the neurons that control inspiratory muscles?
dorsal respiratory group (DRG)
Where are the neurons that control expiratory muscles?
ventral respiratory group (VRG)
Neurons in the DRG and VRG are…
pre-motor neurons
What do premotor neurons synapse onto? What is eventually innervated?
synapse onto motoneurons that innervate respiratory muscles
What are the three kinds of specialized receptors?
pulmonary stretch receptors, central chemoreceptors, and peripheral chemoreceptors
Where are pulmonary stretch receptors located?
smooth muscle lining the large airways, bronchi, and bronchioles
How do the pulmonary stretch receptors get their info up to the brainstem?
when the lungs inflate, the receptors are stretched, they respond to the rate of change of lung stretch on the afferent pathway via Vagus nerve (CN X)
Where are the peripheral chemoreceptors located?
aortic bodies in the aortic arch, and carotid bodies in the carotid sinus
What do peripheral chemoreceptors respond to?
primarily low oxygen in the arterial blood
little bit of response to H+ concentration and CO2
How is information from the peripheral chemoreceptors carried back to the control center? What is the control center for these receptors?
info from aortic bodies carried by CNX - vagus
info from carotid bodies carried by CNIX - glossopharyngeal
carried to the medulla
Where are the central chemoreceptors located?
adjacent to the respiratory control centers in the medulla
What are the principle roles of the central chemoreceptors?
CO2 sensitive by responding to increase in H+ in the CSF
How do central chemoreceptors work? Where do the H+ come from?
CO2 in the blood crosses the BBB, enters the CSF and combines with water to form carbonic acid, which breaks down into bicarbonate and H+. Those H+ ions are sensed and indicate an increase in CO2. The central chemoreceptors sense the H+.
Are the central or peripheral chemoreceptors faster?
peripheral (they don’t have to wait for crossing the BBB and an entire reaction to take place first)
How does information get from central chemoreceptors to the medulla?
They are right next to it, so it is basically already there.
What is the general pathway from low O2/high CO2 all the way to increasing ventilation?
change in O2 or H+ activates peripheral or central chemoreceptors, info is carried to the medulla/is already there for central receptors, medulla processes in DSG and VSG and send signals out on inspiratory (DSG) and expiratory (VSG) motoneurons, which innervate the respiratory muscles
