Final Exam - Neural Control of Breathing Flashcards
What does a loud cough equate to lung function?
Loud cough = 2 L moving in and out of the lungs
Where is the primary controller of breathing located in the brain?
Medulla
What is the mesencephalon?
Midbrain
What are the chemosensors looking at in the blood related to breathing?
pCO2, pO2, pH ([H+])
Where are the peripheral chemoreceptors?
- Carotid bodies
- Aortic bodies
Central chemoreceptors primarily look at ____ for regulation of breathing?
[H+] in the CSF
What acids cause a delayed and immediate reaction by central chemoreceptors?
- Non-volatile acids have a harder time crossing the BBB (ionized) which causes a delay in activation of the central chemoreceptors
- CO2, a volatile acid, cross the BBB freely. Changes in CO2 levels cause an almost immediate response by central chemoreceptors
What happens during planned excercise to maintain a normal pH?
The higher orders of thinking (cerebral cortex) tell the brainstem to increase ventilation to the exact degree needed to maintain normal blood gases - sensors aren’t really needed for this scenario
What has the strongest effect on ventilation?
- [H+]
- paCO2
- pO2
How does the body respond to increases in metabolism?
- Vt increases
- RR increases
What is more effective at manipulating blood gasses, RR or Vt?
Vt
Increasing RR alone increases amount of deadspace ventilation
When would you want to use low Vt and higher RR during a case?
If the patient has RH failure - low volumes reduce PVR and RH strain
How does the body initiate an increase in Vt via nerves?
- Impulse strength is increased and sent via A⍺ fibers to respiratory skeletal muscles
- Once all motor units are recruited, the rate of impulse firing is then increased
How is RR changed by neural impulses?
RR is goverened by time in between impulses sent, the more time in between signals, the lower the RR
Which nerves are harder to block with regional anesthesia?
A⍺ - large myelinated nerves harder to block
If motor funtion is lost you can be almost certain that sensation is blocked because sensory pain fibers are smaller (Aδ and C fibers)
What 3 neural reflexes influence the respiratory cycle?
- Arterial chemoreceptors
- Central chemoreceptors
- Baroreceptors
Where are irritant receptors located?
How do they influence breathing?
- Lungs and Airways
- Irritants stimulate irritant receptors that are sent to the brainstem via the vagus nerve
What prevents overinflation of the lung during inspiration?
Stretch receptors located in the lungs that feedback to the brainstem
What nuclei in the medulla are involved in inspiratory control of breathing?
Dorsal respiratory group (DRG)
Ventral respiratory group (VRG)
Where do motor signals cross over?
Desuccation of the pyramids in the medulla
What is reciprocal inhibition?
- Activation of the inspiratory or expiratory centers in the brain inhibits the other
- Ex: the start of inspiration inhibits the expiratory centers
What controls the activity of the DRG/VRG?
Pontine Respiratory Group - “Apneustic Center”
There is no more neural control of breathing above this level
What are the 2 portions of the VRG?
Rostral (beak) and Caudal (tail) VRG
What is 3?
Where is it feeding into?
Vagus nerve (CN X) - feeds information into the medulla
