Lecture 8: Control of ventilation Flashcards
In the brain what are know as the respiratory centres
pons and the medulla
what spinal level is severd for breathing to cease
C3-5
respiratory centres can have their rhythm modulated, what factors do this
emotion
voluntary override
mechano-sensory input from the thorax
chemical composition of the blood
out of all factors that can have an effect on breathing rate what is the most significant
chemoreceptor input
what are the two types of chemoreceptors that you know of
central - medulla
peripheral - carotid and aortic bodies
the medulla is a central chemoreceptor, what does it respond directly to
directly to H+ which directly reflects the PCO2
the carotid and aortic bodies are peripheral chemoreceptors, what do they respond primarily to
primarily to plasma H+ and Po2 (less so to Pco2)
do central chemoreceptors monitor the Pco2 directly or indirectly in the CSF
indirectly
Dissolved co2 within the arterial blood can readily diffuse through the blood brain barrier into the CFS. what is it then converted to
carbonic acid H2CO3
the central chemoreceptor responds to what, H+ or CO2
H+ that is produced once the co2 has diffused across the BBB
what do peripheral chemoreceptors respond to, arterial Po2 or oxygen content
arterial Po2
If plasma pH falls (H+ increases) what will happen to ventilation
ventilation will be stimulated
if plasma pH increases (H+ falls) what will happen to ventilation
ventilation will be inhibited
what are the muscles used for inspiration
scalene
sternonucleoidmastoid
external intercostals
diaphragm
what are the muscles used for expiration
internal intercostals
abdominal muscles
