B4.051 Prework 2 Regulation of Ventilation

Question 1

what initiates inspiration

Answer 1

pacemaker cells in the respiratory center in the medulla spontaneously fire

Question 2

what determines resp rate

Answer 2

rate of firing of the resp center

Question 3

what determines tidal volume

Answer 3

intensity of firing of resp center

Question 4

describe the negative feedback loop of respiration regulation

Answer 4

central controller stimulated effectors
effectors act on receptors
receptors transmit to central controller

Question 5

what receptors act to regulate the resp muscles and airways

Answer 5

proprioreceptors
central chemoreceptors
peripheral chemoreceptors
lung receptors

Question 6

what is the central chemoreceptor sensitive to

Answer 6

CO2 levels
CO2 can cross blood brain barrier
H+ cannot cross blood brain barrier

Question 7

where are central chemoreceptors

Answer 7

brain ISf

Question 8

where are peripheral chemoreceptors

Answer 8

carotid bodies near arterial baroreceptor in carotid sinus

aortic bodies near aortic arch

Question 9

why are peripheral chemoreceptors distinct?

Answer 9

blood flow is tremendously high
oxygen needs are supplied entirely by dissolved O2 in blood due to high flow
cells of peripheral chemoreceptors are activated by decreased PO2 in arterial blood, not O2 content

Question 10

what are peripheral chemoreceptors sensitive to

Answer 10

decreased PaO2
increased PaCO2
decreased pH

Question 11

how do peripheral chemoreceptors exert action?

Answer 11

type I cells contain catecholamines
when exposed to hypoxia, release catecholamines
stimulate cuplike endings of the carotid sinus nerve fibers in the glossopharyngeal nerve

Question 12

only chemoreceptors that respond to PO2

Answer 12

peripheral

Question 13

is O2 or CO2 more sensitive to changes in ventilation

Answer 13

CO2

change in CO2 is what increased your urgency to breathe when holding breath