Week 6 Regulation of Respiration

Question 1

The three major groups of neurons located in the brainstem are:

Answer 1

Dorsal respiratory
Ventral respiratory
Pneumotaxic center

Question 2

___________ respiratory plays most fundamental role in control of breathing

Answer 2

Dorsal

Question 3

Motor signal transmitted from the DRG to the diaphragm IS/ IS NOT an instantaneous action potential burst

Answer 3

IS NOT

Question 4

The advantage of the ______ signal is that it causes a steady increase in inspiratory volume

Answer 4

ramp

Question 5

Two ways the ‘Ramp’ is controlled:

Answer 5

Control of the rate of ramp signal increases
-Ramp signal increases more rapidly during activity
-Lungs fill more rapidly
Control of limiting point at which ramp ceases
-Earlier the ramp ceases; the shorter the inspiration duration
-This also shortens the duration of expiration
-Frequency of respiration increases

Question 6

The VRG functions ________ from DRG

Answer 6

differently
VRG inactive during normal quiet respiration
VRG does not appear to participate in basic rhythmic oscillation which controls respiration
VRG contributes to respiratory drive to increase pulmonary ventilation
VRG stimulates abdominal muscles to assist in forced exhalation

Question 7

The Hering-Breuer Reflex is a

Answer 7

A protective feed-back reflex which limits the over- inflation of lungs

Question 8

Stretch receptors, that are located in muscular portions of bronchi & bronchioles and deal with the Hering-Breuer Reflex, transmit signals via the

Answer 8

the vagus nerve (X) to the DRG when lung is overstretched (TV > 1.5L)
-Feedback response switches off the inspiratory ramp & stops further inflation
• This reflex also increases the rate of respiration

Question 9

The DRG controls

Answer 9

inspiration & respiratory rhythm

Question 10

DRG receives signals from three sources:

Answer 10

Peripheral chemoreceptors
Baroreceptors
Lung receptors

Question 11

The VRG is normally at ______ but when there is an increased metabolic need it is ______

Answer 11

rest

activated

Question 12

Excess __________ or hydrogen ions in blood act________ on the respiratory center to increase strength of both inspiratory & expiratory motor signals

Answer 12

Carbon Dioxide
directly

CO2 is the driver
O2 is the backup driver

Question 13

[H]+ ions do not easily cross the _____

Answer 13

BBB

Question 14

______ is highly permeable to blood-brain barrier so blood & brain concentrations are equal

Answer 14

CO2

CO2 drives respiration

Question 15

Changes in blood CO2 concentration has potent _______ effect on controlling respiration drive but a weak _______ effect after a few days of adaptation

Answer 15

acute

chronic

Question 16

COPD pts have a blunted response to __________

Answer 16

increased CO2

Question 17

Blood oxygen levels below _________are sensed by peripheral chemoreceptors

Answer 17

PO2 of 70mmHg

Question 18

Chemoreceptors located mostly in

Answer 18

carotid and aortic bodies
• Carotid bodies
– Bifurcations in common carotid
– Afferent nerve fibers pass via CN IX to act on DRG
• Aortic bodies – Aortic arch
– CN X to DRG

Question 19

The curves are displaced to _____ at higher pH and _____ with lower pH

Answer 19

right

left

Question 20

What 3 conditions will increase drive for respiration?

Answer 20

High CO2, Low O2, Low pH

Question 21

A Low pH will

Answer 21

increase ventilatory drive

Question 22

A High CO2 will

Answer 22

increase ventilatory drive

Question 23

A Low O2 will

Answer 23

increase ventilatory drive

Question 24

What causes increases in ventilation during exercise?

Answer 24

Multiple factors involved in this ventilation change
• Brain transmits collateral impulses to brainstem while transmitting motor impulses to contracting muscles, VRG
• During exercise the body movements of joint & muscle proprioceptors transmit excitory impulses to respiratory center
• Hypoxia in muscles during exercise elicits afferent nerve signals to excite respiration center
• The Pco2 and Po2 changes caused by exercising muscles stimulate respiration

Question 25

The potential for C-S breathing is present in ______

Answer 25

everyone