Respiratory 5

Question 1

The ultimate goal of respiration is to maintain proper concentrations of what 3 things in the tissues?

Answer 1

O2, CO2 and H+

Question 2

Excess CO2 or H+activates respiratory centers to _____ alveolar ventilation.

Answer 2

increase

Question 3

Decreased O2 ____ alveolar ventilation

Answer 3

increases

Question 4

Decreased O2 increases alveolar ventilation. However, it does not directly impact central respiratory centers but instead acts on ______ that relay the signal to the central respiratory center.

Answer 4

peripheral chemoreceptors

Question 5

Involves descending input from the thalamus and cerebral cortex, can bypass the respiratory control centers in pons & medulla–Activated during talking, sneezing, singing, swallowing, coughing, defecation, anxiety, fear, etc.

Answer 5

Corticospinal tract

Question 6

Primarily controlled by changes in PCO2•Less sensitive to PO2 and H+•Pulmonary mechanical receptors–Activated by Respiratory Centers in the pons & medulla (ex. DRG and VRG)

Answer 6

Ventrolateral tract–

Question 7

What are the 2 Medullary Respiratory Centers:

Answer 7

–Dorsal Respiratory Group (DRG)

–Ventral Respiratory Group (VRG)

Question 8

What are the 2 Pontine Respiratory Groups

Answer 8

–Pneumotaxic Center

–Apneustic Center

Question 9

–Inspiratory Center
–Receives afferent input from Cranial Nerves IX (chemoreceptor) and X (chemoreceptor & mechanoreceptor)
–Provides excitatory inspiratory stimuli to phrenic motor neurons
–Sets the basic rhythm for breathing by setting the frequency of inspiration

Answer 9

Dorsal Respiratory Group: DRG

Question 10

What 2 CN give afferents to DRG?

Answer 10

CN IX and X

Question 11

Mostly involved in expiration–Primarily responsible for expiration•Expiration is normally a passive process, so these neurons are quiescent during normal breathing•Activated when forceful expiration is required

Answer 11

Ventral Respiratory Group: VRG

Question 12

_____ is normally a passive process, so these neurons are quiescent during normal breathing

Answer 12

Expiration

Question 13

The ________ are the only Receptors Sensitive to O2

Answer 13

Peripheral Chemoreceptors

Question 14

The Peripheral Chemoreceptors are stimulated by what things?

Answer 14

Decrease O2
INcrease in CO2
INcrease in H+

Question 15

What does O2 must fall to to cause a response by peripheral chemoreceptors?

Answer 15

60 mmHg

Question 16

The central chemoreceptors are stimulated by what?

Answer 16

Increase in H+ when CO2 is increased

Question 17

Afferent (sensory) information regulates the activity of the _________ via central and peripheral chemoreceptors and also mechanoreceptors

Answer 17

medullary inspiratory center (DRG)

Question 18

MOST important for minute-to-minute control of breathing•Located on ventral surface of medulla•Activation stimulates the DRG• are VERY sensitive to changes in pH of CSF

Answer 18

Central Chemoreceptors

Question 19

Activation of central chemoreceptors stimulate the _____

Answer 19

DRG

Question 20

Central Chemoreceptors are VERY sensitive to changes in ___ or _____

Answer 20

pH of CSF

Question 21

If AV increases, DRG recruits _____

Answer 21

VRG

Question 22

What causes DRG to recruit VRG?

Answer 22

AV increases

Question 23

Chemoreceptors in the CSF are only sensitive to changes in ____ concentration.

Answer 23

H+

Question 24

INcrease in H+ leads to ___ in AV

Answer 24

INcrease

Question 25

When CSF [H+] _______, there is an increase in respiratory volume and rate

Answer 25

increases

Question 26

_____ is permeable to the Blood Brain Barrier

Answer 26

CO2

Question 27

In the CSF, CO2 is converted to H+ and HCO3- via ______

Answer 27

Carbonic Anhydrase

Question 28

The H+ produced in the CSF activates the ______ which stimulates the DRG

Answer 28

Central Chemoreceptors

Question 29

The effect of a change in CO2 is _____ acutely

Answer 29

potent

Question 30

The effect of a change in CO2 is _____ chronically

Answer 30

diminished

Question 31

Central Chemoreceptors are most effective within _____ days after a change in central CO2.

Answer 31

1-2 days

Question 32

Why are central chemoreceptors most effective within 1-2 days after a change in central CO2?

Answer 32

–the kidneys will have begun to compensate, reabsorbing HCO3- –HCO3- has slowly diffused through the BBB and CSF barriers to buffer H+

Question 33

A danger for patients with chronic respiratory problems is that the kidney and buffer mechanisms compensate for the elevated PaCO2 (and H+) so that they no longer stimulate the medullary respiratory centers. Then the ______ -the only receptors that sample oxygen content—become critical for respiratory control.

Answer 33

peripheral chemoreceptors

Question 34

What 2 CN are associated with peripheral chemoreceptors?

Answer 34

CN IX and X

Question 35

where are the receptors for peripheral chemoreceptors located?

Answer 35

Carotid and aortic bodies

Question 36

______ are sensitive to low PaO2, high CO2, and low pH; larger response if both O2 is low and CO2 is high

Answer 36

Peripheral chemoreceptors

Question 37

What are the 3 conditions that peripheral chemoreceptors are sensitive to?

Answer 37

Low PaO2, High PaCO2, and Low pH

Question 38

What are the only receptors sensitive to O2 concentrations in the brainstem?

Answer 38

Peripheral chemoreceptors

Question 39

At PaO2 < _____mmHg, there is a LARGE increase in alveolar ventilation due to the ____ chemoreceptors?

Answer 39

60 mmHg; peripheral chemorectors

Question 40

Increases in PaCO2 increase the rate of firing of _____ to increase respiration

Answer 40

both aortic and carotid bodies

Question 41

Decreases in arterial pH increase the rate of _____

Answer 41

carotid bodies

Question 42

Hypoxemia enhances the response to _______

Answer 42

PaCO2.

Question 43

Are central or peripheral responses to changes in PaCO2 stronger?

Answer 43

Central

Question 44

Which chemoreceptors respond more quickly to changes in PaCO2?

Answer 44

Peripheral

Question 45

If PaCO2, does alveolar ventilation increase or decrease?

Answer 45

Increase

Question 46

Does sleep increase or decrease CO2?AV?

Answer 46

Increases both

Question 47

Do opioids increase or decrease CO2?AV?

Answer 47

Increase both

Question 48

Does DKA increase or decrease CO2?AV?

Answer 48

Decrease both

Question 49

Does DKA show an enhanced or decreased response to PaCO2?

Answer 49

Enhanced response

Question 50

Does sleep and opioids show an enhanced or decreased response to PaCO2?

Answer 50

Decreased response

Question 51

Most inhaled anesthetics cause respiratory depression by inhibiting the DRG and abolish/attenuate the response to ____ and _____

Answer 51

hypoxemia (decreased O2) and hypercarbia (increase CO2)

Question 52

Nitrous oxide actually _______ respiratory rate (tachypnea) and ________ tidal volume (via central stimulation) so there is minimal change in minute ventilation and PaCO2 levels.

Answer 52

increases respiratory rate (tachypnea) and decreases tidal volume (via central stimulation)

Question 53

Does nitrous oxide cause a large or small change in minute ventilation and PaCO2 levels?

Answer 53

Small change

Question 54

Hypoxic drive is ______ by nitrous oxide

Answer 54

decreased

Question 55

Nitrous oxide ______ pulmonary vascular resistance

Answer 55

increases