Regulation of Respiration

Question 1

In the lung where would you find the most compliant alveoli?

Answer 1

base

Question 2

In the lung, where would you find the lowest arterial BLOOD pressure?

Answer 2

apex

Question 3

Optimal gas exchange occurs when ventilation is matched to perfusion

Answer 3

awesome

Question 4

Ventilation to perfusion ratio at the apex is

Answer 4

3.3

Question 5

ventilation to perfusion ratio at the base is

Answer 5

0.6

Question 6

V/Q ratio is highest at the apex, therefore,

Answer 6

the apex is “over ventilated and under perfused”

Question 7

PAO2 difference between apex and base

Answer 7

apex is 132 mmHg and base is 89 mmHg

Question 8

PACO2 difference between apex and base

Answer 8

apex is 28 mmHg and base is 42 mmHg

Question 9

difference in O2 in at apex and base

Answer 9

apex is 4 ml/min and base is 60 ml/min

Question 10

difference in CO2 out at apex and base

Answer 10

apex is 8 ml/min and base is 39 ml/min

Question 11

The apex has high PAO2 because

Answer 11

all ventilation and no perfusion so O2 is accumulating in the lung due to the high V/Q ratio and no perfusion is moving it away throughout the body

Question 12

Where in the lung would you find the lowest PACO2?

Answer 12

apex

Question 13

where in the lung would you find the lowest PAO2?

Answer 13

base

Question 14

where in the lung would you find the highest O2 uptake?

Answer 14

base

Question 15

blood leaving the lung has a PaO2 slightly less than PAO2

Answer 15

due to V/Q mismatch and shunting

Question 16

Control of Respiration

Answer 16

1. respiratory muscles require neural stimulation for contraction
2. brain establishes the breathing rhythm and force of contraction
3. changes in ventilation are assessed by feedback sensors which adjust neural output

Question 17

Medullary Respiratory Centers:
A. Regulate rhythmicity
B. Activate respiratory muscles
C. Three regulatory regions such as —>

Answer 17

1. DRG
2. VRG
3. Pre-Botzinger

Question 18

DRG

Answer 18

dorsal diaphragm
primary inspiratory neurons that synapse with motor neurons for inspiration

Question 19

VRG

Answer 19

insp and exp neurons active with forced breathing
maximal exercise (VICTORY)

Question 20

Pre-botzinger

Answer 20

respiratory rhythm generation (BPM)

Question 21

Pontine Respiratory Centers

Answer 21

A. Located in pons
B. two regulatory regions.
1. apneustic center
2. Pneumotaxic center

Question 22

Pontine Respiratory Centers:
1. Apneustic Center

Answer 22

prolongs inspiration by activating neurons in the pre-botzinger complex apneusis: sustained contraction

Question 23

Pontine Respiratory Centers:
2. pneumotaxic center

Answer 23

halts inspiration by sending inhibitory signals to the apneustic center and pre-botzinger complex

Question 24

Respiratory Control Centers:
Cortex

Answer 24

A. voluntary: modifies respiration for speech, yawning, coughing or breath holding
B. respiratory reflexes will over ride voluntary actions

Question 25

Respiratory Control Centers: Limbic system and hypothalamus

Answer 25

A. regulate emotional responses B. control breathing patterns during emotional states

Question 26

what region of brain is responsible for voluntary rates of ventilation?

Answer 26

cortex

Question 27

what region of brain is responsible for inspiration at rest?

Answer 27

dorsal respiratory group

Question 28

what region of brain is responsible for maximal ventilation

Answer 28

ventral respiratory group

Question 29

what region of brain is responsible for rate of ventilation?

Answer 29

pro-botzinger complex

Question 30

During quiet expiration,

Answer 30

there is no AP bc it is passive

Question 31

As ventilation increases until maximum ventilation with forced expiration,

Answer 31

the increased frequency of nerve signals creates bigger contractions

Question 32

Peripheral chemoreceptors: Arterial chemoreceptors detect changes in? location? regulate?

Answer 32

A. detect changes in PaO2, PaCO2, and pH B. primary sensitivity is to changes in PaO2 C. location: carotid artery and aortic arch D. do not regulate minute-to-minute changes E. emergency response for very low PaO2 levels F. do not respond to changes in O2 content

Question 33

Central Chemoreceptors: regulate? found? sensitive? permeable?

Answer 33

1. central chemoreceptors regulate minute-to-minute ventilation 2. found within the medulla near the VPG 3. very sensitive to PCO2 and H+ 4. BBB is permeable to CO2

Question 34

A major factor that quickly influences ventilation is: pH of arterial blood arterial PCO2 arterial PO2 arterial bicarbonate conc.

Answer 34

arterial PCO2

Question 35

Lung (pulmonary) receptors: 1. pulmonary stretch receptors found? prevents?

Answer 35

A. found within smooth muscle of lung airways B. stretching of lung induces activation of receptors which send inhibitory signals to the medullary centers C. negative feedback mechanism prevents over-inflation D. active when tidal volumes are high during max. exercise

Question 36

Lung (pulmonary) receptors: 2. irritant receptors found? mechanism?

Answer 36

a. found in airway epithelial cells b. noxious gas, duct, and cold air can activate receptors which leads to bronchoconstriction and rapid shallow breathing = protective mechanism limiting exposure c. irritant receptors may play a role in asthma d. activation of receptors can induce sneezing or coughing e. mechanical stimulation during intubation can lead to laryngeal spasm

Question 37

Lung (pulmonary) receptors: 3. pulmonary C fibers

Answer 37

a. near alveolar capillaries b. stimulated by interstitial edema which activates the J reflex that leads to laryngeal closure, apnea, followed by rapid shallow breathing c. may be responsible for rapid breathing seen in patients with pulmonary: emboli, edema, or pneumonia d. may also be responsible for feeling short of breath in patients with congestive heart failure

Question 38

Other Respiratory Receptors:

Answer 38

1. nose and nasal passages 2. upper airways: contain irritant receptors 3. joint and muscle receptors: give feedback to medullary centers and to increase ventilation

Question 39

the pneumotaxic center and stretch receptors will a. inhibit neurons in the apneustic center b. cause contraction of the diaphragm c. activate internal intercostal nerves d. cause respiratory arrest, then shallow breathing

Answer 39

a

Question 40

EXAM QUESTION what stimulates the highest rate of ventilation?

Answer 40

low O2 and high CO2

Question 41

what is the most important variable regulating ventilation?

Answer 41

PCO2 and usually maintained within 3 mmHg

Question 42

responses to changes in PO2 are greater with

Answer 42

hypercapnia

Question 43

responses to changes in PCO2 are greater with

Answer 43

hypocapnia

Question 44

Hyperventilation

Answer 44

decrease PCO2 and increase PO2 result in respiratory alkalosis low PCO2 is hypocapnia

Question 45

Hypoventilation

Answer 45

increase PCO2 and decrease PO2 result in respiratory acidosis high PCO2 = hypercapnia