Deck 11: Control of Ventilation

Question 1

The inhibitory neurons that switch off the inspiratory ramp arise from which of the following areas?
I.VRG
II.DRG
III.Pulmonary stretch receptors
IV.Pneumotaxic center

A) I, II, IV
B) III, IV
C) I, II, III, IV
D) II, III

Answer 1

III, IV

Question 2

Which of the following is (are) true of the Hering-Breuer reflex?
I.It results in an expiratory discharge pattern.
II.In adults it is activated only at small tidal volumes.
III.It has been suggested to be an important control mechanism in quiet breathing.
IV.It is important in regulating the respiratory rate and depth during moderate to strenuous exercise.

A) I, II
B) IV
C) I, II, III, IV
D) II, III

Answer 2

IV

Question 3

Which of the following conditions stimulate the chemoreceptors?
I.Hypercapnia
II.Acidemia
III.Hypoxia
IV.Alkalemia

A) I, II
B) III, IV
C) I, II, III
D) II, III, IV

Answer 3

I, II, III

Question 4

Which of the following conditions will elicit the strongest Hering-Breuer reflex?

A) Emphysema
B) Chronic bronchitis
C) Asthma
D) Pulmonary fibrosis

Question 5

Which of the following are considered effects of stimulation of the motor component of the vagovagal reflexes?
I.Bronchoconstriction
II.Laryngospasm
III.Coughing
IV.Bradycardia

A) I, III
B) I, II, III
C) I, III, IV
D) I, II, III, IV

Question 6

Stimulation of which of the following receptors explains the stimulation of ventilation after the splashing of cold water on the skin?

A) Stretch receptors
B) Peripheral proprioceptors
C) Irritating receptors
D) Cough receptors

Question 7

Transection of the brainstem between the pons and medulla results in which of the following respiratory patterns?

A) Apnea
B) Eupnea
C) Irregular breathing pattern
D) Periodic breathing

Question 8

Which of the following reflexes is (are) caused by stimulation of the irritant receptors?
I.Bronchoconstriction
II.Coughing
III.Bradypnea
IV.Narrowing of the glottis

A) I, II, IV
B) IV
C) I, II, III, IV
D) II, III

Question 9

Which of the following respiratory centers controls the length of inspiration?

A) DRG
B) VRG
C) Pneumotaxic
D) Apneustic

Question 10

Which of the following conditions produces the strongest stimulation of the J-receptors?

A) Pneumonia
B) Pneumothorax
C) Pleural effusion
D) Lung cancer

Question 11

When stimulated, the stretch receptors will have which of the following effects on respiration?

A) Produce apnea
B) Prolong inspiration
C) Prolong expiration
D) Stop further inspiration

Question 12

How much does minute ventilation increase for each 1 mm Hg rise in PaCO₂?

A) 1 to 2 L/min
B) 2 to 3 L/min
C) 4 to 5 L/min
D) 5 to 6 L/min

Question 13

What is the explanation for the minor importance of oxygen in controlling ventilation?

A) Oxygen molecules compete with CO₂ levels.
B) Oxygen molecules are fewer than CO₂ molecules.
C) Oxygen molecules do not cross the blood-brain barrier.
D) Oxygen molecules have no effect on the medullary chemoreceptors.

Question 14

Which of the following reflexes may be involved in periodic deep sighs and stimulating the first breaths of a newborn baby?

A) Hering-Breuer reflex
B) Head's reflex
C) Stretch reflex
D) Bötzinger reflex

Question 15

Which of the following statements are true of the DRG?
I.It consists mainly of inspiratory neurons.
II.It sends impulses to the phrenic and external intercostal motor nerves in the spinal cord.
III.It provides the main stimulus for inspiration.
IV.These neurons are involved in the Hering-Breuer and Head's reflexes.

A) I, II, III
B) III, IV
C) I, II, III, IV
D) II, III

Question 16

Which of the following statements describes apneusis?

A) Prolonged inspiratory gasps interrupted by occasional expirations
B) Prolonged inspiratory gasps interrupted by apnea
C) Prolonged inspiratory gasps interrupted by frequent expirations
D) Short inspiratory gasps interrupted by occasional expirations

Question 17

Which of the following procedures may elicit vagovagal reflexes?
I.Endotracheal intubation
II.Airway suctioning
III.Administration of aerosol therapy
IV.Bronchoscopy

A) I, II, III
B) IV
C) I, II, IV
D) II, III

Question 18

What is the clinical importance of the periodic deep sighs during quiet breathing?

A) Help prevent alveolar collapse or atelectasis
B) Maintain the normal breathing pattern
C) Help prevent apneustic breathing patterns
D) Promote coughing

Question 19

An acute increase in the PaCO₂ has an extremely powerful effect on ventilation.How long does it typically take for this effect to weaken?

A) 6 to 12 hours
B) 12 to 18 hours
C) 24 to 48 hours
D) 48 to 96 hours

Question 20

Which of the following effects are associated with stimulation of the J-receptors?
I.Rapid, shallow breathing
II.Sensation of dyspnea
III.Expiratory narrowing of the glottis
IV.Croup in infants

A) I, II, III
B) I, IV
C) I, II, III, IV
D) II, III

Question 21

What is the explanation for the lack of ventilatory stimulation when anemia and hypoxemia are present?

A) Extraction of oxygen in these two conditions remains stable.
B) The carotid bodies respond to decreased PO₂ rather than to an actual decrease in CaO₂.
C) The aortic bodies are insensitive to PO₂.
D) The carotid bodies respond only to CO₂ levels.

Question 22

What is the primary mechanism that drives ventilation in humans?

A) PCO₂
B) HCO₃^-
C) H⁺
D) pH

Question 23

What is considered the maximum level of PaO₂ on room air at maximal hyperventilation?

A) 100 mm Hg
B) 110 mm Hg
C) 120 mm Hg
D) 130 mm Hg

Question 24

Which of the following mechanisms explains ventilatory stimulation caused by hypoxemia in COPD patients with moderate hypoxemia?

A) Hypoxemia raises the peripheral chemoreceptors' sensitivity to [H⁺].
B) Hypoxemia stimulates central chemoreceptors.
C) Hypoxemia raises the central chemoreceptors' sensitivity to [H⁺].
D) Hypoxemia raises the peripheral chemoreceptors' sensitivity to [CO₂].

Question 25

Which of the following peripheral chemoreceptors has the greatest influence over the respiratory centers?

A) Aortic bodies
B) Carotid bodies
C) Femoral bodies
D) Brachial bodies

Question 26

Arterial hypoxemia does not stimulate ventilation until PO₂ reaches which level?

A) 60 mm Hg
B) 70 mm Hg
C) 80 mm Hg
D) 90 mm Hg

Question 27

Which of the following statements are true of CO₂ and cerebral blood flow?
I.Increased PCO₂ dilates cerebral vessels, raising cerebral blood flow.
II.Normal ICP is less than 10 mm Hg.
III.To sustain the cerebral blood flow, a cerebral perfusion pressure (CPP) of approximately 60 mm Hg must be maintained.
IV.Increased PCO₂ constricts cerebral vessels, decreasing cerebral blood flow.

A) II, III, IV
B) I, II, III, IV
C) II, IV
D) I, II, III

Question 28

Which of the following patterns describes Cheyne-Stokes breathing?

A) Tidal volume gradually increases and then gradually decreases to complete apnea without changes in respiratory rate. Then the tidal volume gradually increases again.
B) Respiratory rate and tidal volume gradually increase and then gradually decrease to complete apnea. Then the tidal volume and breathing frequency gradually increase again.
C) The respiratory rate gradually increases and then gradually decreases to complete apnea but tidal volume has essentially the same depth. Then the breathing frequency gradually increases again.
D) Tidal volume gradually decreases to complete apnea. Then the tidal volume gradually increases again, repeating the cycle.

Question 29

Why are COPD patients with chronic hypercapnia unable to hyperventilate to decrease their PaCO₂?

A) The central chemoreceptors respond only to O₂ concentration changes, not to changes in CO₂.
B) The central chemoreceptors are insensitive to acute or chronic changes in PaCO₂.
C) The central chemoreceptors respond to [H⁺], not the CO₂ molecule.
D) The central chemoreceptors do not respond to changes in hydrogen ion concentration or PaCO₂.

Question 30

What is the explanation for the suppression of the ventilatory stimulus present in subjects chronically exposed to high altitudes?

A) The exposure of central chemoreceptors to an alkaline environment
B) The exposure of central chemoreceptors to an acidic environment
C) The exposure of central chemoreceptors to a hypoxic environment
D) The exposure of central chemoreceptors to a hypercapnic environment

Question 31

How much reduction in cerebral blood flow is anticipated for every 1 mm Hg acute reduction in PaCO₂?

A) 1%
B) 2%
C) 3%
D) 4%

Question 32

Which of the following describes Biot's breathing?

A) Tidal volume gradually increases and then gradually decreases to complete apnea without changes in respiratory rate. Then the tidal volume gradually increases again.
B) The respiratory rate and tidal volume gradually increase and then gradually decrease to complete apnea. Then the tidal volume and breathing frequency gradually increase again.
C) The respiratory rate gradually increases and then gradually decreases to complete apnea but tidal volume has essentially the same depth. Then the breathing frequency gradually increases again.
D) Tidal volume gradually decreases to complete apnea. Then the tidal volume gradually increases again, repeating the cycle.

Question 33

Which of the following statement are true regarding the use of hyperventilation in the management of patients with TBI?
I.Hyperventilation is effective for only about 24 to 48 hours.
II.Hyperventilating patients with TBI to a PaCO₂ less than 30 mm Hg increases the danger of cerebral ischemia.
III.Every patient with TBI should be hyperventilated, at least during the first 24 hours.
IV.Hyperventilation therapy should be considered only for patients with high ICPs.

A) II, III, IV
B) I, II, III, IV
C) II, IV
D) I, II, IV

Question 34

Which of the following events are feasible explanations for the oxygen-associated hypercapnia that sometimes affects patients who have severe COPD?
I.Hypoxic stimulus removal
II.Worsening of relationships
III.As PaO₂ increases, the slow reduction in PaCO₂ induces hypoventilation.
IV.Shunt

A) II, III, IV
B) I, II, III, IV
C) II, IV
D) I, II

Question 35

Which of the following statements are true of the peripheral chemoreceptors?
I.They account for only 20% to 30% of the ventilatory response to hypercapnia.
II.Unlike the central chemoreceptors, the carotid bodies are directly exposed to arterial blood.
III.The initial ventilatory response to metabolic acidosis is fairly quick.
IV.They are the most important mechanisms that respond to hypercapnia.

A) II, III, IV
B) I, II, III, IV
C) II, IV
D) I, II, III