Lecture 30. Control of Respiration

Question 1

What is external respiration?

Answer 1

Exchange of oxygen and carbon dioxide between an organism and external environment

Question 2

What is breathing?

Answer 2

The act of muscle contraction/relaxation to move air in and out of the lung

Question 3

What is ventilation?

Answer 3

Movement air from outside to inside the body for exchange of gas between air in the lungs and blood in capillaries within the alveoli

Question 4

What are ventilation and breathing different aspects of?

Answer 4

External respiration

Question 5

What are the 3 aspects to the central control of breathing?

Answer 5

Voluntary/behavioural
Reflex/automatic
Emotional

Question 6

What generates inspiratory rhythm?

Answer 6

preBötzinger Complex

Question 7

What generates expiratory rhythm?

Answer 7

Parafacial respiratory group

Question 8

What coordinates the reflex/automatic control of breathing?

Answer 8

Ventral respiratory column

Question 9

Where does voluntary control of breathing originate from?

Answer 9

Motor complex

Question 10

When can voluntary control not be maintained?

Answer 10

When stimuli such as PCO2 or H⁺ become too intense

Question 11

When can emotional control of breathing still occur?

Answer 11

In sufferers of locked in syndrome

Question 12

What type of control does not occur in locked in syndrome?

Answer 12

Volitional control

Question 13

Where does emotional control of breathing arise?

Answer 13

Through corticospinal projections

Question 14

How is feedback patterned?

Answer 14

Via feedback mechanisms

Question 15

What does excess CO₂ lead to?

Answer 15

Acidification

Question 16

What is a potent regulator of breathing?

Answer 16

Hypercapnia

Question 17

What modulates breathing to a lesser degree than hypercapnia?

Answer 17

Hypoxia

Question 18

What do peripheral chemoreceptors detect?

Answer 18

Alterations in blood gases – predominantly oxygen

Question 19

Where are carotid bodies situated?

Answer 19

Close to bifurcation of common carotid arteries in the neck

Question 20

Where are aortic bodies situated?

Answer 20

Close to aortic arch

Question 21

What do central chemoreceptors detect?

Answer 21

Alterations in blood gases – predominantly carbon dioxide

Question 22

Where are central chemoreceptors mainly located?

Answer 22

In medulla oblongata but can be in other brain structures

Question 23

What do central chemoreceptors respond to?

Answer 23

Changes in cerebrospinal fluid

Question 24

What monitors lung inflation?

Answer 24

Slowly adapting pulmonary stretch receptors

Question 25

What monitor irritants?

Answer 25

Rapidly adapting pulmonary stretch receptors

Question 26

What are examples of monitoring irritants?

Answer 26

Promote cough in trachea and larynx
Promote sighing due to gradual collapse of lungs (atelectasis): ~5 minutes.

Question 27

Why do lungs require compliance?

Answer 27

So that they may inflate and deflate

Question 28

What is compliance?

Answer 28

Ability to expand lungs at any given change in (Pₜₚ)

Question 29

What are the two major determinants of lung compliance?

Answer 29

1. “Stretchability” of tissues
2. Surface tension within alveoli

Question 30

What lowers surface tension and increases compliance?

Answer 30

Pulmonary surfactant within alveoli

Question 31

When is pulmonary surfactant released and where?

Answer 31

Pulmonary surfactant is released from type II alveolar cells during sighing

Question 32

What do deficiencies in the foetal lung in premature babies result in?

Answer 32

Respiratory distress syndrome of the newborn

Question 33

What are protective reflexes?

Answer 33

Responses that protect the respiratory system from irritants

Question 34

What causes the cough reflex?

Answer 34

Due to receptors in epithelial cells of upper airway
Air speed of 960 km·h⁻¹

Question 35

What causes the sneeze reflex?

Answer 35

Due to receptors in epithelial cells of nose or pharynxAir speed of 160 km·h⁻¹