Respiratory Physiology 2

Question 1

What is Tidal Volume?

Answer 1

The volume of air breathed in and out with each breath.

Question 2

What is the Expiratory Reserve Volume?

Answer 2

The maximum volume of air that can be expelled from the lungs at the end of a normal respiration.

Question 3

What is the inspiratory reserve volume?

Answer 3

The maximum volume of air which can be inhaled at the end of a maximal expiration.

Question 4

What is the Residual Volume?

Answer 4

The volume of gas in the lungs at the end of a maximal expiration.

Question 5

What does Vital Capacity refer to?

Answer 5

Tidal volume, inspiratory reserve volume and expiratory reserve volume together.

Question 6

What is meant by Total Lung Capacity?

Answer 6

Vital capacity plus the residual volume.

Question 7

What is meant by Inspiratory Capacity?

Answer 7

Tidal volume plus inspiratory reserve volume.

Question 8

What is meant by Functional Residual Capacity?

Answer 8

Expiratory Reserve Volume plus Residual volume.

Question 9

What membrane lines the lungs?

Answer 9

The visceral pleural membrane.

Question 10

What membrane lines the inner surface of the ribs?

Answer 10

The parietal pleural membrane. Between the parietal and visceral membranes lies the intrapleural sac.

Question 11

What does Boyle’s law state?

Answer 11

That pressure exerted by a gas is inversely proportional to it’s volume.

Question 12

What are the primary muscles of inspiration?

Answer 12

External intercostals and the diaphragm.

Question 13

What muscles are used in expiration?

Answer 13

Passive at rest but if needed internal intercostals and abdominal muscles can be used.

Question 14

What is the Intra-thoracic Pressure?

Answer 14

Basically pressure inside the lungs. May be positive or negative relative to atmospheric pressure.

Question 15

What is meant by Intra-pleural Pressure?

Answer 15

Pressure in pleural cavity, negative in healthy lungs.

Question 16

What is meant by transpulmonary pressure?

Answer 16

Difference between alveolar or intra-thoracic pressure. Almost always positive because PT = Palv – Pip and Pip is negative.

Question 17

How might a pneumothorax occur?

Answer 17

Air enters pleural cavity due to injury, this causes intra pleural pressure to rise causing the lung to collapse.

Question 18

What drives airflow into the lungs?

Answer 18

Sub atmospheric alveolar pressure caused by chest expansion.

Question 19

In a healthy person what drives expiration?

Answer 19

Inspiratory muscles stop contracting allowing the elastic recoil of the chest wall and lungs to return them to their original size.

Question 20

What is surfactant and what does it do?

Answer 20

It’s a detergent like fluid secreted by type II pneumocytes. It reduces surface tension on the alveolar surface preventing their collapse. This increases compliance and makes breathing easier.

Question 21

In what alveoli is surfactant most effective?

Answer 21

Small alveoli rather than large as surfactant molecules come closer together and are therefore more concentrated.

Question 22

In what gestational period does surfactant production develop?

Answer 22

From 25-36 weeks. It is stimulated by thyroid hormones and cortisol.

Question 23

What is Infant Respiratory Distress Syndrome?

Answer 23

Disease suffered by premature babies due to insufficient surfactant production.

Question 24

What is meant by compliance?

Answer 24

Change in volume relative to change in pressure. It represents the stretchability of the lungs.