Anatomy of chest wall and mechanics of breathing

Question 1

Boyle’s Law

Answer 1

The pressure exerted by a gas is inversely proportional to the volume

Question 2

Do gases move from low to high or high to low pressure?

Answer 2

High to low

Question 3

What 3 structures bind the lower respiratory tract?

Answer 3

Ribs, Spine and diaphragm

Question 4

What lines the lungs and interior thorax?

Answer 4

Pleural membranes

Question 5

What kind of fluid fills the pleural sac?

Answer 5

Intra pleural fluid

Question 6

What are the 2 types of pleural membranes (pleura)?

Answer 6

Parietal and visceral

Question 7

What causes the lungs to “stick” to the rib cage?

Answer 7

The pleural membranes

Question 8

Pleurisy

Answer 8

Inflammation of pleura

Question 9

Pneumothorax

Answer 9

The abnormal collection of air in the pleural space that causes an uncoupling of the lung from the chest wall

Question 10

Is intra pleural pressure positive or negative in comparison to atmospheric pressure?

Answer 10

Negative

Sub atmospheric

Question 11

Due to elastic recoil state what direction the ribs and lungs want to go

Answer 11

Ribs - want to pull chest outwards

Lungs - want to pull inwards

Question 12

What is the name of the force which sticks the ribs and lungs together

Answer 12

Cohesive force

Question 13

Muscles used for inspiration (4)

Answer 13

External intercostals
diaphragm
sternocleidomastoids
Scalenes

Question 14

What muscles does expiration use 1- at rest and 2 - during severe respiratory load?

Answer 14

1 - None

2 - Internal intercostals and abdominal muscles

Question 15

State of diaphragm at rest

Answer 15

Relaxed after expiration and before inspiration

Question 16

State of diaphragm during inspiration

Answer 16

Contracted as thoracic volume increases as the diaphragm collapses

Question 17

State of diaphragm during expiration

Answer 17

Relaxed as the diaphragm rises and thoracic volume decreases

Question 18

Intercostals - pump handle explanation

Answer 18

Anterior-posterior dimension
Vertebrae->rib->sternum
Rub moves up to increases protrusion from anterior

Question 19

Intercostals - Bucket handle explanation

Answer 19

Lateral dimension to make the chest wider

Question 20

What is asthma?

Answer 20

Over reactive constriction of bronchial smooth muscle which therefore increases the resistance making expiration difficult

Question 21

What forces are airways pulled open by?

Answer 21

Physical forces of inspiration

Question 22

What forces are airways compressed by?

Answer 22

Physical forces of expiration

Question 23

What happens to the lung in pneumothorax? Why?

Answer 23

The sealed pleural cavity is opened causing air to flow in from high atmospheric pressure to the lower intrapleural pressure and do the lung collapses to the un stretched size as it uncouples from the chest wall

Question 24

Alveolar pressure (PA)

Answer 24

Pressure in the lungs which may be positive or negative

Question 25

Intrapleural pressure (Pip)

Answer 25

Pressure in pleural cavity

Always negative relative to atmosphere

Question 26

Transpulmonary pressure (PT)

Answer 26

PT=PA-Pip
Always positive
Pressure difference across lungs

Question 27

Alveolar pressure => subatmospheric

Answer 27

Air in

Question 28

Alveolar pressure => above atmospheric

Answer 28

Air out