Thorax and Breathing

Question 1

What is the shape of the thorax?

Answer 1

Cone-shaped

Question 2

Where does the thorax extend from and to?

Answer 2

From the sternum to the vertebral column: T1-T12

Question 3

What is the central portion of the thorax?

Answer 3

The mediastinum

Question 4

What is an aperture?

Answer 4

An opening

- The thorax has a superior and inferior one

Question 5

What are the shape of the lungs?

Answer 5

Cone shaped

Question 6

Where do the lungs extend from?

Answer 6

From the diaphragm to a point above the clavicle

Question 7

Where do primary bronchi and blood vessels enter the lungs?

Answer 7

The hilum

Question 8

What is the top of the lungs called?

Answer 8

The apex

Question 9

How many lobes does the right lung have?

Answer 9

3

Question 10

How many lobes does the left lung have?

Answer 10

2

Question 11

What are the lobes in the left lung separated by?

Answer 11

The oblique fissure

Question 12

What are the lobes in the right lung separated by?

Answer 12

The oblique and horizontal fissures

Question 13

If you don’t examine the back of a patient what are you missing in relation to the lungs?

Answer 13

The inferior lobe

Question 14

Around the lungs there is a double fold of pleura. What are pleura?

Answer 14

A serous membrane enveloping the lungs

Question 15

What does pleura allow for?

Answer 15

Smooth movement of the lungs in the chest cavity

Question 16

What is the function of parietal pleura?

Answer 16

• Parietal: relating to the wall of a body or body cavity or hollow structure
• Lines whole of thoracic cavity
• Adheres to internal surface of the ribs and superior face of the diaphragm
• Partitions off the mediastinum (helps divide left lung from right lung and heart in the middle)

Question 17

What is the function of the visceral pleura?

Answer 17

• Lies against the parietal pleura and covers the outer surface of the lung

Question 18

What does the space between the 2 layers of pleura produce?

Answer 18

Produces pleural fluid which prevents friction

Question 19

What is the costodiaphragmatic recess?

Answer 19

The cleft-like extension of the pleural cavity between the diaphragm and the rib-cage

Question 20

What are the muscles of the thorax of critical importance to?

Answer 20

Respiration

Question 21

Internal intercostal muscles are some of the muscles of the thorax. What do these muscles do?

Answer 21

Depress ribs

Question 22

External intercostal muscles are some of the muscles of the thorax. What do these muscles do?

Answer 22

Elevate ribs

Question 23

The diaphragm is a major muscle of the thorax. What does this muscle do?

Answer 23

Enlarges the thorax as it contracts and moves downwards

Question 24

The quadratus lumborum (which is attaches to the bottom rib (12)) is a muscle of the thorax. What does this muscle do?

Answer 24

Depresses the last rib

Question 25

What are the accessory muscles used in respiration?

Answer 25

Sternocleidomastoid: Raises clavicle in forced inspiration

Scalene muscles: raise the first rib in forced inspiration

Pectoralis major: can be used to help widen the thorax in forced inspiration

Question 26

Contraction of what alone produces quiet inspiration?

Answer 26

The diaphragm: it moves downwards in quiet inspiration, increasing the capacity of the thoracic cavity
- External intercostal muscles may help, but are used more obviously in forced inspiration (illness/sports)

Question 27

What is the process of expiration?

Answer 27

• Inspiratory muscles relax causing a decrease in the size of the thorax
• Diaphragm moves upwards
• Internal intercostal muscles move the rib cage downwards
• The elastic recoil of the lung tissue aids expiration

Question 28

What is the blood-air barrier composed of?

Answer 28

• Capillary endothelium-basement membrane
• Interstitial space
• Basement membrane of alveolus
• Alveolar epithelium