Lecture 16

Question 1

What is included in the thoracic cavity?

Answer 1

Mediastinum: heart, vessels, pericardium

Pleural cavities: Lungs

Question 2

What are the boundaries of the thoracic cavity?

Answer 2

Anterior: sternum
Posterior: Thoracic Vertebrae 
Lateral: Ribs 
Superior: base of neck 
Inferior: diaphragm

Question 3

What happens if there is damage in the thoracic cavity?

Answer 3

the whole system will shut down

Question 4

Role of the Hilum?

Answer 4

Allows things toi enter

Question 5

Layers of the Pleural cavity?

Answer 5

Parietal pleura

Visceral pleura

Question 6

How is ventilation driven by pressure changes in thoracic cavity?

Answer 6

• Pressure is inversely proportional to volume.
• breathe in (volume increases)
• breathe out (volume decreases)

Question 7

What is Boyle’s Law

Answer 7

P = 1/V
Pressure inversely proportional to volume
- measured by collisions
Air will move to lower pressure space.

Question 8

Why is a pressure gradient important?

Answer 8

For us to breath air needs to move which requires a gradient. Between breaths there is no gradient because pressure inside cavity = pressure outside

Question 9

What are Anterior thoracic joints?

Answer 9

Areas of costal cartilage (hyaline) that can be synovial or cartilaginous and connects sternum to ribs.

Question 10

Sternocostal joints?

Answer 10

where they articulate

Synovial (except 1st which is cartilaginous

Question 11

Costochondral?

Answer 11

ribs-cartilage joint

Cartilaginous

Question 12

Interchondral?

Answer 12

don’t attach directly only to the cartilage

Synovial

Question 13

What are posterior thoracic joints?

Answer 13

Articulations between thoracic vertebrae and ribs

Synovial joints

Question 14

Costotransverse?

Answer 14

Between rib and transverse process of vertebrae

Question 15

Costovertebral?

Answer 15

Between rib and body of vertebrae

Question 16

Role of respiratory muscles?

Answer 16

they move the ribcage allowing us to breathe

Question 17

What are the primary inspiratory muscles?

Answer 17

Diaphragm and intercostals

Question 18

What are accessory muscles?

Answer 18

Active only when needed

Question 19

Structure of the diaphragm?

Answer 19

Sheet of skeletal muscle.

Dome shaped when relaxed and flattened when contracted.

Question 20

Function of diaphragm?

Answer 20

Separates thorax from abdomen.

Contraction expands thoracic cavity, compresses abdominopelvic cavity.

Question 21

Structure of Intercostal muscles?

Answer 21

Attach diagonally between neighbouring ribs. Internal and external…Internals lie in opposite direction to externals

Question 22

Function of external intercostals?

Answer 22

Lift ribcage and expands cavity.

Inspiration - quiet and forced

Question 23

Internal intercostals?

Answer 23

Depress ribcage and decrease cavity.

Expiration forced only.

Question 24

Difference between Forced and quiet breathing?

Answer 24

Forced = drawing more air in (talking), quiet = normal breathing

Question 25

What is thr role of accessory muscles?

Answer 25

Involved in forced breathing… some increase volume of cavity and other decrease volume.

Question 26

What muscles are involved in inspiration?

Answer 26

During quiet breathing the diaphragm contracts and flattens and External intercostals contract which lifts the ribs.
During forced breathing the same occurs but accessory muscles contract further to. expand thoracic cavity.

Question 27

What muscles are involved in expiration?

Answer 27

During quiet expiration the diaphragm relaxes making a dome shape and external intercostals relax so that ribs are not longer lifted.
During forced expiration the same occurs but internal intercostals lso contract to depress the ribs and accessory muscles contract to further decrease cavity volume.

Question 28

How do lungs expand as the cavity does?

Answer 28

Lung tissue is elastic and always trying to recoil.
The pleura make the lungs stick to the thoracic wall.
Expand during inspiration and decrease during expiration.

Question 29

Name the different pleura

Answer 29

Visceral pleura on lungs

Parietal pleura on thoracic cavity.

Question 30

Where is pleural fluid found?

Answer 30

Slippery surfaces for frictionless movement against other structures.
What causes lungs to stick to the thoracic wall.