Chest Wall and Breathing Mechanisms

Question 1

What is Boyle’s Law?

Answer 1

Pressure = 1/ volume

increase the pressure= decrease the volume

Question 2

Describe the pleura

Answer 2

Consists of the Parietal (on ribs) and the visceral (organ) pleura which are continuous at the hilum of the lungs.
The space between is filled with pleural fluid.

Question 3

Define the function of Pleural Fluid.

Answer 3

• Prevents friction between membranes

- Sticks the lungs to the ribcage so that expansion can occur.

Question 4

How does a pneumothorax occur?

Answer 4

A pneumothorax occurs when Air enters the pleural cavity and the adhesion is lost so the lungs recoil and don’t inflate.

Question 5

Breathing is dependent on Boyle’s law. explain.

Answer 5

Boyle’s law states that air will move from high to low pressures. It also states that volume is inversely related to pressure.
Breathe in= expand chest= greater volume= lower pressure= air moves in.

Question 6

Is breathing an active process?

Answer 6

Inspiration- active- uses external intercostal muscles and diaphragm. (also sternocleidomastoids and scalene.)
Expiration- passive.

Question 7

On exertion?

Answer 7

Expiration becomes an active process using Internal Intercostal and abdominal muscles.

Question 8

How do the movement of the ribs increase chest dimensions.

Answer 8

• Pump handle increases anterior-posterior dimensions.
  -Bucket Handle increases lateral dimensions
  The result is a 3D increase in dimensions.

Question 9

Name three important lung pressures.

Answer 9

Intra-Thoracic Pressure= inside the lungs
Intra-Pleural Pressure= Always Negative
Transpulmonary Pressure= PA- Pip= ALWAYS POSITIVE