Mechanics of breathing

Question 1

Name the five mechanisms of breathing (mm veggie pie)

Answer 1

• Muscles
• Movement
• Thoracic cavity volume
• Lung air pressure
• Inspiration/ Expiration

Question 2

Why are muscles a mechanism of breathing?

Answer 2

They contract or relax to cause movement

Question 3

What does movement relate to as a mechanism of breathing?

Answer 3

Movement of the ribs, sternum and abdomen

Question 4

In active inspiration at rest, what do the muscles do?

Answer 4

• Internal intercostal muscles contract

- Diaphragm contracts (lowers)

Question 5

During passive expiration at rest, what do the muscles do?

Answer 5

• External intercostals passively relax

- Diaphragm passively bows upwards (relaxes)

Question 6

Describe the mechanics of breathing inspiring at rest

Answer 6

• Internal intercostals and diaphragm contract (lowers)
• Ribs and sternum move up and out
• Volume of thoracic cavity increases
• Pressure in the lung tissue decreases below the atmospheric pressure

Question 7

Describe the mechanics of breathing inspiring during exercise

Answer 7

• Internal intercostals, scalenes, SCM, diaphragm and pectoralis minor actively contract
• Greater movement of the ribs and sternum up and out
• Volume increases quicker
• Pressure decreases quicker

Question 8

Describe the mechanics of breathing expiring at rest

Answer 8

• Internal intercostal and diaphragm relax
• Ribs and sternum move in and down
• Volume decreases
• Pressure increases

Question 9

Describe the mechanics of breathing expiring during exercise

Answer 9

• Internal intercostals and diaphragm relax and the rectus abdominis contract
• Greater movement in and down
• Volume decreases quicker
• Pressure increases quicker