Mechanics of Breathing

Question 1

Which is the only breathing process that is passive?

Answer 1

Expiration at rest

Question 2

What is the anagram for remembering the breathing process?

Answer 2

Muscles
(Movement)
Volume
Pressure
= (Air flow)

Question 3

Describe inspiration at rest (using MVP):

Answer 3

M: Diaphragm contracts and flattens, external intercostals contract -> rib cage moves out
V: Volume of thorax (and lungs) increases
P: Pressure decreases (same volume in large space)

Question 4

Describe expiration at rest (using MVP)

Answer 4

M: Diaphragm relaxes (dome shape), external intercostals relax -> rib cage moves down and in
V: Volume of thorax (and lungs) decreases
P: Pressure increases (same volume in smaller space)

Question 5

Describe inspiration during exercise (using MVP)

Answer 5

M: Diaphragm contracts and flattens, ext intercostals move up and out (recruit sternocleidomastoid (sternum) and pectoralis minor, scalene (ribs)
V: Lung volume increases (more than at rest)
P: Lung pressure decrease (more than at rest)

Question 6

Describe expiration during exercise (using MVP)

Answer 6

M: Diaphragm relaxes, ext intercostals move rib cage down and in (recruit internal intercostals and rectus abdominas)
V: Lung volume decrease (more than at rest)
P: Lung pressure increases (more than at rest)