Question

1. what is the role of the diaphragm in breathing?

a) filters air
b) contracts to expand the lungs during inhalation
c) pumps blood through the lungs
d) stores air for later exhalation

1. what happens to thoracic volume when the diaphragm contracts?

a) volume decreases
b) pressure increases
c) volume increases
d) lungs collapse

1. during inspiration, what happens to the diaphragm?

a) it contracts and moves downward
b) it relaxes and moves upward
c) it remains still
d) it pushes air out of the lungs

1. during expiration, which statement is true?

a) diaphragm contracts and volume increases
b) diaphragm relaxes and air exits the lungs
c) thoracic cavity expands
d) pressure inside lungs decreases

1. what role do the intercostal muscles play in breathing?

a) filter incoming air
b) relax the diaphragm
c) pull the ribs up during inhalation
d) prevent lung collapse

1. which structure filters air using cilia and mucus?

a) bronchioles
b) trachea
c) alveoli
d) diaphragm

Explanation:

1. The diaphragm contracts (flattens) during inhalation, increasing thoracic volume and expanding the lungs.
2. When the diaphragm contracts, it moves downward, increasing the thoracic cavity volume.
3. During inspiration (inhalation), the diaphragm contracts and moves downward to create space for air to enter the lungs.
4. During expiration (exhalation), the diaphragm relaxes (moves upward), thoracic volume decreases, and air exits the lungs.
5. Intercostal muscles (external intercostals) contract during inhalation to pull the ribs up and out, increasing thoracic volume.
6. The trachea has cilia and mucus that trap dust and particles, filtering the incoming air.

Answer:

1. B. Contracts to expand the lungs during inhalation
2. C. Volume increases
3. A. It contracts and moves downward
4. B. Diaphragm relaxes and air exits the lungs
5. C. Pull the ribs up during inhalation
6. B. Trachea