Question

what is the main function of the trachea in the respiratory system?
a. to transport air from the larynx to the bronchi
b. to contract and expand the chest cavity
c. to facilitate gas exchange in the alveoli
d. to filter air entering the nasal passages

which muscle plays a crucial role in the process of inhalation?
a. trapezius
b. intercostal muscles
c. abdominal muscles
d. diaphragm

how does oxygen enter the bloodstream from the lungs?
a. by active transport
b. by passing through the bronchioles
c. by diffusion through the alveolar walls
d. by being pumped through the trachea

Explanation:

1. For the trachea function: The trachea is a tubular airway that carries air from the larynx (voice box) down to the bronchi, which lead to the lungs. Other options describe functions of other respiratory structures.
2. For inhalation muscle: The diaphragm is the primary muscle of inhalation; it contracts and moves downward to expand the chest cavity, drawing air in. Intercostal muscles assist, but the diaphragm is the crucial primary muscle.
3. For oxygen entry to bloodstream: Oxygen moves from the alveoli (high oxygen concentration) to the bloodstream (low oxygen concentration) across the thin alveolar and capillary walls via passive diffusion.

Answer:

1. a. To transport air from the larynx to the bronchi
2. d. Diaphragm
3. c. By diffusion through the alveolar walls