Question

wednesday 9/10: lung model lab

how do the muscles that control breathing help the respiratory system?

a) they contract to expand the lungs, allowing air to enter

b) they squeeze the lungs to push air out directly

c) they slow down breathing to conserve oxygen

d) they pump blood to the lungs

Explanation:

To solve this, we analyze each option:

• Option A: The diaphragm and intercostal muscles contract to increase thoracic volume, expanding lungs and allowing air (inspiration). This matches respiratory muscle function.
• Option B: Muscles don't "squeeze lungs" directly; expiration (air out) is often passive or uses muscle relaxation/other mechanisms, not direct squeezing.
• Option C: Breathing rate regulation is more about homeostasis (e.g., CO₂ levels), not conserving oxygen by slowing, and muscles don't primarily act this way.
• Option D: The heart pumps blood to lungs, not respiratory muscles.

Answer:

A) They contract to expand the lungs, allowing air to enter