A LITTLE LIGHTBULB MOMENT
Human anatomy and physiology
Diaphragm and inspiration
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The diaphragm drops, chest space grows, air rushes in.
The idea behind the cue
During inspiration, the diaphragm contracts and flattens, increasing thoracic volume. The pressure inside the lungs falls below atmospheric pressure, so air flows inward.
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Short & simple
The diaphragm drops, chest space grows, air rushes in.
Acronym
DTP — Dramatic Tacos Pirouette.
Story
A trampoline under the lungs yanks downward, the rib cage lifts like a bucket handle, and air pours in to fill the bigger room.
Connect the pieces
- D (Dramatic) → Diaphragm contraction: During inspiration, the diaphragm contracts and flattens.
- T (Tacos) → Thoracic expansion: That flattening increases thoracic volume.
- P (Pirouette) → Pressure drop: Pressure inside the lungs falls below atmospheric pressure, so air flows inward.
- Dramatic · Diaphragm contraction: During inspiration, the diaphragm contracts and flattens.
- Tacos · Thoracic expansion: That flattening increases thoracic volume.
- Pirouette · Pressure drop: Pressure inside the lungs falls below atmospheric pressure, so air flows inward.
Know the limits
Describes quiet inspiration; forced breathing also recruits accessory muscles.
Further reading · OpenStax science and mathematics textbooks ↗Check your understanding
What change directly pulls air into the lungs during inspiration?
A. Thoracic volume increases and intrapulmonary pressure decreases
B. Thoracic volume decreases and intrapulmonary pressure increases
C. Thoracic volume increases and intrapulmonary pressure increases
D. Thoracic volume decreases and intrapulmonary pressure stays unchanged
Reveal explanation
Thoracic volume increases and intrapulmonary pressure decreases
Air moves from higher to lower pressure, so expanding the thorax lowers lung pressure and draws air in.