Practice Flashcards
Flip to reveal answersWhat is ventilation?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 13 Flashcards — Ventilation mechanics
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is ventilation?
Answer
The movement of **air into and out of the lungs** (breathing) — it keeps fresh air at the gas-exchange surface.
Question
Do the lungs have their own muscle to pull air in?
Answer
**No** — lungs have no muscle. The **diaphragm** and **intercostal muscles** change the chest's volume to move air.
Question
What is the diaphragm and what does it do when it contracts?
Answer
A sheet of muscle below the lungs. When it **contracts** it **flattens and moves down**, increasing the volume of the thorax.
Question
Where are the intercostal muscles, and what do the external ones do during inhalation?
Answer
Between the ribs. The **external intercostals contract** to pull the ribs **up and out**.
Question
Give the cause-effect chain for breathing.
Answer
**Muscles → volume → pressure → air flow.** Muscles change the volume, which changes the pressure, and air moves down the pressure gradient.
Question
During inhalation, what happens to thoracic volume and pressure?
Answer
Volume **increases**, so pressure **falls below atmospheric** — and air flows **in**.
Question
During exhalation, what happens to thoracic volume and pressure?
Answer
Volume **decreases**, so pressure **rises above atmospheric** — and air flows **out**.
Question
Why does air flow into the lungs during inhalation?
Answer
Because the pressure inside has **fallen below atmospheric**, and air always moves from **high to low** pressure.
Question
Is resting exhalation active or passive?
Answer
**Passive** — the muscles simply **relax** (no contraction needed); the diaphragm domes up and the ribs drop.
Question
What causes the thorax to expand during inspiration?
Answer
The **diaphragm and external intercostal muscles contracting**.
Question
Name a muscle group besides the diaphragm that contracts to cause inspiration.
Answer
The **external intercostal muscles**.
Question
On a lung-pressure trace, how do you spot inhalation versus exhalation?
Answer
Pressure **below** atmospheric = **inhaling** (volume rising); pressure **above** atmospheric = **exhaling** (volume falling).
Question
How do volume and pressure change relative to each other?
Answer
In **opposite** directions — bigger volume means lower pressure, smaller volume means higher pressure.
Read the notes
Full study notes for Ventilation mechanics
Topic 2.6 hub
Gas exchange
More from Topic 2.6
All flashcards in this topic
Biology exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free