HB-058 · Respiratory · Part
Diaphragm and breathing mechanics
Also called: breathing mechanics Diaphragma et mechanica respirationis
3D anatomy data Classes 6-8 · Classes 9-10 · Classes 11-12 Intermediate Draft - educator review
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Parts: diaphragm; external intercostals; rib movement; thoracic cavity
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About
Breathing in happens when the diaphragm flattens and ribs rise, enlarging the chest so air flows in.
- 📍 Where it is
- The dome-shaped diaphragm between chest and abdomen, with intercostal muscles between the ribs.
- 🧱 Structure
- Diaphragm with a central tendon; external and internal intercostal muscles; elastic lungs.
- ⚙️ What it does
- Inhalation (diaphragm and external intercostals contract) and quiet exhalation (muscles relax, lungs recoil).
💡 Key facts
- The diaphragm is the main breathing muscle.
- Hiccups are sudden diaphragm spasms.
- Quiet breathing out needs almost no muscle work.
✗ Lungs suck air in by themselves
✓ Muscles change chest volume; pressure differences move the air.
📒 Words to know
- inhalation
- breathing in
- exhalation
- breathing out
- diaphragm
- dome-shaped breathing muscle
🏫 Related lessons
- Animals: life processes and reproduction Classes 6-8
- Life processes Classes 9-10
- Yoga, breathing and mindfulness Classes 6-8
Generic GayaGnan topic lessons. Check your own board's syllabus for the exact chapter.
🔎 Sources and credits
Catalog description: Animated inhalation and exhalation.
- OpenStax Anatomy and Physiology 2e, ch. 22 (respiratory system) (accessed 2026-10-30)
- 3D models: BodyParts3D (DBCLS) and the Human Reference Atlas (HuBMAP), CC BY 4.0, with GayaGnan schematics. 3D model credits
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