01 / Location & anatomical relationships
Separating the chest from the abdomen, below the lungs.
02 / Structure & organization
The diaphragm has a central tendon and muscular attachments to the sternum, ribs and lumbar region. The phrenic nerves supply its motor function. Openings transmit the inferior vena cava, esophagus and aorta at different levels.
03 / Function
When it contracts, it helps draw air into your lungs.
04 / Mechanism
This dome-shaped muscle flattens when it contracts. The chest cavity becomes larger, pressure falls and air moves into the lungs. When it relaxes, the chest becomes smaller and air can move out.
Working together: respiratory system
Your diaphragm contracts to help draw air in. Air reaches your lungs, where oxygen crosses into the blood through the walls of tiny air sacs.
Meet this body system →Working together: muscular system
When you bend your elbow, some muscles contract while others relax. Their coordinated pull moves the bones at the joint.
Meet this body system →FOR DEEPER STUDY
Connect structure with function
Contraction lowers its dome, expanding thoracic volume and raising abdominal pressure. Breathing therefore involves coordinated movement of both thoracic and abdominal compartments.
Check your understanding
Locate the diaphragm in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.