Blood circulates through the heart, lungs, and body. Arteries carry blood away from the heart and veins return it; defining them only by oxygen content creates an error for the pulmonary vessels.
Trace the route before comparing vessels
Read this simplified route in order. The artery/vein distinction follows direction relative to the heart, not oxygen content alone. [HEART]
``mermaid
flowchart TD
A["Body return"] --> B["Right heart"]
B --> C["Lungs"]
C --> D["Left heart"]
D --> E["Blood sent to body"]
``
Text equivalent: blood returns from the body to the right heart, travels to the lungs, returns to the left heart, and is sent outward to the body. This is a teaching outline, not a complete anatomical map or a test of circulation.
A worked situation: Body to right heart
Fictional example. A learner traces oxygen-poor blood from the right side of the heart to the lungs, then oxygen-rich blood back to the left side and outward to the body.
Work through these questions: Body to right heart
| Question or field | Fictional completed example |
|---|---|
| First route? | Body to right heart |
| Second route? | Right heart to lungs |
| Third route? | Lungs to left heart |
| Fourth route? | Left heart to body |
| Definition check? | Arteries go away from the heart |