9.1.4—Plan diagrams of trachea and bronchus walls

A plan diagram is a simplified representation of the visible organisation of a transverse section, not a drawing of every cell. For a trachea or bronchus, show the lumen and the main wall layers/features in their relative positions, then label only structures supported by the evidence.

1. Confirm the view: decide whether the evidence is a transverse wall section or a whole-system view; use the stated orientation and scale if available.
2. Set the outline: draw a clear, continuous simplified outline of the lumen and surrounding wall, keeping the relative arrangement rather than tracing every irregularity.
3. Place visible layers/features: add the ciliated lining next to the lumen, then show the supporting wall features that are actually visible, such as cartilage, smooth muscle or glands.
4. Preserve the level of organisation: for a whole-system diagram, keep the airway sequence and relative position of trachea, bronchi, bronchioles, alveoli and nearby capillary network; for a wall section, do not add structures outside the section.
5. Label evidence, not assumptions: use simple label lines that do not cross; label only visible or securely identifiable structures. Do not invent a precise scale, cell count or layer thickness.
6. Quality check: keep the drawing uncluttered, use continuous lines and no shading, and confirm that the plan diagram represents the observed arrangement without drawing individual cells.

The authenticated SME《Recognising Structures》provides labelled trachea and bronchus cross-section diagrams and structural evidence, but the session exposed no independent Observing & Drawing page or complete plan-diagram rubric; this method therefore states the evidence boundary rather than claiming a source-specific marking rule. No image generated or bound. Detailed tissue recognition belongs to 4617.