9.06 Practicals: Airways

Purpose of Activity

• To practice and apply biological drawing skills by creating an accurate, detailed drawing of a tracheal section.
• To understand structural anatomy of the trachea, including cartilage, muscle, and tissue arrangement.

Preparation Steps

1. Review Drawing Guidelines

• Read Practical in Chapter 7 for general biological drawing guidelines:
  • Accurate representation: Draw exactly what is seen, with correct proportions.
  • Clarity and labeling: Use neat, unshaded lines and clearly label structures.
  • Scale and magnification: Include a scale bar if possible, and specify magnification level.

1. Consult Practical Workbook

• Review Practical Investigations Chapter 7:
  • These sections cover additional guidance on drawing techniques and specifics on tracheal histology.
  • Ensure familiarity with cell types and structures typically visible in a tracheal section.

Instructions for Drawing the Tracheal Section

1. Set Up Slide and Microscope

• Mount the tracheal slide and adjust the microscope to obtain a clear, magnified view (×4 magnification).
• Observe the orientation: Front of the neck is at the top of the section; back of the trachea is at the bottom.

1. Key Structures to Include in the Drawing

• Cartilage Rings:
  • Identify the C-shaped rings of hyaline cartilage surrounding most of the trachea.
  • The cartilage should be drawn as incomplete rings, with a gap at the back (posterior) of the trachea.
  • Provide clear lines for cartilage edges and label as “Cartilage Rings”.
• Smooth Muscle Band:
  • Draw and label the smooth muscle band located at the back of the trachea, filling the space between the ends of the cartilage rings.
  • Label as “Smooth Muscle”; indicate that it serves to allow tracheal flexibility and diameter adjustment.
• Epithelium:
  • Draw the inner lining of the trachea, noting the ciliated epithelium.
  • This layer should be labeled as “Ciliated Epithelium” to highlight its role in moving mucus out of the respiratory tract.
• Connective Tissue:
  • Identify and draw the connective tissue that lies between the cartilage rings and the epithelium.
  • Label as “Connective Tissue” to indicate its structural and supportive function.

1. Drawing Specifications

• Magnification: Clearly indicate that the drawing is at ×4 magnification.
• Orientation Labels:
  • Mark the top of the drawing as the front of the neck.
  • Mark the bottom as the back of the trachea.
• No shading: Use only outline lines to maintain clarity.
• Label Placement: Place labels neatly with horizontal lines pointing to each structure.

Additional Notes

• Scale Bar (Optional): Add a scale bar if possible, to indicate the approximate size of structures at ×4 magnification.
• Focus on Detail: Aim to capture any cell layers and structural differences observed, including varying thicknesses or textures.
• Accuracy and Proportion: Structures should be represented with correct relative sizes to aid in understanding functional anatomy.