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BIO 304 . WEEK 2 . MONDAY . LAB WORKBOOK
Epithelial Tissue Classification
Naming epithelia by cell shape and number of layers, plus pseudostratified and transitional.
Print this page. You will draw your own diagrams from the directions below, then hand-label the structures listed. Drawing by hand is the integrity mechanism for this course.
1A. What you will draw
Epithelial tissues are named by two features: how many layers of cells (simple, stratified) and the shape of the surface cells (squamous, cuboidal, columnar). Plus two special cases: pseudostratified (looks layered, isn't) and transitional (changes shape as it stretches). Draw them all.
Box A. The six basic epithelial types (3 by 2 matrix)
Directions
- Draw a 3-by-2 grid. Columns are cell shape: Squamous (flat), Cuboidal (square), Columnar (tall). Rows are layers: Simple (one layer), Stratified (many layers).
- In each cell of the grid, sketch the tissue. Show the basement membrane as a thin dark line at the bottom.
- Inside each sketch, write ONE typical location (e.g., simple squamous: alveoli; simple cuboidal: kidney tubules; simple columnar: small intestine; stratified squamous: skin epidermis; stratified cuboidal: large gland ducts; stratified columnar: rare, parts of male urethra).
- Cell nuclei should reflect the shape: round in cuboidal, oval in columnar, flat in squamous.
Draw here. Sketch by hand.
Box B. Pseudostratified and transitional epithelium
Directions
- Left half: draw pseudostratified columnar epithelium with cilia at the top. Show cells of different heights all touching the basement membrane. Add nuclei at staggered heights. Label cilia and goblet cells.
- Note: only one layer, but appears layered due to nuclei at different heights. Common in the respiratory tract.
- Right half: draw transitional epithelium in two states. Left side: empty bladder, cells stacked many layers high, surface cells rounded. Right side: full bladder, fewer apparent layers, surface cells flattened.
- Label transitional epithelium and note its location (urinary tract).
Draw here. Sketch by hand.
1C. Structures to label (13)
After you finish each drawing, label every structure below directly on your sketch.
- Basement membrane
- Simple squamous
- Simple cuboidal
- Simple columnar
- Stratified squamous
- Stratified cuboidal
- Stratified columnar
- Pseudostratified columnar
- Transitional
- Cilia
- Goblet cell
- Apical surface
- Basal surface
Part 2 of 2
Physiology Lab
2A. Match tissue to location and function
For each location below, identify (a) the epithelial type present, and (b) the function being served by that tissue's specific structure. Write in complete sentences.
1. The wall of the alveolus in the lung.
2. The lining of the kidney tubule.
3. The lining of the small intestine.
4. The outer surface of the skin.
5. The lining of the trachea.
6. The lining of the urinary bladder.
2B. Synthesis questions
Answer each in 2 to 4 sentences. Use the language from this week's lecture and your drawings as evidence.
1. Predict the tissue type you would find lining a surface where rapid diffusion is essential. Justify, and give an example location.
2. Transitional epithelium has the unusual property of changing apparent shape. Explain why this is functionally important in the bladder and what would happen if it were stratified squamous instead.
3. Cigarette smoke damages pseudostratified ciliated columnar epithelium in the airways. Predict the consequences for mucociliary clearance and explain why a chronic smoker's cough is often productive.
3. What to submit
Complete both the Anatomy Lab (your own drawings, hand-labeled, plus the structures list) and the Physiology Lab (activity and synthesis questions). Photograph or scan every page and upload to Canvas before the deadline listed on the schedule. Hand-drawn, hand-labeled work is the integrity mechanism for this course. Typed or AI-generated diagrams are not accepted.