Explain how the epithelial is adapted for its functions.

In this question you should point out the structural modifications of epithelial tissue to suit the different functions.

• One cell thick reduce diffusion distance in alveoli, kidney tubules, and blood capillaries
• Flattened, plate-like squamous cells provides smooth surface for easy flow of materials along the tissue, e.g. blood capillaries
• Secretory cells secrete hormones and enzymes e.g. in thyroid gland and chief gland
• Microvilli increase absorptive surface
• Transitional epithelium allows distension of bladder
• Stratified epithelia offer protection from friction
• Ciliated epithelia allow movement of particles example dust in trachea and ova in fallopian tube
• Deposit of keratin allows protection
• Pseudo stratified for stretching