1. 009 INTEGUMENT-1 Objectives: At the end of this practical you should be able to : 1. Identify the main features of non-hairy heavily keratinised skin and compare with thinner hairy skin. 2. Identify sebaceous and sweat glands. SLIDE 77 Digital Skin monkey Make a very low power diagram of the general structure as seen on slide 77. Identify and label: -thick stratum corneum -rest of epidermis -dermis (corium) -hypodermis Q 1. The stain used is Masson’s Trichrome. What colour is the stratum corneum? Q 2. What is stained green in the dermis? Q 3. What is the predominant tissue in the hypodermis? Q 4. What glands and their ducts can be seen in this section? SLIDE 76 or SLIDE 77 Make a detailed drawing (a few representative cells in each layer or stratum) of the epidermis only from either slide 76 (footpad of dog stained with H&E), or slide 77. Label the five strata; basale, spinosum, granulosum, lucidum (if visible) and corneum. 1 HEAVILY KERATINISED SKIN Q 5. In which of these layers might one observe Mitosis? Q 6. In which layer may be found Melanocyte (cell bodies)?

2. Q 11. what method of secretion does this gland utilise? 2 THINNER HAIRY SKIN SLIDE 74 Dorsal skin of dog SLIDE 83 Ventral abdominal skin of dog Compare the hair follicles in slides 74 and 83 Q 7. Which has the longest hairs? Q 8. Which has the most numerous hairs? Q 9. Why is there a difference? Make a low magnification diagram using one of these slides and identify and label the following: Epidermis Dermis (corium) Hypodermis Hair follicle (is this sectioned transversely, longitudinally or obliquely?) Sebaceous gland Apocrine sweat gland Arrector pili muscle Draw a high power diagram of a sebaceous gland Q 10. What is the arrector pili muscle?

3. 3 SLIDE 81 or SLIDE 82 Eyelid of horse Slide 81 is a Van Geisen stain, slide 82 is H&E stain. A very large modified gland opens onto the free margin of the eyelid. This is the Tarsal gland. Q 14. Of what type of skin gland is this a modification? Q 15. What is the function of this gland? Try to identify and draw an apocrine sweat gland. You may find SLIDE 82 is better for this. Q 12. Why is this gland called apocrine? Q 13. Where does the duct from this gland open? PLANUM NASALE SLIDE 84 Planum nasale of dog Examine this slide. Note the prominent grooves in the thick epidermal layer Do not draw.