1. Integument
Department of Biology, WCU

2. Functions of skin Protection Temperature regulation Secretion
Sensory perception

3. Introduction Covering Contains Thickness 3 layers
blood vessels, nerves, glands, receptors
Thickness
3 layers
epidermis
dermis
hypodermis

4. Epidermis
Derived from ……
Non-vascularized
Layered
Stratified squamous

5. Epidermal layers 1. Corneum 2. Lucidum dead 2/3 thick replaced
only thick skin
thin

6. Epidermal layers 3. Granulosum 4. Spinosum 5. Basale flat glycoprotein
keratinized
5. Basale
single row
mitosis

7. Epidermal cells 1. Melanocytes 2. Langerhans cells 3. Merkel cells
melanin: skin color and protection
2. Langerhans cells
bone marrow, immune response
3. Merkel cells
sensory function
4. Keratinocytes
protection

8. Dermis
Derived from ……
Highly vascularized
Innervated
Tatoos

9. Dermal layers 1. Papillary layer - thin, loose connective tissue
- dermal papillae

10. Dermal layers 2. Reticular layer - 80% - dense connective tissue
- nerves, glands, blood vessels

11. Hypodermis Shares characteristics of skin Functions anchorage
absorbs shock
prevents heat loss

12. Epidermal derivatives
1. Hair (pili)
warm, sensing, protection
growth: dermis/hypodermis
arrector pili

13. Epidermal derivatives
2. Nails
from lucidum, corneum

14. Epidermal derivatives
3. Glands
sweat glands
Eccrine (hands, feet)
Apocrine (genitals)
oil glands (sebum)
Lubrication
Kills bacteria
Reduce water loss