ANAT 101 Lecture Notes - Merocrine, Acne Vulgaris, Eccrine Sweat Gland

• School: Queen's University
• Department: Anatomy and Cell Biology
• Course: ANAT 101
• Professor: Richard Oko

Document Summary

Composed of a) epidermis (superficial epithelium) b) dermis (underlying connective tissues) Hypodermis/subcutaneous layer: deep within dermis: accessory structures. The epidermis: stratified squamous epithelium of different layers. Thin skin: 4 layers: strata: layers of skin. *basement membrane: separates epidermis from underlying dermis stratum corneum: exposed surface, contains 15-30 layers of keratinized/cornified dead cells. Cells are connected through desmosomes -> shed in large groups/sheets. Each time a stem cell divides, one of the resulting daughter cells enters the next layer. Forms epidermal ridges that extend into dermis (finger prints) Ridges and papillae (dermal projections that extend upward) increase surface area for diffusion between dermis and epidermis. Pigmentation: contains 2 pigments, carotene: orange-yellow pigment accumulated in epidermal cells, melanin: brown, yellow-brown, or black pigment produced by melanocytes near stratum basale cells. *some melanocytes produce less melanin -> varied skin colours. Benefits of sunlight on skin: vitamin d.