Anatomy Test 3 ~ Epidermis, Dermis, & Hypodermis

Functions of the Skin

Protection, Temperature regulation, sensation, excretions production

5 Layers of the Epidermis (Surface to Deep)

Stratum Corneum, Lucidum, Granulosum, Spinosum, Basale

Stratum Corneum

Dead cells (20-30 cells thick), keratinized to protect deeper layers, regularly shed.

Stratum Lucidum

Thin, translucent cells found in palms of gangs and soles of feet.

Stratum Granulosum

Accumulate keratin granules and water-proof skin. Cells then flatten, disintegrate, then move up.

Stratum Spinosum

Irregular shaped cells, contain PRE-keratin filaments.

Stratum Basale

Cells divide and go up the layers.

Melanocytes

Epithelial cells that produce melanin.

Melanin

A pigment that is absorbed by nearby epidermal cells: it protects the skin against harmful UV rays

Dermis Structure

Dense irregular connective tissue; Contains nerves, blood vessels, sweat glands, and hair follicles.

Dermal Papillae

Wavy layer between the epidermis and the dermis.

Two layers of the Dermis

Papillary & Reticular

Papillary Layer

Loose connective tissue

Reticular layer

Bundles of collagen fibers

Hypodermis

Subcutaneous layer; Loose fatty connective tissue that connects skin to bone/muscle. It insulates and stores nutrients.