Layers of the epidermis

Stratum corneum:

horny layer, 20–30 rows of keratinocytes.Stratum lucidum:

Stratum lucidum

clear layer, translucent flattened dead cells.

Stratum granulosum:

granular layer, middle layer where cells degenerate.

Stratum spinosum:

spiny layer, where Langerhans cells are found.

Stratum germinativum / stratum basale:

 basal layer, single row of cells where division starts.

Epidermis of hairy skin

Hairy skin has 3 epidermal layers rather than 5: stratum corneum, stratum spinosum, and stratum basale.
It also has scalelike folds on the skin surface, tactile elevations called epidermal papillae, and tactile hairs called tylotrich hairs.

Dermis

The dermis makes up the greatest portion of the integument and is the “hide”.
It is highly fibrous dense irregular connective tissue with collagen, elastic, and reticular fibers.
It also contains hair follicles, nerve endings, glands, smooth muscle, blood vessels, lymphatic channels, fibroblasts, adipocytes, and macrophages.

Hypodermis

The hypodermis, or subcutaneous layer, lies below the dermis.
It is a thick layer of loose areolar tissue that allows the skin to move freely over underlying structures.
Its fibers are continuous with the dermis and it contains adipose tissue, blood and lymphatic vessels, nerves, and Pacinian corpuscles

Arrector pili muscles

The arrector pili is a small smooth muscle attached to each hair follicle.
It is innervated by the sympathetic nervous system, and contraction pulls the hair erect.