Integument Layers and Subcutaneous Layer

Stratum lucidum

2-3 layers of anucleate, dead keratinocytes; seen only in thick skin (i.e., palms of hands, soles of feet)

Stratum granulosum

3-5 layers of keratinocytes with distinct granules in cytoplasm; keratinization begins in this layer

Reticular layer

Deeper layer of dermis; composed of dense irregular connective tissue; surrounds and supports hair follicles, sebaceous glands and sweat glands, nerves, and blood vessels

Stratum corneum

Most superficial layer of epidermis: 20-30 layers of dead, flattened, anucleate, keratin-filled keratinocytes

Subcutaneous layer

Not considered part of the integument; deep to dermis; composed of areolar and adipose connective tissue

Stratum spinosum

Several layers of keratinocytes attached to neighbors by desmosomes; epidermal dendritic cells present

Stratum basale

Single layer of cuboidal to low columnar keratinocytes in contact with basement membrane; cell division occurs here; also contains melanocytes and tactile cells

Papillary layer

Superficial layer of dermis; composed of areolar connective tissue; forms dermal papillae; houses capillaries and tactile receptors