Layers of the Skin

Skin Structure

epidermis (outer layer), dermis, and subcutaneous tissue (hypodermis)

Epidermis

stratified squamous epithelium, cornified or keratinized to prevent water loss, avascular, and most cells are keratinocytes

Dermis

dense connective tissue

Subcutaneous Tissue (Hypodermis)

deep to dermis, not technically part of the skin, anchors skin to underlying organs, composed of mostly adipose tissue, senses as a shock absorber, and insulates deeper tissues

5 Layers of the Epidermis

stratum basale, stratum spinosum, stratum granulosum, stratum lucidem, and stratum corneum

Layers of the Epidermis

composed of 5 layers, avascular, covered from deepest to most superficial

Keratin

a fibrous protein that makes the epidermis tough

Stratum Basale

deepest layer of epidermis, lies next to dermis, wavy harderline with the demris anchor the two together, and cells undergo mitosis

Stratum Basle Daughter Cells

are pushed upward to become more superficial layers

Stratum Lucidum

formed from dead cells of the deeper stratum, occurs only in thick, hairless skin of the palms or hands and soles of feet

Stratum Corneum

outermost layer of epidermis, shingle like dead cells filled with keratin

Epidermal Dendritic Cells

alert and activate immune cells to a threat (bacterial/viral invasion)

Merkel Cells

associated with sensory nerve endings, and serve as touch receptors called merkel discs

Dermis Layers

papillary layer and reticular layer

Papillary Layer (upper dermal region)

projections called dermal papillae, some contain capillary loops, other house pain receptors and touch receptors, fingerprint are identifying films of sweat

Reticular Layer (deppest skin layer)

blood vessels, sweat, oil glands and deep pressure receptors

Lamellar Corpuscles

deep pressure receptors

Overall Dermis Structure

collagen, elastic fibers located throughout the dermis that give skin its toughness and elastic fibers give skin elsatically

Blood Vessels

play a role in body temperature regulation

Nerve Supply

sends messages to the central nervous system