Anatomy: Layers of the Skin

Stratum Basale

deepest epidermal layer attached to the dermis along a wavy borderline

Stratum Basale

mostly a single row of the youngest cells that produce keratin

Stratum Basale

divides rapidly to provide new cells for the top layers

Stratum Basale

may contain cells that produce melanin and those that in conjunction with a nerve to help to sense touch (Merkle cells)

Stratum Spinosum

prickly layer

Stratum Spinosum

several cell layers thick and is responsible for production tension-resisting pre-keratin filaments

Stratum Granulosum

three to five layers of flattened cells that start to accumulate the granules that become keratin and those that will become waterproof glycolipids to be placed in the extracellular space to slow the loss of water across the epidermis

Stratum Granulosum

cell membrane thickens making the cells more resistant to destruction

Stratum Lucidum

clear layer

Stratum Lucidum

only present in “thick” epdiermis

Stratum Lucidum

begins the layers of flattened dead cells that protect the body

Stratum Corneum

consists of 20-30 layers of dead cells that contain keratin, thickened membranes, and lipids

Stratum Corneum

durable protective barrier to the hostile external environment

Papillary Layer

made of areolar connective tissue

Papillary Layer

the superior surface has projections called dermal papillae that cause indents in the epidermis above. 

Papillary Layer

These projections may contain capillary loops for nutrition, nerve endings, or touch receptors called meissner’s corpuscles.

Papillary Layer

On the palms of the hands and soles of the feet these projections cause ridges that increase the epidermis’ gripping ability. 

Papillary Layer

These genetically determined ridges and sweat glands that exist along the crests create our identifying fingerprints.

Reticular layer

dense irregular connective tissue that contain thick bundles of collagen fibers that mostly run parallel to the skin and each other.

Reticular Layer

Areas where the fibers are parallel are called cleavage or tension lines and are important to surgeons because when incisions are made parallel to these line the cut does not gape as much and heals faster.

Reticular layer

blood vessels, sweat and oil glands, deep pressure receptors (Pacinian corpuscles), and phagocytes act to prevent bacteria from penetrating more deeply into the body