Skin Structure and Function

Epidermis

Outermost layer of skin that keeps skin hydrated, produces new skin cells, and determines skin color.

Dermis

Middle layer of skin containing collagen, blood vessels, glands, hair follicles, and nerve endings, providing support and sensation.

Hypodermis

Innermost subcutaneous layer that stores energy, connects dermis to muscles and bones, and insulates the body.

Dermal Papillae

Protrusions into the epidermis that regulate hair growth.

Melanocytes

Cells that produce melanin, the pigment responsible for skin color.

Sweat Glands

Exocrine glands categorized into eccrine (temperature regulation) and apocrine (open into hair follicles, active from puberty).

Sebaceous Glands

Exocrine glands that secrete sebum into hair follicles, absent from palms, soles, and lips.

Stratum Corneum

The first defense layer of the epidermis.

Stratum Lucidum

A layer that thickens palms and soles.

Stratum Granulosum

A layer that forms a waterproof barrier.

Stratum Spinosum

Layer that contains keratinocytes.

Stratum Basale

The stem cell layer for skin regeneration.

Temperature Regulation

Mechanisms including sweat release, heat loss through radiation, conduction, convection, and evaporation.

Hypothermia

Condition of significantly lowered body temperature leading to shivering, confusion, and potential death if untreated.