Integumentary System: Skin Structure and Function

The skin and its accessory structures (hair, nails, glands, sensory receptors).

The largest organ by weight, composed of several tissue types.

Outer layer of the skin composed of stratified squamous epithelium.

Inner layer of skin, thicker than the epidermis; connective tissue with collagenous and elastic fibers, muscle, blood and nervous tissue

Layer beneath the dermis; an insulating layer made of areolar and adipose connective tissue, not considered part of the skin.

Deepest layer of epidermis, nourished by blood vessels in the dermis.

Process of hardening, dehydration, and keratin accumulation in epidermal cells as they migrate outward.

Tough, fibrous, waterproof protein made and stored in the cells.

Outermost layer of epidermis, formed as cells reach outer surface, become tightly packed, develop desmosomes.

Cells in epidermis that are phagocytes; protect skin and underlying tissues from infection.

Cells in epidermis that act as sensory receptors for light touch.

Cells in epidermis that produce the pigment melanin.

Brownish-black pigment of epidermis.

Reddish-yellow pigment found in certain areas.

Inherited mutation in melanin genes; lack melanin.

Arise from epithelial cells in skin

Arise from melanocytes.

Projections in dermis between epidermal ridges.

Superficial layer of the dermis.

Accessory structures originating from epidermis, extending into dermis or hypodermis.

Visible portion, keratinized cells, overlies nail bed.

Surface of skin under nail plate.

Active growth region, not visible, at proximal end of nail bed.

Tube-like depression of epidermal cells from which hair develops; extends into dermis or subcutaneous layer.

Attached to hair follicle; contracts in response to cold or fear, and causes goosebumps.

Glands associated with hair follicles that produce sebum.

Holocrine glands that produce sebum, consisting of fatty material and cellular debris.

Acne vulgaris is a disorder

Glands widespread in skin originating in deeper dermis or hypodermis as ball-shaped coils.

Sweat glands that secrete mainly water, some salts, wastes; respond to elevated body temperature, open to body surface through pores.

Sweat glands in axillary and groin areas that open into hair follicles; respond to emotions and pain.

Skin glands that secrete ear wax

First is Protective barrier: Protects against harmful substances, UV radiation, microorganisms, water loss. Second is Sensation: Contains sensory receptors for touch, pressure, temperature changes, pain. Third is Excretion of some wastes. Fouth is Production of Vitamin D: Starts in skin; when produced and activated, helps with calcium absorption. Fifth is Regulation of body temperature: Helps cool body by sweating and blood flow changes

Primary method of heat loss; infrared heat rays travel from warmer skin to cooler environment.

Heat moves from warmer skin to cooler objects it is in contact with.

Heat loss from skin into circulating air currents.

Heat is lost through sweat as it evaporates, and carries heat away from the skin.

Abnormally high body temperature

Abnormally low body temperature

A normal response to injury or stress.

Affects only the epidermis

Reaching dermis or subcutaneous layer, results in blood vessels breaking; released blood forms a clot

Injures only epidermis, as in sunburn; redness, heat, inflammation; healing takes days to weeks, no scarring.

Destroys epidermis and some dermis, as in burn from hot liquid; may blister, healing varies with severity and stem cell survival; usually recovers completely, no scarring.

Destroys epidermis, dermis, accessory structures; results from prolonged exposure to heat, flames, hot liquids; often requires skin graft, skin substitutes.