Ch. 5 The Integumentary System

Integumentary System

The system that includes skin, hair, nails, sweat glands, and sebaceous glands.

Epidermis

The superficial region of the skin that consists of keratinized stratified squamous epithelial tissue.

Dermis

The layer of skin that underlies the epidermis, consisting mostly of fibrous connective tissue; it is vascular and innervated.

Hypodermis

The subcutaneous layer beneath the skin, consisting mostly of loose adipose connective tissue.

Stratum Corneum

The outermost layer of the epidermis, consisting of flat, dead keratinocytes.

Stratum Lucidum

A clear layer found only in thick skin, consisting of thin, translucent dead keratinocytes.

Stratum Granulosum

The layer of the epidermis where keratinization begins; cells accumulate keratohyalin granules.

Stratum Spinosum

The layer of the epidermis with several cell layers thick known for its spiky appearance due to intermediate filaments.

Stratum Basale

The deepest layer of the epidermis, consisting of a single row of actively dividing stem cells.

Melanocytes

Cells in the stratum basale that produce the pigment melanin, which protects against UV radiation.

Keratinocytes

The major cells of the epidermis that produce fibrous keratin and are tightly connected by desmosomes.

Dendritic Cells

Star-shaped phagocytic cells located in the epidermis that play a key role in the immune response.

Tactile Cells (Merkel Cells)

Sensory receptors in the stratum basale that sense touch.

Eccrine Sweat Glands

The most numerous sweat glands that function in thermoregulation, releasing a watery secretion.

Apocrine Sweat Glands

Sweat glands confined to specific areas that secrete a thicker sweat containing fatty substances.

Sebaceous Glands

Glands that secrete sebum (oil) into hair follicles, providing lubrication and bactericidal properties.

Melanin

A pigment produced by melanocytes that gives skin its color and provides protection against UV radiation.

Carotene

A yellow to orange pigment that accumulates in the skin and can be converted to vitamin A.

Hemoglobin

Red pigment in red blood cells that can contribute to the pinkish hue of fair skin.

Cutaneous Sensations

Sensory perceptions, including touch and temperature, detected by cutaneous receptors in the skin.

Basal Layer

Another term for the stratum basale, where cell division occurs to produce new keratinocytes.

Keratinization

The process by which keratinocytes accumulate keratin and undergo structural changes as they move up to the surface.

Barrier Functions of Skin

The protective roles of skin including chemical, physical, and biological barriers against pathogens and injury.

Body Temperature Regulation

The process by which the skin helps maintain stable body temperature through vasodilation and vasoconstriction of blood vessels.

Immune Response Activation

Activation of the immune system by dendritic cells in the epidermis engaging with foreign antigens.

Blood Reservoir

The skin's ability to hold a significant volume of blood and direct it to other organs when needed.

Excretion

The process by which the skin can excrete waste products such as nitrogenous wastes via sweating.