INTEGUMENTARY SYSTEM REVIEW Function Term Integumentary System The outermost layer of the skin that consists of stratified squamous epithelial tissue. Dermis Found in the upper layers of the dermis, they create your fingerprint pattern. Hypodermis Small epidermal structures with nerve endings that are sensitive to touch and pressure. Pacinian (Lamellar) Corpuscle A layer of the epidermis found only in the thick skin of the fingers, palms, and soles. Stratum Basale (Germinativum) 1 A 3 to 5 cell layer in the epidermis and considered a transitional layer sandwiched between the metabolically active layers beneath and the non-viable layer (as it contains dead cells) above. It is also referred to as the granular layer, as the cells contain irregularly shaped granules. Stratum Spinosum The outermost layer of the epidermis, which consists of flattened, keratinized cells. Keratinocytes A tough, fibrous protein that replaces the cytoplasm and nucleus in each cell. Melanocytes Yellow-brown or black pigment. Carotene Special macrophages that serve as antigen-presenting cells in the skin. 2 Merkel’s Cells Part of hair that is above the epidermis but is not anchored to the follicle. Root Hair Plexus (Hair Follicle Receptor) Layer that supplies nutrients to select layers of the epidermis and regulates temperature. Reticular Layer Mass of connective tissue, blood capillaries, and nerve endings at the base of the hair follicle. Hair Follicle Structure at the base of the hair root that surrounds the dermal papilla. Hair Root 3 Layer of basal cells from which a strand of hair grows. Cortex In hair, the innermost layer of keratinocytes originating from the hair matrix. Connective Tissue Root Sheath A covering of epithelium produced by the matrix that surrounds the root of the hair. External Epithelial Root Sheath Layer of connective tissue that surrounds the base of the hair follicle, connecting it to the dermis. Cuticle Main keratinous plate that forms the nail. Hyponychium 4 Basal part of the nail body that consists of a crescent-shaped layer of thick epithelium. Nail Bed Type of oil gland found in the dermis all over the body and helps to lubricate and waterproof the skin and hair by secreting sebum. Sebum These glands open into the hair follicle and secrete an oily substance called sebum. They are far more numerous and are abundant on palms, soles of feet and forehead. Apocrine Sweat Gland A smooth muscle attached to hair follicles that causes "goose bumps" to appear on the skin when contracted. 5