Chapter 5 Flashcards
Integumentary System
Body’s first defense against bacteria and injury.
Epidermis
Superficial layer of skin, avascular and protective.
Dermis
Layer beneath epidermis containing blood vessels and receptors.
Subcutaneous Layer
Loose connective tissue below the dermis.
Melanocytes
Cells producing melanin, affecting skin color.
Vitamin D3
Synthesized in skin, essential for calcium metabolism.
Keratinocytes
Most abundant cells in epidermis, produce keratin.
Stratum Basale
Deepest epidermal layer, contains stem cells.
Stratum Spinosum
Layer with spiny keratinocytes and dendritic cells.
Stratum Granulosum
Layer where keratin fibers develop and cells die.
Stratum Lucidum
Clear layer found only in thick skin.
Stratum Corneum
Outer layer of dead keratinized cells.
Accessory Structures
Includes hair, nails, and glands in skin.
Thermoregulation
Process of maintaining body temperature through skin.
Exocrine Glands
Glands in skin that secrete substances externally.
Papillary Layer
Upper layer of dermis, contains sensory receptors.
Reticular Layer
Deeper dermis layer, provides strength and elasticity.
Dendritic Cells
Immune cells in skin, protect against pathogens.
Sebaceous Glands
Glands that secrete oil to lubricate skin.
Sweat Glands
Glands that produce sweat for thermoregulation.
Hair Follicles
Structures that produce hair, involved in sensation.
Arrector Pili Muscle
Muscle that causes hair to stand up.
Tactile Cells
Sensory cells in stratum basale, detect touch.
Cutaneous Membrane
Another term for skin, includes epidermis and dermis.
Skin Color Variation
Differences due to melanin production and sunlight.
Skin Repair Mechanisms
Processes that allow skin to heal after injury.
Sensory Receptors
Cells in skin that detect touch, pressure, pain.
Stratum granulosum
The ‘granular layer’ consisting of 3-5 layers of keratinocytes
Keratohyalin
A protein that forms dense granules, promotes cellular dehydration and cross-linking of keratin fibers
Stratum lucidum
The ‘clear layer’ found only in thick skin, covering stratum granulosum with flattened, densely packed cells
Stratum corneum
The ‘horny layer’ that is the exposed surface of thick and thin skin, water resistant with 15 to 30 layers of keratinized cells
Keratinization
The formation of protective layers of cells filled with keratin, where new cells move from stratum basale to stratum corneum in 7 to 10 days
Epidermal growth factor (EGF)
Produced by salivary glands and glands of duodenum, used in laboratories to grow skin grafts
Functions of EGF
Promotes division of basal cells, accelerates keratin production, stimulates epidermal repair, and stimulates glandular secretion
Papillary layer
Outer layer of the dermis consisting of areolar tissue, containing capillaries, lymphatic vessels, and sensory neurons
Reticular layer
Consists of dense irregular connective tissue, containing collagen and elastic fibers, blood & lymph vessels, and nerve fibers
Dermal strength and elasticity
Provided by collagen fibers that resist stretching and elastic fibers that permit stretching and then recoil to original length
Skin turgor
Measure of elasticity and firmness used to indicate fluid loss or dehydration, influenced by malnutrition, aging, UV radiation
Tension lines (cleavage lines)
Produced by parallel bundles of collagen and elastic fibers in the dermis, affecting healing and scarring of cuts
Dermal blood supply
Includes cutaneous plexus, a deep network of arteries along the reticular layer, and subpapillary plexus, a network of small arteries in the papillary layer
Contusion (bruise)
Trauma to the skin causing dermal blood vessels to rupture, leading to blood leaking into the dermis and resulting in a blue/black color
Innervation of skin
Nerve fibers in skin that control blood flow, adjust gland secretion rates, and monitor sensory receptors
Sensory receptors
Respond to light touch (tactile corpuscles) and deep pressure and vibration (lamellar corpuscles)
Subcutaneous layer (hypodermis)
Connects the dermis to underlying tissues, stabilizing the position of the skin and primarily composed of adipose tissue
Skin Color
Influenced by two pigments in the epidermis: melanin and carotene
Melanin
Red-yellow or brown-black pigment produced by melanocytes, protecting skin from ultraviolet (UV) radiation
Carotene
Orange-yellow pigment found in orange vegetables, accumulates in epidermal cells and can be converted to vitamin A
Blood flow and oxygenation
Influence skin color; hemoglobin is bright red when bound to oxygen and can cause cyanosis when oxygen levels are low
Accessory structures of the integument
Include hair, hair follicles, sebaceous glands, sweat glands, and nails
Hair
Composed of keratinized dead cells; the hair shaft is nonliving and above the skin surface while the hair follicle is living and located under the skin
Hair follicles
Structures producing nonliving hairs in skin.
Root hair plexus
Sensory nerve network surrounding hair follicles.
Arrector pili muscle
Smooth muscle causing hair to stand up.
Goose bumps
Skin reaction from arrector pili contraction.
Hair root
Anchors hair into the skin.
Hair shaft
Upper visible part of the hair.
Sebaceous glands
Oil glands discharging sebum into hair follicles.
Holocrine glands
Glands releasing entire cells with secretion.
Sebum
Lipid secretion lubricating and protecting hair.
Apocrine sweat glands
Glands producing odoriferous secretions.
Merocrine sweat glands
Glands discharging sweat directly onto skin.
Sensible perspiration
Visible sweat aiding in body temperature regulation.
Epidermal fold
Skin structure where nail production occurs.
Nail body
Visible part of the nail covering nail bed.
Eponychium
Cuticle area near the nail root.
Lunula
Pale crescent shape at the nail base.
Mast cells
Cells triggering inflammatory response post-injury.
Granulation tissue
New connective tissue formed during healing.
Keloid
Raised scar tissue formed after healing.
Homeostasis
Stable internal environment maintained by body.
Integumentary system functions
Protects, regulates temperature, synthesizes vitamin D.
Excretion
Removal of salts, water, and wastes through skin.
Immune response
Coordination against pathogens and skin cancers.
