Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
|
2 Parts of the Integumentary System |
-Skin -Associated structures - glands, hair, nails, blood vessels, nerves, & sensory receptors |
|
|
Structure of the skin from superficial to deep |
Epidermis- epithelial tissue Dermis- connective tissue Subcutaneous |
|
|
Epidermis |
Outermost portion of skin. Composed of stratified squamous epithelium; Avascular. Function: protection from wear & tear, injury, & harmful substances. Melanin protects from UV radiation. |
|
|
Epidermal Layers |
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale |
|
|
Stratum Basale |
Deepest Layer. Closest to blood supply, Mitotic, contains melanocytes. |
|
|
Stratum Spinosum |
Spiny projections connect cells, limited Mitotic ability. With stratum Basale forms stratum germinativum. |
|
|
Stratum Granulosum |
Keratinization begins; middle layer |
|
|
Stratum Lucidum |
Only in "thick skin"(palms, fingertips, soles of the feet) |
|
|
Stratum Corneum |
20-30 layers of flat, dead, keratinized cells. About 5 weeks for a cell to move from the stratum Basale to this layer. Cells shed " exfoliate" |
|
|
Keratinization |
Replaces cytoplasm in cell with Keratin - a tough, strong, waterproof protein. |
|
|
Melanocytes |
In the stratum Basale, produce Melanin- a dark pigment that protects skin from sunlight. Activity varies depending on genetics and environment. |
|
|
Keratin |
Tough, water-repellant protein. Prevents water loss by evaporation. |
|
|
Desmosomes |
Areas where keratinocytes attach to each other. |
|
|
Dermis |
Deep to epidermis, 20-40 times thicker than epidermis. Composed of dense irregular connective tissue with elastic fibers (70% fibroblasts- collagen fiber), vascular, contains accessory structures- hair follicles, sebaceous and sudoriferous glands, sensory receptors and blood vessels. Function: protection, nourishment of epidermis, skin elasticity, and sensory perception. |
|
|
2 Regions of the Dermis |
Papillary Layer Reticular Layer |
|
|
Papillary Layer |
Dermal papillae. Is arranged in ridges on hands and feet. Are basis of fingerprints. |
|
|
Reticular Layer |
Blood vessels, sebaceous and sudoriferous glands, deep pressure receptors (Pacinian Corpuscles); phagocytic cells. |
|
|
Subcutaneous Layer (aka hypodermis or superficial fascia) |
Deep to dermis; composed of loose connective tissue- mostly adipose, some areolar, has blood vessels & nerve endings. Connects skin to underlying muscle; insulation, temperature regulation & sensory perception. |
|
|
Accessory Structures of the Skin |
Help protect the skin and give it more function. Includes: sebaceous (oil) glands, sudoriferous (sweat) glands, hair, nails. |
|
|
Sebaceous Glands |
Exocrine glands- ducts open into hair follicle, saclike structure. Produce Sebum- oily secretion that lubricates skin & hair, helps prevent water loss, inhibits bacteria. |
|
|
Vernix Caseosa |
Secretion of sebaceous glands that covers newborn babies. |
|
|
Sudoriferous Glands |
Exocrine glands- coiled, tubular structure. Located in dermis & subcutaneous tissue (primarily in dermis); produces sweat (perspiration) |
|
|
2 Major Classifications of Sudoriferous Glands |
Eccrine Apocrine |
|
|
2 Major Classifications of Sudoriferous Glands |
Eccrine Apocrine |
|
|
Eccrine |
Most numerous, excretory tube opens at a pore on skin surface; sweat contains water & some salts; serve a minor excretory function and helps to control body temp. |
|
|
Apocrine |
Located in Axilla & Groin; become active during puberty, secretes into a hair follicle; sweat contains water, salts & organic compounds; becomes odorous on skin surface. Becomes active with pain, emotional stress & sexual arousal |
|
|
Hair |
Covers almost all of the body. Composed mainly of keratin; non-living. Shaft- portion that projects above skin. Root- the portion below skin |
|
|
Hair follicle |
A sheath of epithelial & connective tissue. Extends through epidermis- mostly in dermis. Builds and encloses hair. Melanocytes in growth region. Most attached to Arrector Pili muscles ("goosebumps", smooth involuntary muscle tissue) |
|
|
Nails |
Protect fingers & toes; help grasp small objects, thin plates of stratum Corneum that contain hard keratin. |
|
|
How does the skin protect against dehydration |
Skin prevents water loss from evaporation with keratin in the epidermis and sebum released from sebaceous glands. Also prevents too much water from entering skin during swimming or bathing. |
|
|
How does it protect from UV radiation |
Melanin absorbs light; melanocytes transfer melanin to skin & hair cells near them; melanin appears as an inclusion in skin cells to protect the DNA. About 1/4 of cells in stratum Basale are melanocytes |
|
|
How does it regulate body temperature |
Activating sweat glands & dilating BVs in dermis cools body down; constricting BVs raises body temp up. |
|
|
How does it collect sensory information |
Skin has many nerve endings and other special receptors: Free nerve endings- no CT, detect pain & changes in temperature Touch receptors- light, discriminating touch (meissner's corpuscles) Deep pressure receptors- (Pacinian's corpuscles) tissue displacement |
|
|
Other activities of skin |
Absorption of substances such as medications. Excretion of water, electrolytes and wastes. Manufacture of Vitamin D- needed for absorption of phosphorus & calcium; synthesized in skin - precursor molecule converted when exposed to small amounts of UV light |
|
|
Color of skin- factors that influence skin color |
Melanin - brown tones Hemoglobin - red tones Carotene - orange tones |
|
|
Free Edge |
Distal edge of nail |
|
|
Nail plate or body |
Visible portion |
|
|
Nail root |
Proximal end, covered with skin |
|
|
Nail bed |
Stratum Basale; deep to nail plate. |
|
|
Nail Matrix |
Proximal portion of nail bed, where growth occurs. |
|
|
Lunula |
Nail plate over matrix |
|
|
Cuticle |
Extension of stratum Corneum over nail root |
|
|
Functions of the integumentary system |
Protection against infection, dehydration and UV radiation, regulation of body temperature, and collection of sensory information. |
|
|
How does the skin protect against infection |
Intact skin forms a primary barrier against invasion; interlocking pattern resists penetration, shedding removes pathogens, secretions protect against bacterial toxins, protects against some harmful environmental chemicals |
