BIOS 251 Exam 3 Questions and Answers Top Graded Chamberlain University

integumentary system - consists of the skin, hair, nails, and their associated glands epidermis - -outermost layer of skin -keratinized stratified squamous epithelium -surface consists of dead cells packed with keratin -lacks blood vessels and depends on the diffusion of nutrients from the underlying connective tissue -sparse nerve ending for touch and pain dermis - -middle layer of skin, deeper connective tissue layer -consists of mainly collagen, but also has elastic and reticular fibers, fibroblasts, and other fibrous connective tissues -well supplied with blood vessels, glands, and nerve endings -hair follicles and nail roots Hypodermis - -loose connective tissue layer of skin -bottom layer -subcutaneous tissue -areolar and adispose tissue -pads body and binds skin to underlying tissue -vascular, drugs inserted here -has subcutaneous fat for insulation and an energy resovior thick skin - covers the palms, soles, and corresponding surfaces of the fingers and toes. has sweat glands but no hair follicles or sebaceous (oil) glands thin skin - has an epidermis about 0.1 mm thick, with a thin stratum corneum. possesses hair follicles, sebaceous glands, and sweat glands. functions of skin - resistance to trauma and infection, other barrier functions, vitamin D synthesis, sensation, thermoregulation, nonverbal communication keratinocytes - -majority of epidermal cells -synthesizes keratin -produced deep in the epidermis by the mitosis of stem cells in the stratum basale stem cells - -cells that divide and give rise to the keratinocyes -found in stratum basale melanocytes - -occur only in stratum basale -synthesize the brown to black pigment melanin tactile cells - -receptors for touch -in stratum basale dentritic cells - -found in stratum spinosum and stratum granulosum -immune cells that originate in the bone marrow but migrate to the epidermis and epithelia of the oral cavity, esophagus, and vagina -stand guard against toxins, microbes, and other pathogens that penetrate into the skin -alert immune system to invaders stratum basale - -5th and deepest layer of epidermis -consists of a single layer of cuboidal to low columnar stem cells -has keratinocytes, melanocytes, tactile cells, and stem cells stratum spinosum - -4th layer of epidermis -several layers of keratinocytes -usually thickest stratum -dendritic cells too stratum granulosum - -3rd layer of epidermis -3 to 5 layers of flat keratinocytes -contain keratohyalin granules stratum lucidum - -2nd layer of epidermis -keratinocytes are densely packed with a clear protein named eleidin -pale, featureless appearance with indistinct cell boundaries stratum corneum - -1st layer of epidermis -consists of up to 30 layers of dead, scaly, keratinized cells that form a durable surface layer -resistant to abrasion, penetration, and water loss papillary layer - -outer layer of the dermis, directly beneath the epidermis -thin zone of areolar tissue in and near the dermal papilla -rich in small blood vessels reticular layer - -Deeper layer of the dermis that supplies the skin with oxygen and nutrients -thicker than other layer -dense irregular connective tissue, tougher than papillary layer melanin - -A pigment that gives the skin its color -produced by melanocyes eumelanin - brownish black pigment Pheomelanin - a reddish yellow sulfur-containing pigment Carotene - -yellow pigment acquired from egg yolks and yellow and orange vegetables -can give yellowish pigment of skin hemangiomas - -birthmarks -patches of skin discolored by benign tumors of the blood capillaries freckles - flat melanized patches that vary with heredity and exposure to the sun mole - -elevated patch of melanized skin, often with hair -harmless and sometimes even regarded as "beauty marks" pilus - hair slender filament of keratinized cells hair follicle - an oblique tube in the skin shaft - portion of hair above skin surface root - hair beneath the surface bulb - where hair originates