Exam 3 Flashcards
Epidermis
Keratinized stratified squamous epithelium
Dermis
Dense irregular tissue
Keratinized
Change or become changed into a form containing keratin.
Keratinized
Protects deep tissue from abrasion, found on the sole of the foot and palms of hand.
Non-keratinized
Must be kept moist from bodily secretions to to prevent drying out, found in the lining of the oral cavity, pharynx, esophagus, lining of vagina and anus.
5 Layer of Epidermis/ deep to superficial
Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum (thick only), Stratum Corneum
Stratum Basale/Stratum Germinative/Basal Layer
Deepest layer, single layer of cuboidal to lower columnar cells tightly attached to an underlying basement membrane that separates the epidermis from the connective tissue or adjacent dermis.
Stratum Basale/Stratum Germinativum/Basal Layer Cells
Keratinocytes: dead, divide to generate new cells.
Melanocytes: Alive, produce and store pigment melanin.
Tactile cells/Merkel Cells: Alive, sensitive to touch, when compressed release chemicals that stimulate sensory nerve endings providing info about objects touching skin.
Stratum Spinosum/Spiny Layer
Made up of several layers of polygonal keratinocytes. Each time a keratinocyte stem cell divides, a daughter cell is pushed to the external surface of the Stratum Basale. Once it enters the Stratum Spinosum, it begins to differentiate into non-dividing, highly specialized keratinocyte.
Stratum Spinosum/Spiny Layer Cells
Epidermal Dendritic Cells: Alive, immune cells that help fight infection.
Stratum Granulosum/Granular Layer
Consists of 3-5 layers of keratinocytes superficial to the Stratum Spinosum. Process of Keratinization begins here.
Stratum Granulosum/Granular Layer Cells
Keratinized Cells: Dead, because there is no nucleus or organelles but are structurally strong because of the keratin it contains.
Stratum Lucidum/Clear Layer
Thick skin only, is a thin translucent region of dead skin cells about 2-3 cell layers that is superficial to the Stratum Granulosum. Located on the palms of hands and soles of feet.
Stratum Lucidum/Clear Layer Cells
Keratinocytes that are flattened and filled with translucent protein called eledin. This layer helps protect from UV light.
Stratum Corneum/Hornlike Layer
Is the most superficial layer of the epidermis. Is the Stratum you see when you look at your skin.
Stratum Corneum/Hornlike Layer Cells
20-30 layers of dead, Anucleate cells that are scaly, interlocking keratinized Cells. Functions as a barrier.
Where does keratinization begin?
In the Stratum Granulosum
What are the differences in thick and thin skin?
Thick skin has stratum Lucidum, thin skin does not.
Thick skin
Found on palms of hands and soles of feet and has no hair follicles or oil glands.
Thin Skin
Covers most of the body, and has hair follicles and oil glands.
What combination helps give skin color and tone?
Hemoglobin, melanin, carotene
Albinism
Inherited recessive condition where enzyme needed to produce melanin is non-functional. Individuals have White hair, pale skin, and pink irisis.
Nevus
Commonly called a mole, is a harmless overgrowth of melanocytes.
Freckle
Yellowish or brown spots that represent localized areas of increased melanocyte activity. Degree of pigmentation depends on sun exposure and hereditary.