Question | Answer |
EPIDERMIS | The most superficial layer of the skin; consists of epithelial tissue. |
DERMIS | "True skin"; made of connective tissue; provides most of the structural support for the skin. |
HYPODERMIS | Loose connective tissue; not a true integumentary structure; attaches skin to the muscles; subcutaneous tissue. |
KERATINOCYTES | Main epidermal skin type; produces keratin; resists abrasion and reduces water loss. |
MELANOCYTES | Produce melanin; which contribute to skin color. |
LANGERHANS CELLS | Cells in the epidermis that are part of the immune system. |
MERKEL CELLS | Specialized epidermal cells associated with nerve endings responsible for detecting light touch and superficail pressure. |
DESQUAMATE | Slough off; most superificial epidermal cells |
KERATINIZATION | The process that occurs in the epidermis where older cells become harder and are pushed to |
STRATA | Regions or layers |
STRATUM BASALE | Anchored to basement membrane by hemidesmosomes; deepest layer of epidermis; rapid cell division. Keratinization begins in this layer. |
STRATUM GERMINITIVUM | Another name for the Stratum basale. |
STRATUM SPINOSUM | 8-10 layers of many-sided cells; cells become flattened and break apart; 8-10 cell layers; desmosomes are broken and reformed: cells shrink as they harden; "spiny layer"; cell division slows down and ceases. |
STRATUM GRANULOSUM | 2-5 layers of cells; flattened diamond-shaped cells with long axes parallel to the skin's surface; "grainy layer" due to keratohyalin; cells die in the superficial layers. |
KERATOHYALIN | Nonmembrane-bound protein granules that accumulate in the cytoplasm of the cell. |
STRATUM LUCIDUM | Found only in thick skin; several layers of dead cells; clear zone. |
STRATUM CORNEUM | Most superficial layer of epidermis; 25 or more layers of dead squamous cells joined by desmosomes; cells desquamate. |
CORNIFIED CELLS | Dead cells |
KERATIN | Mixture of keratin fibers and keratohyalin; soft in skin and hard in nails and hair. |
THICK SKIN | Found in areas subject to pressure or friction; palms of hands, the soles of feet, and the fingertips. |
THIN SKIN | Covers most of the bod; missing the stratum lucidum, hairs is found in this part of the skin. |
CALLUS | A thickened area of the stratum corneum resulting from friction or pressure |
CORN | A cone shaped thickened area of the stratum corneum overlying a bony prominence resulting from friction or pressure. |
MELANIN | A group of pigments responsible for for skin, hair, and eye color; protects against UV light. Synthesized from the amino acid tyrosine. |
MELANOSOMES | Vesicles that contain melanin found in melanocytes whose long processes extend into the keratinocytes of the stratum basale. The keratinocytes then phagocytize the tips of the melanocytes arms, thereby ingesting the vesicles and moving the melanin closer |
ALBINISM | A recessive trait caused by the inability to produce the enzyme tyrosinase needed in the production of melanin. Thus these individuals have a deficiency or absence of pigment in their skin, hair, and eyes. |
ERYTHEMA | An increase in blood flow to the surface of the skin which causes redness (blushing). Can be due to infections, sunburn, allergic reactions, insect bites, etc... |
CYANOSIS | A decrease in blood flow such as when shock occurs which makes the skin appear bluish due to lack of oxygen. |
CAROTENE | An orange pigment used in the production of Vitamin A that can accumulate in the stratum corneum and adipose tissue causing the skin to appear yellow or orange. |
DERMAL PAPILLAE | Dermal layer that forms the ridges underlying the epidermis that contain blood vessels to provide it with nourishment, waste removal, and temperature regulation; in thick skin, the dermal papillae form the fingerprints and footprints which increase fricti |
RETICULAR LAYER | Inferior portion of the dermis which connects to the hypodermis; forms our cleavage lines which are important in scar formation. [See page 157, Figure 5.5] |
STRIAE | Stretch marks caused by rupture of the dermis from skin stretching. |
SUPERFICIAL FASCIA | Another name for the hypodermis or subcutaneous tissue. Supplies the underlying bones and muscles with nourishment. Where most adipose tissue is found. |