4 Anatomy and Physiology (Marieb 10th edition) Exam|Questions and Answers| 100% Correct

4 Anatomy and Physiology (Marieb 10th edition) Exam|Questions and Answers| 100% Correct outermost protective shield composed of layers of epithelial cells Epidermis makes up bulk of the skin, strong & flexible, tough leathery layer of dense connective tissue dermis subcutaneous tissue just deep to the skin sharing some of the skin's protective functions hypodermis another name for hypodermis superficial fascia most superficial layer; 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin. Glycolipids in extracellular space. stratum corneum clear layer of epidermal layer absent in thin skin; 2-3 layers of clear, flat, dead, keratinocytes with indistinct boundaries. stratum lucidum typically one to 5 layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules (releasing lipids) and keratohyaline granules. stratum granulosum Several layers of keratinocytes unified by desmosomes. Cells contain thick bundles of intermediate filaments made of pre-keratin. stratum spinosum deepest epidermal layer; one row actively mitotic stem cells; some newly formed cells becoming part of more superficial layers. See occasional melanocytes and dendritic cells. AKA - stratum germanitivum stratum basale located in epidermis, chief role is producing keratin, majority of epidermal cells keratinocytes spider shaped epithelial cells that synthesize melanin, found in deepest layer of epidermis melanocytes fibrous protein that gives epidermis protective properties keratin made in skin, polymer of tyrosine amino acids; forms a pigment shield on the sunny-side of keratinocytes that protects from UV radiation. melanin arise from bone marrow to migrate to epidermis, ingest foreign substances and key activators of immune system, aka Langerhans cell dendritic cells a sensory receptor for touch in the epidermis, present at epidermal junction shaped like a spiky hemisphere, and associated with a disc-like nerve ending. tactile cells cells junctions that are "like velcro" connecting cells and producing a tension- resisting network. desmosomes membrane-bound granules that motor proteins along actin fila