ANP 1106 Lecture Notes - Lecture 2: Adipose Tissue, Hemoglobin, Epithelial Root Sheath
Document Summary
Comprised of the skin and its accessory structures (glands, hairs, and nails) Cutane/o, dermat/o, derm/o relating to the skin. 2 distinct layers: epidermis: outermost layer, composed of epithelial cells, avascular, dermis: middle layer, leathery, fibrous connective tissue, everything happens in this layer. Sits on top of the hypodermis, which is not actually a part of the skin subcutaneous: connects the other layers to the underlying tissues. Cell types: same as in ct: fibroblasts, macrophages, wbcs, some mast cells. Semi-fluid matrix with collagen, elastin, and reticular fibres. Has arrector pili muscles: makes hairs stand up and causes goosebumps. Layers: papillary layer: thin, superficial interwoven mate of ct fibers interspersed with blood vessels, has a wavy border to connect it to the epidermis helps provide stability. Indents the overlying epidermis: reticular layer: deeper, thick, dense irregular ct, source of cleavage/tension lines, the collagen fibers that form this layer give strength and elasticity and maintain skin hydration, the elastic fibers provide stretch-recoil.