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integumentary ard
integumentary system
Question | Answer |
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the hypodermis is subcutaneous tissue beneath the skinn consisting mostly of | adipose tissue that anchors the skin to the underlying muscle, allows skin to slide over muscle |
epidermis is a | keratinized stratified squamous epithelium |
cells of the epidermis | the majority of epidermal cells are keratinocytes that produce keratin. melanocytes are epithelial cells that synthesize the pigment melanin |
layers of the epidermis | the stratum basale (basal layer) is the deepest epidemal layer and is the site of mitosis the stratum corneum(horny layer) is the outermost protective layer of the epidermis composed of a thick layer of dead keratinocytes |
dermis is composed of strong, flexible, connective tissue | the dermis is made up of two layers: the thin, superficial papillary layer is highly vascularized areolar connective tissue containing a woven mat of collagen and elastin fibers; and the reticular layer, accounting for 80% of the thickness of the |
accounting for 80% of the thickness of the dermis, is dense irregular connective tissue | skin color is determined by three pigment:melanin, hemoglobin, and carotene |
sweat | secretion by sebaceous glands is stimulated by hormones |
hairs, or pili, are flexible strands produced by follicles that consist of dead, keratinized cells | the main regions of hair are the shaft and the root |
a hair has three layers of keratinized cells: | the inner core is the medulla, the middle layer is the cortex, and the outer layer is the cuticle |
hair pigments(melanin of different colors)are made by | melanocytes at the base of the hair follicle. |
hair follicles fold down from the epidermis into the dermis and occasionallly into the hypodermis | the deep end of a hair follicle is expanded, forming a hair bulb |
the wall of a hair follicle is compose of an outer connective tissue root sheath, a thikened basement membrane called a glossy membrane, and an inner epithelial root sheeth | associated with each hair follicle is a bundle of smooth muscle cells called an arrector pili muscle |