INTEGUMENTARY SYSTEMOne major organ= skin - outer covering of the body Size= largest organ of the bodyParts (4.2) epidermis- outer most layer stratified squamous epithelium dermis- deep layer dense irregular connective tissue (subcutaneous layer or hypodermis)- not considered a true part of the skin Epidermis- most superficial part of the bodystratified squamous epithelium- several layers deep and has flat cells on top- grows from the deep layer to the surface, the outermost skin cells are dead keratin- waxy protein Properties:1. waterproof due to keratin 2. Dead cells are designed to wear away 3. melanin- dark brown or black pigment; material that makes skin darker; function is to block ultra violet rays- which damage chromosomesDermis- thick layer of dense irregular connective tissueFibers- protection- resists tears/ puncture collagen and elastin blood supply- rich blood supply sensation/tactile- nerve endings- sense of touch Subcutaneous tissue- loose connective and adipose tissue; attaches skin to muscles underneath it;this is where we tend to accumulate fatfibers- adipose tissueACCESSORY STRUCTURESHair (4.9) shaft- the part we see on the surface, exposed tip of the hairroot- extends from the hair bulb root sheath- this layer extends from the skin surface to the hair matrix hair papilla- peg of connective tissue containing capillaries and nervesarrector pili- smooth muscle that extends from the papillary dermis to the connective tissue sheath surrounding the hair follicle bulb- epithelial cells that surround surround the papillagrowth (4.11)- a hair in the scalp grows for 2-5 years at a rate of .33mm/day; deep cells divide and this pushes them towards the scalp where they fill with keratin and die color- depends on environmental or hormonal factors whether it black or brown depends of the density of the melanin in the cortex distributionINTEGUMENTARY SYSTEM page 2Glandseccrine = merocrine- sweat glands that are more numerous than apocrine sweat glands; palmsand soles have the highest number and they are coiled and tubular sebaceous- oil glands, discharge a waxy, oily secretion into hair follicles others- mammary glands found in the breasts and ceruminous glands are modified sweat glands found in the external auditory canal they produce ear wax Nails (4.15) growth- grows from the nail root and gets pushed towards the end of the nail, fills with keratin and diesmatrix (root)- where nail production occurs eponychium- cuticle lunula- under the nail near the root blood vessels maybe obscured leaving a pail crescent body- covers the nail bed nail bed- underneath the nail body FUNCTIONS OF SKIN1. Water proofing- protects against water loss2. Protects against pathogens3. Protects against UV rays 4.Temperature regulation (sweating vasodilation) 5. Vitamin D production6. Mechanical protection 7. Sense of touch(sense
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