Chapter 6
organ - ANStwo or more kinds of tissues grouped together and performing specialized functions
Integumentary system function - ANS- composed of several tissue types
- maintains homeostasis
- protective covering
- retards water loss
- regulates body temperature
- houses sensory receptors
- contains immune system cells
- synthesizes chemicals
- excretes small amounts of wastes
Epidermis - ANS- outer layer
- stratified squamous epithelium
dermis - ANS- inner layer
- contains collagenous and elastic fibers
subcutaneous layer (hypodermis) - ANS- beneath dermis
- areolar and adipose C.T
Epidermis - ANS- stratified squamous epithelium
- keratinized
- rests on basement membrane
- lacks blood vessels
- melanocytes provide melanin
Epidermis thickest - ANSon palms and soles (0.8-1.4mm)
Five layers of epidermis (top to bottom) - ANS- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
Stratum corneum - ANSdead keratinized cells
Stratum lucidum - ANSonly in thick skin-palms, soles
, Stratum basale - ANSmitotic layer
keratinization - ANSprocess that happens as cells move up from basement layer - drying out
Melanocytes - ANS- located in the stratum basale
- produce the dark pigment melanin
Melanin - ANS- gives skin color
- also absorbs UV light
Genetic factors that affect skin color - ANS- varying amounts of melanin
- varying size of melanin granules
- albino lack melanin
Environmental factors that affect skin color - ANS- sunlight
- UV light from sunlamps
- x-rays
Physiological factors that affect skin color - ANS- dilation of dermal blood vessels (blush)
- constriction of dermal blood vessels (cold, shock, sick)
- accumulation of carotene (pigment in plants)
- jaundice
Dermis two layers - ANSPapillary layer
Reticular layer
Papillary layer - ANS- areolar
- thin
- superficial
- dermal papillae
Reticular layer - ANS- dense irregular C.T.
- most of dermis
Dermal papillae - ANS- extend into spaces between epidermal ridges
- form fingerprints
- genes determine pattern
Dermis - ANS- on average 1-2 mm thick
- binds epidermis to underlying tissues
- dense irregular connective tissue
- muscle cells
- nerve cells processes