skin (integument) external body covering functions insulation protects prevents water loss...

Skin (Integument) External body covering Functions

Insulation Protects Prevents water loss Temperature regulator Vitamin D Senses

Layers Epidermis, dermis

EpidermisStratum corneum-dead cellsStratum lucidum -thin layer of flat,

dead keratinocytesStratum granulosum -flattened cells;

lamellated granulesStratum spinosum-cells rapidly

dividestratum basale -actively dividing;

contain melanocytes

Dermis Between dermis and subcutaneous layer Dense irregular connective tissue Layers

Papillary layer -areolar connective tissue; fingerprints (epidermal ridges); touch receptors (meissner’s corpuscles)

Dermal papillae-attach dermis to epidermis

Reticular layer -deepest; dense irregular connective tissue; sweat, sebaceous glands, pressure receptors (Pacinian corpuscles)

Hypodermis Below integument Stabilizes Deposits of fat

Protects Protection of openings Sensitive to touch Hair follicle -dense connective tissue sheath;

produces nonliving hair Hair root -lower part of hair; attached to skin Hair shaft -upper part; not attached Arrector pili muscle -muscle attached to hair

follicle

Cutaneous glands Sebaceous glands -lubricates skin (oil and

sweat) Eccrine glands -perspiration Apocrine glands -found in armpits and

genital areas; produce odor