Integumentary System and Body Membranes The Skin and its appendages – hair, nails, and skin glands Anatomy/Physiology - NHS

Body Membranes Sheet-like layer covers and/or lines – hollow organs, body cavities etc.. Cutaneous – SKIN Serous – covers organs, lines cavities, and secretes a thin watery fluid – lubricate, reduce friction Mucous – Secrete mucus to exterior surface, lines the RT, GIT, and UG – keeps moist and soft

Body Membranes (Connective) Do not have epithelial components Smooth Slick Coverings of Joints Secrete Synovial Fluid - lubricates – reduces friction

SKIN – Cutaneous Membrane Largest Organ Also called Cutaneous Membrane Membranes – cover/protect body surfaces – line body cavities and cover the insides of hollow organs 16% of body weight

Epidermis Outer layer of skin Several stratified squamous – thin Tightly Packed Produces Keratin- tough water proof material – used for protection Produces Melanin – pigment of skin Avsacular

Dermis Deep layer of skin loosely packed Mostly connective tissue Dermal Papillae – parallel rows or peg like projections Vascular Form Ridges Sensory

Hair - Appendage Follicles in dermis produce hair –papilla from birth Papilla is nourished by blood vessels Roots and Shafts make up hair Lunago – newborns hair Arrector pilli cause “Goose Bumps”

Receptors - Appendage Myelinated Nerve Fibers Pacinian Corpuscle – deep in dermis – detects pressure Meissner’s Corpuscle – located toward the skin surface – light touch Free nerve endings – pain Krause’s end bulbs – detect low frequency vibrations

Nails - Appendage Filled with Keratin Nail Root – nail underneath skin Cuticle – groove where skin meets nail Lunula – “little white moon” Low Oxygen = cyanosis – capillary refill

Skin Glands Sweat (Sudoriferous) Glands – most numerous – produce perspiration – excrete waste such as ammonia and uric acid, help maintain body temp Sebaceous gland – secretes oil for hair and skin

FUNCTION - Protection PROTECTION:Melanin protects from U.V. rays, Keratin is waterproof and microproof Temp. Regulation: Removes up to 3,000 calories of heat a day Sensing: Senses Pain, Hot Cold, Touch - Millions of “antenna”

Burns Causes: UV Light, Fire, Electricity, Acid Total area involved – “rules of nine” 1 st degree – minor discomfort – reddening of skin – only epidermis 2 nd degree – deep epidermal and some, dermal – blistering, damage sweat glands, oil glands, hair 3 rd – complete destruction of the dermis – insensitive to pain.

1 st Degree 1 st degree – minor discomfort – reddening of skin – only epidermis

2 nd Degree 2 nd degree – deep epidermal and some, dermal – blistering, damage sweat glands, oil glands, hair

3 rd Degree 3 rd – complete destruction of the dermis – insensitive to pain. Scarring and lesions