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”• 1st degree – minor discomfort – reddening of skin

– only epidermis• 2nd degree – deep epidermal and some , dermal –

blistering, damage sweat glands, oil glands, hair• 3rd – complete destruction of the dermis –

insensitive to pain.

1st Degree• 1st degree – minor discomfort – reddening of skin –

only epidermis

2nd Degree• 2nd degree – deep epidermal and some ,

dermal – blistering, damage sweat glands, oil glands, hair

3rd Degree• 3rd – complete destruction of the dermis –

insensitive to pain. Scarring and lesions