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

• Avascular

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• Nerve Fibers• Pacinian Corpuscle – deep in dermis – detects pressure• Meissner’s Corpuscle – shallow in dermis-located toward

the epidermal base – detect light touch• Free nerve endings – detect pain• Krause’s end bulbs – detect vibrations

Nails - Appendage• Filled with Keratin

• Nail Root – nail underneath skin

• Cuticle – groove where skin meets nail

• Lunula – “little white moon”• Low Oxygen = cyanosis – blue color

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