Chapter 6 Integumentary System

QOD #1/Pre-Quiz 1. T/F The integumentary system only refers to your skin. 2. T/F Your skin contains a waterproofing protein. 3. T/F Your skin has nothing to do with homeostasis. 4. T/F The integumentary system has 4 layers. 5. T/F There is a disorder in which a person grows hair excessively all over their body (werewolves).

Pre-Quiz cont.. 6. An infected hair follicle is called a A. boil B. mole. C. acne. D. callous. 7. Thickened area caused by excessive rubbing or pressure. 8. A fleshy skin tumor. 9. Overactive and inflammation of the sebaceous (oil) glands.

Integumentary System Membranes of epithelium and connective tissues that cover body surfaces and lines cavities and organs. 2 or more tissues grouped together = organs 4 Membranes Serous Mucous Synovial Cutaneous (skin)

4 membranes SEROUS Lines body cavities that lack openings to the outside Paritel pleura, parietal peritoneum, visceral pleura, visceral peritoneum Contains simple squamous epithelial and loose connective tissue Serous cells secrete serous fluid to lubricate

4 membranes MUCOUS Lines cavities that open to outside of body Oral & nasal cavities, digestive, respiratory, urinary, reproductive Contains epithelium and loose connective tissue Mucous cells secrete mucus

4 membranes SYNOVIAL Inner linings of joint cavities, between ends of bones, and freely movable joints Knees, shoulder, phalanges Contains loose connective tissue & adipose Synovial cells secrete a thick, colorless synovial fluid that lubricate the ends of bones.

4 membranes CUTANEOUS (SKIN) Largest and very versatile organ Vital in maintaining homeostasis Regulates body temperature Limits water loss Houses sensory receptors Synthesizes various biochemicals Excretes wastes 2 .5layers Epidermis Dermis Subcutaneous Basement membrane separates these layers

SKIN EPIDERMIS Outer layer of stratified squamous Keratinization: older cells harden, cytoplasm fills with strands of tough, fibrous, keratin-waterproof protein (stratum corneum) Stratum corneum -avascular, old, hard, dead cells Stratum basale -blood supply from dermis-cells grow and divide and move (pushed) up

Epidermis cont.. The growth and loss of cells is balanced Cell reproduction increases where skin is rubbed or pressed regularly, causing thickened areas called calluses. Functions (protective) Shields underlying tissues from water loss Mechanical injury Harmful chemicals Keeps out disease

Epidermis cont… Contains melanocytes that produce melanin Absorbs light energy to protect deeper cells from U-V damage-dark pigment. Produces skin color Amount of melanin produced and size of granules determines how light/dark your skin is, as well as: -genetics -sunlight (U-V) -blood in surface vessels (high O2 = pink low O2 = blue –cyanosis)

DERMIS Inner layer that contains fibrous connective tissue, epithelial smooth, nervous, and blood tissues Thicker Tough & elastic (due to collagen & elastic fibers) Contains blood vessels Give nutrients to all skin cells and regulates body temp (if hot b.v expand to release heat, if cold b.v contsrict to keep heat in) Bed sores Contains nerve fibers, hair follicles, sebaceous glands, and sweat glands

SUBCUTANEOUS (hypodermis) Beneath dermis/continuous from Contains loose connective tissue and adipose Insulates Binds skin to underlying organs

ACCESSORY ORGANS Hair follicles Hair is dead epidermal cells (keratinized) ) Arrector pili muscle attached to hair follicle Contracts in cold or upset (goosebumps) Color from melanin More=darker None=albinism Trichosiderin=red shaft Hair follicle Cell division occurs here

Congential generalized hypertrichosis-”werewolves”

Sebaceous Glands Attached to hair follicles Holocrine gland Secrete oily mixture of fat and sebum (cell debris) Keeps hair and skin soft, pliable and waterproof * Acne: overactive and inflamed sebaceous gland

Nails Keratinized stratified squamous epithelial with hard keratin Lunula is the growing region.

Sweat Glands (sudoriferous) Sweat=water, salt, waste (urea & uric acid) Apocrine gland (emotional) Armpit and groin Exocrine gland (hair follicles) Palms and soles of feet Eccrine gland (heat and exercise) Forehead, neck, back