1. The Integumentary System

2. Review of membranes Types of membranes 1. serous ◦ line body cavities that do not open to the outside  visceral – covers the organ  parietal – covers the cavity ◦ made up of epithelium and loose connective tissue ◦ secrete serous fluid for lubrication

3. Serous membrane

4. Types of membranes 2. mucous ◦ line cavities with openings to the outside  oral and nasal cavities  openings of digestive, reproductive, respiratory, and urinary systems ◦ made up of epithelium on loose connective tissue ◦ contain goblet cells to secrete mucus

5. mucous membranes of stomach

6. Types of membranes 3. synovial ◦ line joint cavities ◦ consist only of connective tissues ◦ secrete lubricating synovial fluid 4. cutaneous membrane - skin

7. Synovial membrane

8. Cutaneous membrane

9. The Integumentary System integumentary = covering composed of skin, sweat and oil glands, hair, nails mini-excretory system ◦ removes urea, salts, water through sweat large organ composed of 3 distinct layers ◦ epidermis ◦ dermis ◦ hypodermis

11. Functions of Integumentary System 1. protection from abrasion, uv radiation, keeps out bacteria/viruses and prevents water loss 2. sensation of heat, cold, touch, pressure, pain 3. vitamin D production 4. temperature regulation 5. excretion of wastes

12. Epidermis outermost layer composed mostly of keratinized stratified squamous epithelium avascular composed of 4-5 layers grow new epidermis every 25-45 days

13. layers of epidermis 1. stratum basale – layer of reproducing cells at base of epidermis ◦ cuboidal or columnar cells ◦ nourished by blood vessels of dermis ◦ millions of cells produced daily ◦ push older cells to surface where they become keratinized  resist abrasion, produce permeability barrier

14. layers of epidermis 2. stratum spinosum 3. stratum granulosum 4. stratum corneum ◦ most superficial ◦ dead, squamous cells filled with keratin ◦ 25 or more layers thick ◦ areas subjected friction form calluses * stratum lucidum (palms and soles)

16. skin color melanocytes: cells in stratum basale ◦ produce melanin  yellow to brown to black  protects cells from uv radiation  freckles and moles – melanin concentrated in one spot  Racial differences determined by amount, kind and distribution of melanin.

17. skin color cyanosis (bluish colored skin) ◦ caused by low oxygen in blood redness ◦ blushing, fever, hypertension, inflammation, allergy pallor ◦ fear, anger, anemia, low blood pressure, impaired blood flow

18. skin color jaundice ◦ liver disorders, excessive bile bruises ◦ blood clotted in tissue spaces (hemotoma) ◦ unusual bruises: low vitamin C, hemophilia albinism ◦ recessive genetic trait ◦ deficiency of melanin ◦ fair skin, white hair, unpigmented irises

19. Dermis made mostly of connective tissue ◦ collagen, elastic fibers  Collagen is directional; causes stress lines. binds epidermis to underlying tissue vascular, carry nutrients to upper layers and regulate temperature

20. Dermis 2 layers dermal papillae ◦ nerve fibers, sensory fibers (Meissner corpuscles), hair follicles Dermal Papillae are projections from the dermal layer into the epidermal layer. ◦ help to deliver oxygen/nutrients from the vascular system to the epidermal layer

22. dermal papillae

23. Meissner corpuscles

24. Dermis reticular layer ◦ deepest skin layer ◦ blood vessels, sweat and oil glands, deep pressure receptors (Pacinian corpuscles)

26. Hypodermis subcutaneous layer loose connective and adipose tissues not part of the skin; base layer it rests upon attaches skin to underlying organs contains blood vessels that supply the skin no real boundary between dermis and subcutaneous layers stores fat for padding and insulation

27. Accessory organs of the skin 1. Hair extension of epidermis deep into dermis found over most of human body ◦ mostly useless produced in hair bulb which rests on dermal papillae columns of keratinized epithelial cells ◦ continues to grow as new cells are added at the roo t

28. Hair Parts of the hair shaft – above surface of skin ◦ Medulla – soft center ◦ Cortex - hard ◦ Cuticle – outer covering  single layer of overlapping cells that holds hair in follicle root – part of hair in follicle hair follicle – below surface of skin

29. hair hair bulb – base of follicle  where hair grows  cell division – living cells  push up and become keratinized arrector pili – small bands of smooth muscle  connect each side of hair follicle to dermal layer  contraction – goose bumps

31. arrector pili

32. hair color genetic trait melanin in hair bulb fades with age no melanin = white hair

33. Accessory structures 2. Nails thin plate; keratinized stratum corneum cells parts of nail ◦ free edge ◦ nail body (part that is seen) ◦ nail root – covered by skin ◦ nail matrix – gives rise to cells that form nail  lunula – whitish crescent at base of nail ◦ nail bed – place of attachment ◦ cuticle – stratum corneum on nail body

37. Accessory organs of skin 3. Sebaceous glands simple, branched grape-like gland connected by duct to superficial part of follicle not on palms or soles produce sebum – oily, lipid-rich ◦ lubricates hair and surface of skin ◦ waterproofs and moisturizes ◦ kills bacteria ◦ whiteheads/blackheads – blocked glands ◦ acne – infected glands

39. Accessory organs of skin 4. Sweat glands – two types merocrine ◦ simple, coiled gland ◦ located in all areas of skin ◦ most numerous in palms, soles ◦ respond to body temperature ◦ secrete water and some salts ◦ open to surface of skin via sweat pores ◦ Sweat on skin cools body.

40. Accessory organs of skin apocrine ◦ simple, coiled, tubular gland ◦ Secretions are thick and organic.  broken down by bacteria to produce body odor ◦ open into hair follicles of axillary and genital areas ◦ become active at puberty modified sweat glands ◦ ceruminous – produce earwax ◦ mammary – produce milk