Integumentary System

1. Integumentary System Cover & Protect

2. Functions of the Skin • PROTECTS - from injury, chemicals, temperature, & bacteria • PREVENTS water loss by producing keratin – a water proofing protein • REGULATES body temperature • EXCRETES excess wastes • PRODUCES Vitamin D • PROVIDE information about our environment

3. Epidermis - the outer layers of the skin made up of stratified squamous epithelium that is capable of keratinizing Dermis - deep layer of the skin; composed of dense, irregular connective tissue. subcutaneous tissue, or hypodermis - adipose tissue anchor the skin to underlying organs

4. STRUCTURE OF THE EPIDERMIS • COMPOSED OF FIVE LAYERS (STRATA) • Stratum corneum • Stratum lucidum • Stratum granulosum • Stratum spinosum • Stratum basale

5. Structures of the Epidermis • STRATUM BASALE - deepest cell layer of the epidermis - connected to dermis along a wavy borderline that resembles corrugated cardboard - contains epidermal cells that receive the most adequate nourishment - millions of new cells are produced daily

6. Structures of the Epidermis • STRATUM SPINOSUM & STRATUM GRANULOSUM - Cells become increasingly flat and full of keratin – water-proofing protein • STRATUM LUCIDUM • Layer in which cells die- only found where skin is hairless and extra thick - the palms of the hands and soles of the feet

7. Structures of the Epidermis • STRATUM CORNEUM (outermost layer) • 20 to 30 cell layers thick • Cells are completely filled with keratin • Creates hard layer that protects cells underneath • Average person loses 18 kg (40 lb) of this layer in their lifetime • Replaced by cells of stratum basale every 25 to 45 days

8. MELANOCYTES • a cell that produces melanin • Melanin - dark pigment responsible for skin color

9. MELANOCYTES • Specialized cells found primarily in the stratum basale • Produce the pigment known as MELANIN – ranges in color from yellow to brown to black • Production is stimulated by sunlight • Freckles and moles are seen where melanin is concentrated in one area. Melanin production is genetically determined.

10. Structures of the Dermis • PAPILLARY LAYER • Upper dermal region that is uneven • Has projections called dermal papillae which indent the epidermis above • Papillae of hands and feet are arranged in definite patterns – these form looped and whorled ridges • Layer that houses touch (Meissner’s corpuscles) and pain receptors (free nerve endings)

11. Structures of the Dermis • RETICULAR LAYER • Deepest skin layer • Contains blood vessels, sweat and oil glands • Has deep pressure receptors called Pacinian corpuscles • Contains collagen fibers which gives the skin its strength • Contains elastic fibers which give skin elasticity when we are young

12. SKIN PIGMENTS • Amount and kind of melanin – ranges from yellow to brown to black • Amount of carotene – a yellow-orange pigment found in foods like carrots – the body deposits it in stratum corneum and subcutaneous layer • Amount of oxygen-rich hemoglobin – blood pigment that shows through from the dermal capillaries

13. SKIN APPENDAGES • SEBACEOUS GLANDS • Produces oils (sebum) that keep skin moist and soft • Prevents hair from becoming brittle • Sebum contains chemicals that kill bacteria

14. SKIN APPENDAGES • SWEAT (SUDORIFEROUS) GLANDS • ECCRINE - numerous and are found all over the body; produce sweat; important and highly efficient part of the body’s heat-regulating equipment • APOCRINE - confined to the axillary and genital areas of the body; usually larger; ducts empty into hair follicles

15. SKIN APPENDAGES • HAIR • Produced by an epithelial structure called the hair follicle • Composed of three layers: medulla (inner layer), cortex (middle layer) & cuticle (outer layer) • The cuticle is formed by highly keratinized, dead epithelial cells • The arrector pili muscle attached to the hair follicle are the cause of “goose bumps”

16. SKIN APPENDAGES • NAILS • Modifications in the epidermis having free edge, nody (visible attached portion) and root (embedded in skin) • Heavily keratinized and colorless – appear pink because of blood supply below • Grows from the nail bed or matrix

17. BURNS • BURN – damage or cell death caused by intense heat • 1st Degree - only the epidermis is damaged; area is red and swollen; generally heal in two to three days; Sunburn • 2nd Degree - injury to the epidermis and the upper region of the dermis; skin is red and painful, and blisters appear • 3rd Degree - destroy the entire thickness of the skin; blanched (gray-white) or blackened

18. SKIN DISORDERS • ATHLETE’S FOOT – itchy, red, peeling condition between toes – caused by a fungus • COLD SORES – fluid filled blisters that itch & sting – caused by herpes simplex infection- activated by upset, fever or UV light • PSORIASIS – chronic condition producing too many skin cells – believed to be an autoimmune disorder in which the immune system attacks a person’s own tissues

19. SKIN DISORDERS • ACNE – condition caused by the overproduction in the hair follicles – prevalent in teens because of hormonal changes • Basal Cell Carcinoma – most common skin cancer – appear as lesions in areas that have been exposed to a lot of sun – relatively slow growing

20. SKIN DISORDERS • Squamous Cell Carcinoma – appears as a red, scaley lesion – eventually forms an ulcer on the surface of the skin – appear most often on scalp, ears, dorsum of the hands, and lower lip- also believed to be sun-induced • Malignant Melanoma – begins wherever there is pigment – appears spontaneously or where there is existing pigment

21. DIAGNOSIS - ABCs A) Asymmetry- sides of the pigmented spot or mole do not matchB) Border irregularity - borders of the lesion are not smooth but exhibit indentations.C) Color - pigmented spot contains areas of different colors (blacks, browns, tans, and sometimes blues and reds).D) Diameter - spot is larger than 6 millimeters (mm) in diameter (the size of a pencil eraser). E)Elevation – above skin surface