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. 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

5. 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

6. 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

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

8. 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)

9. 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

10. 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

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

12. 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

13. 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”

14. 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

15. 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

16. 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

17. 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

18. 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

19. DIAGNOSIS - ABCs
A) Asymmetry- sides of the pigmented spot or mole do not match B) 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