The Integumentary System AKA Skin Largest organ and

The Integumentary System AKA: Skin Largest organ and system of body Varies in thickness: eyelids ( 1/50 in) to soles (1/4 in) Changes in the skin often indicate other body disorders: anemia, shock, liver and respiratory disorders

6 Main Functions: Protection (of underlying tissues) Excretion (water, salts, organic compounds) Maintenance of Body Temperature (perspiration) Perception of Stimuli (sensitivity: temperature, touch, pressure, pain) Immunity Synthesis of Vitamin D

6 Main Functions: Protection (of underlying tissues) Excretion (water, salts, organic compounds) Maintenance of Body Temperature (perspiration) Perception of Stimuli (sensitivity: temperature, touch, pressure, pain) Immunity Synthesis of Vitamin D

Layers of the Skin

Layers of the Skin Epidermis Outermost layer Made of 5 smaller layers Contains no blood vessels Contains melanocytes Cells constantly shed and replaced

Layers of the Skin Dermis Also called corium or “true skin” Elastic framework gives skin strength Contains Blood vessels Nerves Involuntary muscle Sweat & oil glands Hair follicles

Layers of the Skin Subcutaneous tissue Innermost layer Composed of various tissues and fat cells Connects skin to underlying muscles

Glands of the Skin Sudoriferous Coiled tubes extend through dermis to open on surface of skin at a pore Produce sweat

Glands of the Skin Sebaceous Oil glands Assoc w/ hair follicle to keep hair from being dry & brittle Present on entire body except soles and palms Ceruminous Modified sweat gland in ear canal, producing wax

Accessory Parts: THE NAIL Nails Densely packed dead epithelial cells Protects ends of phalanges Nail Body: pink due to underlying capillaries and white at end Nail Root: buried under skin layers. Lanula is white due to thickened stratum basale.

Accessory parts: THE HAIR Hair Consists of : -a shaft above the surface -a root that penetrates the dermis and subcutaneous layer - The cuticle -A hair follicle *New hairs develop from the matrix in the bulb

Accessory Parts: THE HAIR Hair serves to block foreign particles from entering the body through structures such as the nose and eyes Hair acts as a sensory alert and sends messages of the surrounding environment.

Accessory Parts: The HAIR Hair Growth Occurs in a growing stage and a resting stage • Growth Stage • • Lasts for 2 -6 years Resting stage • Lasts for 3 months **Old hair falls out as growth stage starts again and is affected by hormones Hair color is due to the amount and type of melanin

Functions of Skin Absorption Beneficial substances absorbed Excretion Eliminate waste products through sweat

Functions of Skin Regulation of body temperature Dilation of blood vessels allow excess heat to escape Constriction of blood vessels helps retain heat Storage Adipose tissue for energy Some vitamins (ESPECIALLY VITAMIN D)

Functions of Skin Protection Barrier to UV rays Barrier against pathogens Holds in moisture Temperature regulations Sensory Nerves present in skin respond to pain, pressure, heat & cold

Abnormal Skin Colors Melanin Brownish-black Absorbs UV light Erythema Reddish

Abnormal Skin Colors Jaundice Yellowish Cyanosis Bluish discoloration

Skin Diseases & Disorders Athlete’s foot Contagious fungal infection transmitted by wet floors Cellulitis Bacterial infection of dermis and subcutaneous layer

Skin Diseases & Disorders Contact dermatitis Skin rash resulting from exposure to irritant Decubitis ulcer Sores over bony parts of body due to prolonged pressure

Skin Diseases & Disorders Eczema Non contagious inflammatory skin disorder caused by reaction to allergen or irritant Impetigo Acute, contagious skin disease caused by Staph and/or Strep

Skin Diseases & Disorders Malignant Melanoma Most serious form of skin cancer Caused by overexposure to sun Psoriasis Chronic skin disordertoo many epidermal cells produced

Skin Diseases & Disorders Warts Common, benign papilloma caused by a virus Extreme case of HPV (human papilloma virus)

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