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The Integumentary System. The skin is considered to be: A membrane because it covers the body An organ because it contains several kinds of tissues A system because it has organs and other parts that work together for a specific function.
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The skin is considered to be: • A membrane because it covers the body • An organ because it contains several kinds of tissues • A system because it has organs and other parts that work together for a specific function
On an average adult, the skin covers over 3,000 square inches of surface area and accounts for about 15% of total body weight.
Functions • Protection • Sensory perception • Regulation of body temperature • Storage • Absorption • Excretion • Production
3 layers to skin: • Epidermis • Dermis • Subcutaneous
Epidermis • Outermost layer of skin • Made of five to six smaller layers • Contains no blood vessels or nerve cells • Complete regeneration every 35-45 days
Dermis • Called the “true skin” • Contains blood vessels, lymph vessels, nerves, involuntary muscles, sweat and oil glands and hair follicles • Ridges in the dermis forms unique patterns for each individual (papillae) • Patterns are used for identification purposes (fingerprints)
Subcutaneous (hypodermis) • Innermost layer of skin • Made of elastic and fibrous connective tissue and adipose (fatty) tissue • Connects skin to underlying muscles
Glands of the skin: • Sudoriferous glands • Sebaceous glands
Sudoriferous glands • “Sweat glands” • Coiled tubes that extend through dermis • Open on surface of skin at an opening called a pore • Eliminate sweat or perspiration that contains water, salts, and some body wastes • Sweat contains body wastes • Basically odorless • When sweat interacts with bacteria on skin, body odor occurs
Sebaceous glands • Oil glands • Usually open onto a hair follicle • Produce oil called sebum • Keeps hair from becoming dry and brittle • Slightly acidic, so it acts as an antibacterial and antifungal secretion to help prevent infections • Blackheads or pimples occur when oil glands becomes plugged with dirt and oil
Sebaceous Glands • Glands are located all over the body except for soles of feet and palms • Sebaceous glands help slow water loss during dry weather
Skin Color—Albino • Absence of skin pigments • Skin has pinkish tint • Hair is pale yellow or white • Eyes are red in color and sensitive to light
Skin Eruptions • Macules- flat, (ex. Freckles) • Papules- firm, raised areas (ex. Pimples) • Vesicles-blisters (ex. chickenpox) • Pustules-pus filled sacs (ex.acne) • Crusts- dried pus & blood (ex. scabs) • Wheals- itchy elevated areas (ex. Bites) • Ulcer-deep loss of skin surface
Sunburn • Inflammation of the skin that results to overexposure of UV radiation
Skin Cancer • Cancer of the skin. The most common type of cancer. • Three types: • Basal cell carcinoma • Squamous cell carcinoma • Melanoma
Squamous Cell is more common among fair skinned people and people >50yo Melanoma (change in color and irregular border Basal Cell-appears at areas with increased sun exposure
Causes: Over exposure to the sun, prolonged use of tanning beds, irritating chemicals, or radiation
Varicella (chicken pox) • Highly contagious illness caused by a virus. Starts with vesicles and spreads quickly throughout body. Fever accompanies it.
Psoriasis • Chronic, non-contagious skin disease with periods of exacerbations and remission. • Symptoms: Thick, red areas covered with white or silver scales.
Cause: Unknown(stress, cold weather, pregnancy, sunlight exacerbate the disease)
MolluscumContagiosum • Contagious viral infection of the skin
Impetigo • Highly contagious skin infection usually caused by streptococci or staphylococci organisms.
Furuncle (Boil) • A painful sore with a hard core filled with pus
Cellulitis • Inflammation of body tissue characterized by swelling, redness, and pain.
Acne Vulgaris • Inflammation of the sebaceous glands.
Cause: Unknown(possible hormone related or increased secretion of sebum)
Shingles (Herpes Zoster) • Acute inflammation of nerve cells and is caused by the herpes virus.