BIOSCI030

Integumentar

y

Integumentary SystemReported by:Bermudez, Lips B.

Magtulis,

• Skin • Skin derivatives–Sweat glands–Oil glands–Hair–Nails Integument “Covering”

Our Skin serves mostly protective

functions

Skin Cutaneous

MembraneDry membraneOutermost

protective boundary

Skin Structure

Epidermis

Stratified squamous epithelium

KERATINIZEDKERATINIZED

Often keratinized (hardened by keratin)

Avascular – it has no blood supply of its own

Composed of five

layers or strata

Pigment (melanin) produced by melanocytes

Melanocytes are mostly in the stratum basale

Color is yellow to brown to black

Amount of melanin produced depends upon genetics and exposure to sunlight

Dermis

Dense connective tissue Two layers 1. Papillary layer (upper dermal region) Projections called dermal

papillae Some contain capillary loops

Other house pain receptors and touch receptors

• Reticular layer (deepest skin layer)

Blood vessels Sweat and oil glands Deep pressure receptors

• Collagen and elastic fibers located throughout the dermis

• Collagen fibers give skin its toughness• Elastic fibers give skin elasticity• Blood vessels play a role in body temperature

regulation

Normal Skin Color Determinants

Melanin

CaroteneHemoglobin

123

Melanin - Yellow, brown, or black pigments

Carotene - Orange-yellow pigment from some vegetables

Hemoglobin - Red coloring from blood cells in dermal capillariesOxygen content determines the extent of red coloring

Skin Appendages

Sebaceous glands - Produce oil

1. Eccrine - Open via duct to pore on skin surface2. Apocrine - Ducts empty into hair follicles

Hair - Produced by hair follicle Consists of hard keratinized epithelial

cellsMelanocytes provide pigment for hair color

• Nails - Scale-like modifications of the epidermis which is Heavily keratinized; Lack of pigment makes them colorless

Functions of the Skin

Mechanical Damage

• Mechanical Damage• Chemical Damage• Bacterial Damage• Ultraviolet Radiation• Thermal (heat or cold) damage• Desiccation

Skin Homeostatic Imbalances

• Infections and allergies• Psoriasis - Cause is unknown; Triggered by trauma, infection, stress

Burns• Burns - Tissue damage and cell

death caused by heat, electricity, UV radiation, or chemicals

• Associated dangers > Dehydration, Electrolyte imbalance, Circulatory shock

Severity of Burns• First-degree burns - Only epidermis is

damaged; Skin is red and swollen• Second-degree burns - Epidermis and upper

dermis are damaged; Skin is red with blisters• Third-degree burns - Destroys entire skin layer;

Burn is gray-white or black