S KIN AND BODY MEMBRANES

D ERMIS Two layers Papillary layer (upper dermal region) Reticular layer (deepest skin layer)

D ERMIS Papillary layer (upper dermal region) Projections called dermal papillae Capillary loops Pain receptors and touch receptors

D ERMIS Reticular layer (deepest skin layer) Blood vessels Sweat and oil glands Deep pressure receptors

D ERMIS O VERVIEW Collagen fibers give skin its toughness Elastic fibers give skin elasticity Blood vessels play a role in body temperature regulation

S KIN A PPENDAGES Glands Hair Hair follicles Nails

S EBACEOUS GLANDS Produce oil Keep skin lubricated Kills bacteria Glands are activated at puberty

S EBACEOUS GLANDS

S WEAT GLANDS Produce sweat Widely distributed in skin Two types Eccrine Open via duct to pore on skin surface Apocrine Ducts empty into hair follicles

S WEAT GLANDS

H AIR Produced by hair follicle Consists of hard keratinized epithelial cells Melanocytes provide pigment for hair color

H AIR Hair follicle- shaft, follicle (root) medulla (inner), cortex (outer), cuticle (cover) Growth- 4 in./year or 2 mm/week

H AIR Associated hair structures Hair follicle Arrector pili muscle Sebaceous gland Sweat gland

N AILS Scale-like modifications of the epidermis Heavily keratinized (very hard)

N AILS Consists of: free edge Body Root Cuticle Lunula Growth- 0.5 mm/week

N AILS

Did you know that your fingernails grow much faster than your toe nails? 3-4 times faster!

N AILS Related to length of outermost finger bone Blood flow Use-stimulates growth

S KIN I NFECTIONS AND A LLERGIES Contact dermatitis Exposures cause allergic reaction Cold sores Caused by virus Impetigo Caused by bacterial infection Psoriasis Cause is unknown Triggered by trauma, infection, stress

S KIN I NFECTIONS AND A LLERGIES

B URNS Burns Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals

B URNS Associated dangers Dehydration Electrolyte imbalance Circulatory shock

R ULE OF N INES Way to determine the extent of burns Body is divided into 11 areas for quick estimation Each area represents about 9% of total body surface area

R ULE OF N INES

S EVERITY OF B URNS 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

S EVERITY OF B URNS

C RITICAL B URNS Burns are considered critical if Over 25% of body has second-degree burns Over 10% of the body has third-degree burns There are third-degree burns of the face, hands, or feet