Jesus Carranza Per. 2 Integumentary System

Functions of the Skin

Layers of the Skin

Accessory organs

Skin Cancer and ABCD rule

Burns and rule of 9

Dermis (middle)

Hypodermis (bottom)

Epidermis (top)

Stratum corneum (superficial layer) (horny layer)

Stratum lucidum (only thick skin) (clear layer)

Stratum granulosum (granular layer)

Stratum spinosum (prickly layer)

Stratum basale (basal layer)

Reticular dermis (bottom)

Papillary dermis (top)

Adipose Tissue

Protection

Body temperature regulation

Cutaneous sensations

Metabolic functions

Blood reservoir

Excretion

Chemical barrier

Physical barrier

Biological barrier

Cutaneous sensory receptors

Squamous cell carcinoma (Second most common)

Melanoma (most dangerous)

Basal cell carcinoma (most common)

ABCD

B: border irregularity

C: color

A: asymmetry

D: diameter

Rules of 9

Degrees

2nd: Epidermal and upper dermal damage, Partial thickness

3rd: Entire thickness , Nerve endings destroyed

1st: Epidermal damage only

11 sections = 9% of body surface
genitals = 1%

Used to estimate volume of fluid loss

Cancer of melanocytes

keratinocytes of stratum spinosum

Can metastasize

Least malignant

Stratum basale cells proliferate, invade dermis/hypodermis

Secrete limited amounts of nitrogenous wastes

hold up to 5% of the body’s total blood volume

Skin vessels can constricted to shunt blood

Synthesize vitamin D

Chemicals from keratinocytes can disarm some carcinogens

Keratinocytes can activate some hormones

Makes collagenase

Exteroreceptors respond to stimuli outside body

Free nerve endings sense painful stimuli

Skin secretes many chemicals

Acid mantle: low pH of skin retards bacterial multiplication

Melanin provides a chemical barrier against UV radiation damage

Chemicals have limited penetration of skin

Flat, dead, keratinized cells of stratum corneum, surrounded by glycolipids

Blocks most water and water-soluble substances

Epidermis contains phagocytic cells

Dermis contains macrophages

DNA can absorb harmful UV radiation, converting it to harmless heat

Hair

Nails

Glands

Oil (sebaceous): lubricate skin/hair, help prevent water loss, antibacterial properties, secrete sebum, everywhere except palms and soles

Sweat (sudoriferous)

Apocrine: Sexual scent, axillary and anogenital areas, ducts emptying into hair follicles

Eccrine (merocrine): Temperature control, antibacterial properties, on palms, soles, and forehead, empty from skin

Ceruminous: lining of external ear canal; secrete cerumen (earwax)

Mammary: secrete milk

Nail root: contains nerves and blood vessels so that cell reproduction can occur

Eponychium (cuticle): nail fold that projects onto surface of nail body

Lunule (lunula): thickened nail matrix, appears white

Nail plate: visible part that lays on nail bed, made by Keratinisation

Free edge: end of the nail plate

Nail folds: skin folds that overlap border of nail

Nail matrix: thickened portion of bed responsible for nail growth

Nail bed: epidermis underneath keratinized nail plate

Regions

Follicle

Cool External Environment: dermal bloods constrict and skin temp drops to slow passive heat loss

Cool body down: dilation of dermal vessels can increase sweat gland activity

Normal Body Temp: Sweats glands produce unnoticeable sweat

Medulla: central core of large cells and air spaces

Cortex: several layers of flattened cells surrounding medulla

Cuticle: outer layer consisting of overlapping layers of single cells

Hair bulb: expanded area at deep end of follicle

Hair follicle receptor (or root hair plexus): sensory nerve endings that wrap around bulb

Epithelial root sheath: Derived from epidermis

Hair matrix: actively dividing area of bulb that produces hair cells

Arrector pili: small band of smooth muscle attached to follicle

• Hair papilla: Dermal tissue containing a knot of capillaries that supplies nutrients to growing hair

Functions: Warn of insects on skin, Hair on head guards against physical trauma, Protect from heat loss, Shield skin from sunlight