ANATOMY UNIT 3 (SKIN)

The Integumentary System

composed of skin, sweat, oil gland, hair, nails (1.5-4.0mm thick)

Skin Functions

1) physical and chemical barrier protecting from outside

2) temperature regulation (vasodilation and vasoconstriction)

3) excretion of waste

4) synthesizes vitamin D

5) cutaneous sensation

Skin Structure (3 layers)

1) Epidermis

2) Dermis

3) Hypodermis

Epidermis

outermost layer; composed mostly of keratinized stratified squamous epithelium; contains 4 distinct cell types and 4-5 distinct layers

Distinct Layers of the Epidermis (from top to bottom)

1) stratum corneum

2) stratum lucidum

3) stratum granulosum

4) stratum spinosom

5) stratum basale

Stratum Corneum

flat, dead, full of keratin

Stratum Lucidum

only in thick skin

Stratum Granulosum

flat and dying keratinocytes

Stratum Spinosom

Several layers; lots of melanin and keratin

Stratum Basale

Active mitosis

Epidermis Cell Types

Keratinocytes and Melanocytes

Keratinocytes

produces keratin; tightly connected by desmosomes; made in the bottom layer and pushed upwards becoming more keratinized; those on surface die

Melanocytes

synthesize melanin (skin pigment); located at deepest layer; melanin is transferred to keratinocytes; protects against UV damage

Skin Pigments

melanin, carotene, hemoglobin

Melanin (color)

yellow, brown, or black (amount produced depends on sun exposure and genes)

Carotene

orange-yellow pigments in food

Hemoglobin

red pigment in blood cells

Dermis

Dense fibrous connective tissue; lots of collagen and elastin fibers; the “hide” of the human body; richly innervated and vascularized

Dermis layers (2)

Papillary layer & Reticular layer

Papillary Layer

projections called dermal papillae→epidermal ridges→fingerprints; capillary loops; pain receptors; meissner’s corpuscles

Capillary Loops

nourish the epidermis

Pain Receptors

free nerve endings

Meissner’s Corpuscles

light touch receptors

Reticular Layer

hair follicles; smooth muscle; glands; vessels; Pacinian corpuscle; sebacious gland; sweat glands

Pacinian Corpuscles

deep pressure

Sebacious Glands

produce sebum, moisturize skin, kills bacteria, ducts empty into hair follicles, activated at puberty, everywhere except palms and soles

Sweat Glands

Eccrine and Apocrine

Eccrine Sweat Glands

coil in the dermis; empty via duct to pore on skin surface (water sweat)

Apocrine Sweat Glands

axillary and anogenital areas; ducts empty into hair follicles (odorous sweat)

Hypodermis

not part of skin; anchors skin to underlying organs; mostly adipose

Hair

made of hard keratinized epithelial cells; hair color, melanocytes provide pigment; matrix is the growth zone; parts of the hair (shaft, hair follicle, hair root); arrector pili

Arrector Pili

smooth muscle that raises hair

Hair Function

protect from environment; regulating body temperature; increase sensory function

Nails

modification of the epidermis; heavily keratinized; colorless due to lack of melanin; nail matrix: growth occurs here; new cells rapidly die

Nail Function

protection from injury and infection; tactile sensation; strengthen fingertips; making it easier to perform tasks; fine motor skills; health indicator

Benign Cancer

not harmful

Malignant Cancer

deadly

Metastasizes

Spreads

Squamous Cell Carcinoma

scaley; least intruding; 2nd most common

Basal Cell Carcinoma

ulcerous; 2nd most intruding; 1st common

Melanoma

most deadly; most intruding

A: asymmetry

B: border

C: color

D: diameter

E: evolution

#1 Danger of Burns

Infection

Fungal Infection (Athlete’s Foot)

Fungal

Cause: hormonal changes; high blood sugar; diabetes

Symptoms: irritation; fatigue; discomfort; bumps; white patches

Treatments: topical creams; oral medication

Chicken Pox

Virus

Cause: varicella-zoster virus

Symptoms: small red bumps→blisters→scabs

Treatments: no cure; antihistamines

Shingles

Virus

Cause: reactivation of varicella-zoster virus

Symptoms: localized pain, burning, tingling, skin sensitivity

Treatments: prescription antiviral medication

Cold Sores

Virus

Cause: illness, Uv exposure, spread of virus

Symptoms: tingling; burning; fluid filled blisters

Treatments: antiviral medication; cold compress

Warts

Virus

Cause: infection of skin caused by HPV virus; enter through small cut

Symptoms: small grainy raised skin bump

Treatment: doctor administered freezing

Impetigo

Bacteria

Cause: irritated skin and bacteria

Symptoms: honey color crust over red sore

Treatments: antibiotics

Cellulitis

Bacteria

Cause: streptococcus bacteria entering through break in skin; diabetes; obesity

Symptoms: redness; swelling; warm and tight skin; fever

Treatments: pills; intravenous antibiotics

Dermatitis

Cause: irritants; weak skin barrier

Symptoms: itching; rashes; dryness; cracking; oozing

Treatments: moisturizing

Psoriasis

Cause: immune system problem where white blood cells (T cells) attack healthy skin

Symptoms: raised white patches of skin; covered with scales; knees and elbows

Treatments: skin creams; Uv light therapy

Acne

Bacteria

Cause: excess oil; clogged pores; bacteria buildup

Symptoms: whiteheads; blackheads; popules;postules

Treatments: benzoyl peroxide

Boil/Carbuncle

Bacteria

Cause: bacteria entering through hair follicles

Symptoms: painful red swollen bump filled with pus

Treatments: surgical incision drainage

Decubitous Ulcer

Cause: wound in skin and underlying tissue causing pressure that cuts blood flow

Symptoms: skin decoloration

Treatments: relieving pressure

1st Degere Burn

Cause: sun exposure

Symptoms: redness; pain; no blisters; affects only epidermis

Treatments: cool skin with water

2nd Degree Burn

Cause: deep tissue damage; hot objects; chemicals

Symptoms: pain; swollen skin; blisters; shiny; affects epidermis and part of dermis

Treatment: cover with non stick bandage

3rd Degree Burn

Cause: severe damage to all layers of skin

Symptoms: swelling; leathery skin

Treatments; IV