Chapter 3: Dermatology Integumentary System

Dermatology

studies the anatomy and physiology of the integumentary system

How do dermatologists treat integumentary diseases?

by using lab and diagnostic tests, medical and surgical procedures, and drugs

Integument/o

skin

-ary

pertaining to

cutane/o

skin

-ous

pertaining to

What are the 2 layers of the skin?

epidermis and dermis

Epidermis

• squamous layer

• made of living and dead cells (surface cells are dead and filled with the fibrous protein keratin)

• form protective layer but are always undergoing exfoliation

• dead cells slightly acidic and discourage microorganism growth

• deep part of epidermis is basal layer

• no blood vessels

• contains melanocytes

Basal layer

made of living cells that are constantly dividing and being forced upward

Melanocytes

produce the pigment melanin that absorbs the suns UV light

Melan/o

black

-cyte

cell

Dermis

• below epidermis

• made of connective tissue

• contains collagen and elastin

• contains arteries, veins, and nerves

• houses hair follicles, sebaceous glands, and sweat glands

• has dermatomes

Dermatome

area of skin that sends sensory information to spinal cord (also used to refer to a medical instrument)

Sebaceous glands

• exocrine glands

• produce sebum that travels through a duct to a hair follicle

• sebum coats the hair shaft and moisturizes the skins surface

Sudoriferous glands

• sweat glands

• exocrine glands

• secrete sweat through duct that opens into a pore in the skin

• sweat: water, sodium, small amounts of body waste

• sweat is odorless but takes on oder when contacts bacteria on skins surface

Hair

• covers most of body

• consistency and color vary from one part of the body to another

• melanocytes gice color to hair

• each hair forms in a hair follicle in the dermis

• cells filled with keratin (makes the hair shaft strong)

Piloerection (errector pili muscle)

• occurs when skin is cold

• errector pili muscle at the base of the hair follicle contracts

• hair stands up and causes a “goosebump”

pil/o

hair

erect/o

stand up

-ion

action ot condition

Nails

• nail plate

• nail root (under skin on upper surface of finger)

• lunula (white half moon at base of fingernail)

• cuticle (edge around base of nail)

• nail bed (pink part that lies under nail plate)

Subcutaneous tissue (sub Q or subcu)

• loose connective tissue beneath the dermis

• composed of adipose tissue (contains lipocytes)

• cushions and insulates the body and protects internal organs

• thickness varies with amount of fat stored

Skin functions: protection

• skins first line of defense

• acidic epidermis discourages microorganism growth

• keratin in epidermal cells makes skin waterproof

• sweat and sebum contain antibodies and enzymes that kill bacteria

What does the epidermis do in terms of protection?

discorages microorganism growth

What does keratin in epidermal cells do in terms or protection?

make the skin waterproof

What does sweat and sebum contain and do in terms of protection?

contain antibodies and enzymes and kill bacteria

Skin functions: repair

• cells in basal epidermis move to the surface and cover the wound

• when a wound is deep, a blood clot and scab form

• new cells from the dermis and basal epidermis fill in the wound

Skin functions: sensation

• sensory receptors in dermis respond to touch, pressure, vibration, pain and temperature

• nervous system skin sensations through the nerves to the spinal cord and then interprets them to the brain

Skin functions: vitamin D synthesis

• UV rays from the sum convert epidermal cholesterol into vitamin D

• helps the body absorb calcium from foods

• dark-skinned people may need a longer exposure to sunlight to meet needs

Thermoregulation

process of controlling and adjusting body temperature

Sub Q tissue

stores fat and conserves body heat

Piloerector muscles

contract to create heat at the skins surface

Sudoriferous glands

produce sweat that cools the skin

Dermal blood vessels

dilate to release heat from the skin

Subcutaneous tissue

stored layer of fat that conserves internal body heat

Homeostasis

process of maintaining balance and stability of body systems

Dermatitis

any infection of inflammation of the skin

dermat/o

skin

-itis

infection of, inflammation of

Edema

excessive amounts of fluid move from the blood into the dermis or subQ tissue and cause swelling

Hemorrhage

injury to the blood vessels that releases blood into the skin

hem/o

blood

-rrhage

excessive discharge; excessive flow

Lesion

any observable damage or variation from normal skin, whether from disease or injury

Neoplasm

new growth on the skin, benign or malignant

neo-

new

-plasm

growth

Pruritus

caused by the release of histamine during an allergic reaction of the skin (itching)

Rash

any type of skin lesion that is pink to red (on light-colored skin or purplish or darkened i=on dark-colored skin), flat or raised, itchy or not itchy

Xeroderma

excessively dryness of the skin

xer/o

dry

-derma

skin

Albinism

genetic mutation that causes a lack of pigment in the skin, hair, and iris of eye

Cyanosis

bluish-purple discoloration of the skin and nails

cyan/o

blue

-osis

condition, process

Erythema

red discoloration of the skin; may be local or over large areas of skin

Jaundice

yellowish discoloration of the skin in light-skinned persons and of the palms and soles in dark-skinned persons; yellowish discoloration of whites of the eyes in both

Necrosis

gray-to-black discoloration of the skin in areas where the tissue has died

nerc/o

dead tissue

-osis

condition, process

Vitiligo

autoimmune disorder in which melanocytes are slowly destroyed

Abrasion

sliding or scraping injury that mechanically removes the epidermis

Blister

• fluid-filled sac with a thin, transparent covering of epidermal cells

  • occurs when a repetative rubbing injury separates the epidermis from dermis, creating a fluid-filled sac

Burns

heat, electrical current, chemicals, and radiation or x-rays can create a burn of the epidermis or dermis

Superficial burn (first-degree burn)

• involves only the epidermis

• there is erythema, pain, and swelling but no blisters

Full-thickness burn (third-degree burn)

• involves epidermis, dermis, and sometimes subcutaneous tissue and muscle layer beneath

• if burn destroys nerves in dermis, theres a local anesthesia with loss of sensation of pain

Callus

repetitive rubbing injury the causes the epidermis to gradually thicken into a wide, elevated pad

Cicatrix (scar)

fibrous tissue composed of collagen; forms as an injury heals

Excoriation

superficial injury with a sharp object that creates a linear scratch on the skin

Keloid

• a very firm, abnormally large scar

• grows larger than the original injury bc of overproduction of collagen as injury heals

Laceration

• linear penetration wound

• clean cut or torn, ragged skin edges

Pressure injury

epidermis and dermis break down, resulting in a shallow or deep ulcer

Abcess

localized pus-containing pocket under the skin caused by a bacterial infection

Furuncle

abscess around a hair follicle

Carbuncle

several furuncles

Cellulitis

infection and inflammation that spreads through the skin, subcutaneous tissue, and muscle

cellul/o

cell

-itis

infection of, inflammation of

Herpes

• infection caused by the herpes virus

• clusters of vesicles, erythema, edema, and pain

• vesicles rupture, releasing clear fluid that forms crusts

  • type 1 and 2

  • herpes whitlow

  • varicella-zoster

Tinea

• Skin infection cause by a fungus that feeds on epidermal cells

• severe itching and burning with scaly lesions that may appear red or another color depending on persons skin color

  • Tinea capitis

  • Tinea corporis

  • Tinea cruris

  • Tinea pedis

Verruca (wart)

• irregular, rough skin lesion caused by the human papillomavirus

• usually occurs on hands, fingers, soles of feet (plantar wart)

Pediculosis

infestation of parasitic lice on their eggs (nits) in the scalp, hair, eyelashes, or genital hair

pedicul/o

lice

-osis

abnormal condition; process

Scabies

infestation of parasitic mites that tunnel under the skin and produce vesicles that are itchy

Contact dermatits

local reaction from contact with a substance that is an allergen or irritant

Urticaria

• local allergic reaction due to foods, plants, animals, insect bites, or drugs

• raised areas of redness and edema that appear suddenly

• itching causes areas to enlarge

  • hives

  • wheals

  • welts

Actinic keratosis

raised, irregular, rough area of skin is dry and feels like sandpaper; develops in middle-aged persons in areas exposed to the sun; area can become cancerous

actin/o

rays of sun

-ic

pertaining to

Hemangioma

benign mass of superifcial, dilated blood vessels that is present at birth

hem/o

blood

angi/o

blood vessel; lymphatic vessel

-oma

mass; tumor

Nevus

benign skin lesion that is present at birth and has a variety. of colors and shapes

Papilloma

soft, flesh-colored growth the protrudes from the skin; grows as a flap or polyp on a stalk

papill/o

elevated structure

-oma

mass; tumor