Download Skin: Integumentary System

Chapter 12
Skin:
Integumentary
System
Related Combining Forms
Structure
Related Combining Forms
Skin
cutane/o, dermat/o, derm/o
Sebaceous glands
seb/o
Sweat glands
hidr/o
Hair
pil/i, pil/o
Nails
onych/o, ungu/o
Integumentary System
• Consists of skin and its related structures
(sebaceous glands, sweat glands, hair, and
nails)
• Average adult has two square yards of skin,
making it the largest body organ
Functions of Skin
• Keeps the body waterproof, hence preventing
fluid loss
• When intact, skin blocks the entrance of
pathogens
• Contains receptors for the sense of touch
• Synthesizes vitamin D from the sun
Functions of Related Structures
• Sebaceous glands
– Secrete sebum that lubricates skin and
discourages growth of bacteria on skin
• Sweat glands
– Assist with body water content and
temperature regulation
– Excretion of small amounts of metabolic
wastes
Functions of Related Structures
• Hair
– Helps control the loss of body heat
• Nails
– Protect dorsal surface of last bone of each toe
and finger
Structures of Skin and Its Related Structures
• Skin
– Specialized tissues
– Three layers
• Epidermis
• Dermis
• Subcutaneous
– (cutane: skin; -ous: pertaining to)
Structures of Skin and Its Related Structures
Epidermis
– (epi-: above or upon; derm: skin; -is: noun
ending)
• Outermost layer of skin
• Made of specialized epithelial tissues
• Contains no blood vessels or connective
tissue
• Depends on the lower layers for nourishment
Epidermis
• Epithelial tissues
– Form protective covering for internal and
external surfaces of the body
• Squamous epithelial tissue
– Forms upper layer of epidermis
– Flat, scaly cells continuously shed
Epidermis
• Basal layer
– Lowest layer of epidermis
– Site of new cell production
– When cells reach surface, they die and
become filled with keratin
• Keratin
– Fibrous, water-repellent protein
• Soft keratin: component of epidermis
• Hard keratin: found in hair and nails
Epidermis
• Melanocytes
– Special cells in basal cell layer
– Produce and contain dark brown to black
pigment known as melanin
• Melanin
– Pigment that determines color of skin,
produces freckles and age spots
– Protects skin from some of the harmful UV
rays
Dermis
• Directly below epidermis
• Contains connective tissue, blood and lymph
vessels, nerve fibers, hair follicles,
sebaceous glands, and sweat glands
• Sensory nerve endings
– Sensory receptors for touch, temperature,
pain, and pressure
Tissues Within Dermis
• Collagen
– Tough flexible fibrous protein found in skin,
bones, cartilage, tendons, and ligaments
• Mast cells
– Found in connective tissue of dermis
– Respond to injury, infection, or allergy by
producing and releasing heparin
(anticoagulant) and histamine (causes allergic
response)
Subcutaneous Layer
• Located below the layers of skin
• Connects skin to the surface muscles
• Made of loose connective tissue and adipose
tissue
• Lipocytes manufacture and store large
quantities of fat
– (lip/o: fat; -cytes: cells)
Sebaceous Glands
• Located in dermis
• Closely associated with hair follicles
• Sebum
– Oily substance released through ducts
opening into hair follicles
– Lubricates skin
– Acidic, thus discourages growth of bacteria on
skin
Sebaceous Glands
• Mammary glands
– Produce milk
– Also part of the reproductive system
Sweat Glands
• Sudoriferous glands
• Located on almost all body surfaces
• Two types
– Apocrine
• Found at hair follicles
– Eccrine
• Open onto skin
• Most numerous in palms, soles, and forehead
Sweat Glands
• Pores
– Opening on the surface of skin
– Act as ducts of the sweat glands
• Perspiration
– Secreted by sweat glands
– 99% water plus salt and metabolic waste
– Evaporation of sweat cools the body
Sweat Glands
• Hidrosis
– Production and excretion of perspiration
Hair
• Composed of dead protein cells filled with
hard keratin
• Color of hair determined by melanin
• Hair follicles
– Sacs holding the root of hair fibers
• Arrector pili
– Muscle fibers attached to hair follicles that
cause hair to stand erect, reducing heat loss
Nails
• Unguis (fingernail or toenail)
• Keratin plate protecting dorsal surface of the
last bone of each finger and toe
• Nail body
– Translucent
– Molded to surface of underlying tissues
– Make of hard, keratinized plates of epidermal
cells
Nails
Nails
• Nail bed
– Joins nail body to underlying connective
tissue
– Nourishes the nail
– Blood vessels provide pink color
• Free edge
– Portion of nail not attached to the nail bed
– Extends beyond tip of the finger or toe
Nails
• Lunula
– Half-moon-shaped region at nail root
– Site of new keratin cell formation
• (lun: moon; -ula: little)
• Cuticle
– Epidermis attached to the surface of nail
• Nail root
– Fastens nail to finger/toe
Medical Specialties Related to Integumentary System
• Dermatologist
– Specializes in diagnosing/treating disorders of
the skin
• (dermat: skin; -ologist: specialist)
• Plastic surgeon
– Specializes in surgical restoration or
reconstruction of body structures
• (-plasty: surgical repair)
Medical Specialties Related to Integumentary System
• Cosmetic surgeon
– Plastic surgeon who performs operations for
aesthetic rather than medical reasons
Pathology of Integumentary System
• Sebaceous Glands
– Acne vulgaris
• Chronic inflammatory disease caused by the
overproduction of sebum around the hair shaft
– Comedo
• Noninfected lesion composed of sebum and
keratin in hair follicle
• Closed comedo: whitehead
• Open comedo: blackhead
Sebaceous Glands
– Epidermoid cyst
• Closed sac just under the skin
• Contains fatty material
– Seborrhea
• Overproduction of sebum
• (seb/o: sebum; -rrhea: flow or discharge)
Sebaceous Glands
– Seborrheic dermatitis
• Inflammation causing scaling/itching of upper
layers of skin/scalp
– Seborrheic keratosis
• Benign skin growth having a waxy appearance
• Varied colors
• Common in elderly
Sweat Glands
– Anhidrosis
• Condition of lacking sweat in response to heat
– (an-: without; hidr: sweat; -osis: abnormal condition)
– Diaphoresis
• Profuse sweating
– (dia-: through or complete; phor: movement; -esis:
abnormal condition)
– Heat rash
• Itchy rash related to the blockage of sweat glands
by bacteria and dead cells
Sweat Glands
– Hyperhidrosis
• Excessive sweating in one area or over the whole
body
– (hyper-: excessive; hidr: sweat; -osis: abnormal
condition)
– Sleep hyperhidrosis
• Hyperhidrosis during sleep
Hair
– Folliculitis
• Inflammation of hair follicles
– (follicul: hair follicle; -itis: inflammation)
– Trichomycosis axillaris
• Superficial bacterial infection of hair shafts in areas
with extensive sweat glands, such as armpits
– (trich/o: hair; myc: fungus; -osis: abnormal condition;
axill: armpit; -ary: pertaining to)
Excessive Hairiness
– Hirsutism
• Excessive body and facial hair in women, usually
occurring in a male pattern
– (hirsut: hairy; -ism: condition)
Abnormal Hair Loss
– Alopecia
• Partial or complete loss of hair
– (alopec: baldness; -ia: condition)
– Alopecia areata
• Autoimmune disorder attacking hair follicles
• Occurs in patches on scalp or elsewhere on body
Abnormal Hair Loss
– Alopecia totalis
• Loss of all hair on the scalp
– Alopecia universalis
• Total loss of hair on all parts of the body
– Androgenic alopecia
• Hair loss due to hormonal changes
• Occurs in males and females
Nails
– Clubbing
•
•
•
•
Abnormal curving of nails
Often accompanied by enlargement of fingertips
May be hereditary
May be due to changes associated with oxygen
deficiencies related to coronary or pulmonary
disease
Nails
– Koilonychia
• Outer surface of nail is concave
• Often indicates iron-deficiency anemia
– (koil: hollow or concave; onych: fingernail or toenail; -ia:
condition)
– Onychia
• Inflammation of matrix of nail
• May result in the loss of nail
Nails
– Onychocryptosis
• Edges of toenail curve inward and cut into the skin
– (onych/o: fingernail or toenail; crypt: hidden; -osis:
abnormal condition)
– Onychomycosis
• Fungal infection of nail
– (myc: fungus)
– Paronychia
• Infection of skin fold around a nail
– (par-: near)
Skin Pigmentation
• Acanthosis nigricans
– Development of dark wart-like patches on one
or more areas of skin
• Age spots
– Discoloration caused by sun exposure
• Albinism
– Genetic condition characterized by lack of
pigment in skin, hair, and irises of eyes
• (albin: white)
Skin Pigmentation
• Chloasma
– Brownish spots on face
– May occur during pregnancy, and disappear
after delivery of infant
• Vitiligo
– Irregular patches of white skin related to
destruction of melanocytes
Bleeding into Skin
• Contusion
– Injury to underlying tissues without breaking
the skin
– Discoloration caused by accumulation of
blood within the skin
• (contus: bruise; -ion: condition)
Bleeding into Skin
• Ecchymosis
– Large, irregular purplish discoloration due to
bleeding under the skin
• (ecchym: pouring out of juice; -osis: abnormal
condition)
• Purpura
– Multiple purple discoloration on skin due to
bleeding underneath the skin
• (purpur: purple; -a: noun ending)
Bleeding into Skin
Bleeding into Skin
• Petechiae
– Small, pinpoint hemorrhages less than 2 mm
in diameter
• Hematoma
– Usually due to injury
– Swelling of clotted blood trapped in tissues
– Blood is reabsorbed
• (hemat: blood; -oma: tumor)
Surface Lesions
• Crust
– Collection of dried serum and cellular debris
• Erosion
– Wearing away of a surface
• Macule
– Flat, discolored spot less than 1 cm in
diameter
Surface Lesions
Surface Lesions
• Nodule
– Solid, raised skin lesion larger than 0.5 cm in
diameter
• Papule
– Raised, red lesion less than 0.5 cm in
diameter
– Does not contain pus
Surface Lesions
• Plaque
– Scaly, solid raised area of closely spaced
papules
• Scales
– Flakes or dry patches of excess dead
epidermal cells
– Some shedding is normal
– Excessive shedding associated with the skin
disorders
Surface Lesions
• Verrucae
– Small, hard skin lesions caused by human
papillomavirus
– Also known as warts
• Wheal
– Small, itchy bump
– May be due to an allergic reaction
Fluid-Filled Lesions
• Abscess
– Closed pocket containing pus
– Due to bacterial infection
• Purulent
– Producing or containing pus
• Exudate
– Fluid leaking out of an infected wound
Fluid-Filled Lesions
• Cyst
– Abnormal sac containing fluid, or semisolid
material
• Pustule
– Small, circumscribed lesion containing pus
– Contained within a limited area
Fluid-Filled Lesions
Fluid-Filled Lesions
• Vesicle
– Blister, less than 0.5 cm in diameter
– Contains watery fluid
• Bulla
– Large blister more than 0.5 cm in diameter
Lesions Through Skin
• Abrasion
– Superficial layers are scraped away
• Fissure
– Crack-like break in the skin
• Laceration
– Torn or jagged wound
Lesions Through Skin
Lesions Through Skin
• Pressure sore
– Open ulcerated wound caused by the
prolonged pressure on an area of the skin
• Needlestick injury
– Accidental puncture wound caused by
hypodermic needle
• Ulcer
– Open lesion resulting in tissue loss around the
edges
Birthmarks
• Pigmented birthmarks
– Also known as moles or café-au-lait spots
• Vascular birthmarks
– Caused by blood vessels close to the skin's
surface
Birthmarks
• Capillary hemangioma
– Soft, raised, pink or red vascular birthmark
– Benign tissue mass
• (hem: blood; angi: blood or lymph vessels; -oma:
tumor)
• Port-wine stain
– Flat vascular birthmark made up of dilated
blood capillaries
– Creates reddish-purple discoloration
Dermatitis
• Inflammation of the skin
• Contact dermatitis
– Localized allergic response
• (dermat: skin; -itis: inflammation)
• Eczema
– Recurring dermatitis characterized by
redness, itching, and dryness
Dermatitis
• Exfoliative dermatitis
– Widespread scaling of the skin
• Pruritus
– Itching associated with the most forms of
dermatitis
• (prurit: itching)
Erythema
• Redness of skin due to capillary dilation
– (erythem: flushed; -a: noun ending)
• Erythema infectiosum
– Mildly contagious viral infection common in
children
– Also known as fifth disease
Erythema
• Erythema multiforme
– Generalized allergic reaction to illness,
infection, or medication
• Erythema pernio
– Purple-red inflammation occurring when small
blood vessels below the skin are damaged
Erythema
• Erythroderma
– Abnormal redness of entire skin surface
• (erythr/o: red; -derma: skin)
• Exanthem
– Widespread rash
• Hand, foot, and mouth disease
– Mild viral infection common in children under
5 years of age
– Sores in mouth/throat; rash on hands/feet
General Skin Conditions
• Dermatosis
– Denotes skin lesion or eruption of any type
not associated with inflammation
• Ichthyosis
– Hereditary disorders characterized by dry,
thickened, scaly skin
• (ichthy: dry or scaly; -osis: abnormal condition)
General Skin Conditions
• Lipedema
– Characterized by accumulation of fat and fluid
in tissues under the skin of hips and legs
• (lip: fat; -edema: swelling)
• Systemic lupus erythematosus
– Autoimmune disorder characterized by red,
scaly rash on face/upper trunk
• Psoriasis
– Occurrence of red papules with silvery scales
General Skin Conditions
• Roseacea
– Tiny red pimples and broken blood vessels
– Commonly seen in adults 30–60 years of age
• Rhinophyma
– Hyperplasia of tissues of nose
– Usually seen in older men
• (rhin/o: nose; -phyma: growth)
General Skin Conditions
• Scleroderma
– Autoimmune disorder in which connective
tissues become thickened and hardened
• (scler/o: hard; -derma: skin)
• Urticaria
– Itchy wheals due to allergic reaction
• (urtic: rash; -aria: connected with)
General Skin Conditions
• Xeroderma
– Excessively dry skin
• (xer/o: dry; -derma: skin)
Bacterial Skin Infections
• Carbuncle
– Cluster of furuncles
• Cellulitis
– Acute bacterial infection within connective
tissues
– Characterized by malaise, swelling, warmth,
and red streaks
Bacterial Skin Infections
• Furuncles
– Large, tender, swollen areas caused by
staphylococcal infection around hair follicles
or sebaceous glands
• Gangrene
– Death of tissue, followed by bacterial
invasion, which may also enter bloodstream
– Commonly due to the loss of circulation to the
affected tissues
Bacterial Skin Infections
• Impetigo
– Highly contagious bacterial skin infection
– Common in children
• Necrotizing fasciitis
– Caused by Group A strep that enters the body
through a skin wound
Bacterial Skin Infections
• Pyoderma
– Acute, pus-forming bacterial skin infection
• (py/o: pus; -derma: skin)
Fungal Skin Infections
• Mycosis
– Abnormal condition caused by fungus
• (myc: fungus; -osis: abnormal condition)
• Tinea
– Fungal infection on skin, hair, or nails
– Known as ringworm
Parasitic Skin Infestations
• Pediculosis
– Infestation with lice
• (pedicul: lice; -osis: abnormal condition)
• Scabies
– Skin infection caused by itch mites
Skin Growths
• Callus
– Thickening of the part of the skin caused by
repeated rubbing
• Cicatrix
– Normal scar
• Granulation tissue
– Forms during healing of a wound
Skin Growths
• Granuloma
– Small swelling of granulation tissue
– May result from inflammation, injury, infection
• (granul: granular; -oma: tumor)
• Keloid
– Thickened scar expanding beyond the
boundaries of original incision
• (kel: growth or tumor; -oid: resembling)
Skin Growths
• Keratosis
– Overgrowth and thickening of the skin
• (kerat: hard or horny)
• Lipoma
– Benign fatty tumor located between the skin
and muscle layer
• Nevus
– Small, dark skin growth developing from
melanocytes
Skin Growths
• Dysplastic nevi
– Atypical moles
– May develop into skin cancer
• Papilloma
– Benign wart-like growth on epithelial tissue or
elsewhere in the body
• (papill: resembling a nipple; -oma: tumor)
Skin Growths
• Polyp
– Mushroom-like growth from the surface of
mucous membrane
• Skin tags
– Flesh-colored polyps hanging from the body
by fine stalks
– Benign
– Tend to enlarge with age
Skin Cancers
• Malignant growth on skin
• Three types
– Basal cell carcinoma
– Squamous cell carcinoma
– Melanoma
Skin Cancers
• Actinic keratosis
– Precancerous skin growth occurring on sundamaged skin
– Lack of treatment may lead to cancer
• Basal cell carcinoma
– Malignant tumor of basal cell layer of
epidermis
– Rarely spreads
Skin Cancers
• Squamous cell carcinoma
– Malignant tumor of squamous cells of
epithelium
– Can spread quickly to other body systems
• Malignant melanoma
– Occurs in melanocytes
– Initial symptoms are change in the size,
shape, or color of a mole
• (melan: black; -oma: tumor)
Burns
• Injury caused by heat, flame, electricity, sun,
chemicals, or radiation
• Severity described according to the
percentage of the total body skin surface
affected or by depth or layer of skin involved
Diagnostic Procedures of Integumentary System
• Biopsy
– Removal of small piece of living tissue for
confirmation of diagnosis
• (bi: pertaining to life; -opsy: view of)
• Exfoliative cytology
– Cells are scraped from tissue for microscopic
examination
Treatment Procedures of Integumentary System
• Preventive measures
– Sunscreen
• Blocks harmful ultraviolet B (UVB) rays or
ultraviolet A (UVA) rays
• Measured in terms of strength of sun protection
factor (SPF)
Burn Treatment
– Depends on degree of burn, and percentage
of the body surface involved
– Burn centers provide pain relief, debridement,
dermoplasty, IV fluids and nutritional
supplements, antibiotics, cosmetic
reconstruction, and rehabilitation
Tissue Removal
– Cauterization
• Destruction of tissue by burning
– Chemabrasion
• Use of chemicals to remove outer layers of skin
– Cryosurgery
• Destruction or elimination of abnormal tissue cells
– (cry/o: cold; -surgery: operative procedure)
Tissue Removal
– Curettage
• Removal of surface material by scraping
– Debridement
• Removal of dirt, foreign objects, damaged tissue,
and cellular debris from a wound
• Prevention of infection and promotion of healing
– Irrigation and debridement
• Pressurized fluid to clean wound debris
Tissue Removal
– Dermabrasion
• Involves use of revolving wire brush or sandpaper
– Electrodesiccation
• Destruction of tissue by the use of electric spark
– Incision
• Use of surgical instrument to cut open a lesion
Tissue Removal
– Mohs' surgery
• Layers of cancerous tissue are removed and
examined under the microscope
• Procedure is repeated until margin that is clear of
all cancerous tissue is achieved
Laser and Light Source Treatments of Skin Conditions
• Laser (Light Amplification by Stimulated
Emission of Radiation)
– Laser tube filled with solid, liquid, or gas
substance is stimulated to emit light at a
specific wavelength
• Photosensitizing drug
– Administered topically or by injection
– After activation, drugs produce a form of
oxygen that kills nearby cells
Medications for Treatment of Skin
• Retinoids
– Derived from vitamin A and are used because
of their effect on epithelial cell growth
• Topical steroids
– Derivatives of natural corticosteroid hormones
– Treatment of various skin disorders
Cosmetic Procedures
• Blepharoplasty
– Surgical reduction of upper and lower eyelids
by removing sagging skin
• (blephar/o: eyelid; -plasty: surgical repair)
• Botox
– Used to reduce moderate-to-severe frown
lines, to treat migraines and muscle spasms
• Collagen replacement therapy
– Used for soft-tissue augmentation
Cosmetic Procedures
• Dermatoplasty
– Replacement of damaged skin of a patient
with the healthy tissue taken from a donor site
• Electrolysis
– Use of electric current to destroy hair follicles
• Lipectomy
– Surgical removal of fat from beneath the skin
to improve physical appearance
Cosmetic Procedures
• Liposuction
– Surgical removal of fat beneath the skin with
the aid of suction
• Rhytidectomy
– Surgical removal of excess skin and fat from
the face
• (rhytid: wrinkle; -ectomy: surgical removal)
Cosmetic Procedures
• Sclerotherapy
– Injection of a saline sclerosing solution for
treatment of spider veins (nonessential veins
seen through the skin)