Integumentary System Study Notes

Anatomical Structure of the Integumentary System

• Epidermis: The outermost layer of the skin, which includes:
  • Stratum corneum: The surface layer consisting of dead, keratinized cells.
  • Basal layer: The deepest part of the epidermis where new cells are generated and melanocytes are located.
• Dermis: The layer beneath the epidermis containing blood vessels, nerves, and glands.
• Subcutaneous tissue: Also known as the hypodermis, this layer serves several critical functions:
  • Binds the dermis to underlying structures.
  • Stores fats for energy and protection.
  • Insulates and cushions the body against impact.
  • Assists in the regulation of body temperature.

Accessory Organs of the Skin

• Sebaceous Glands: Glands that produce sebum (oil) to lubricate the skin and hair.
• Sudoriferous Glands: Sweat glands responsible for perspiration and thermoregulation.
• Hair: Thread-like structures originating in follicles within the dermis.
• Nails: Hardened plates of keratin that protect the tips of fingers and toes.

Functions of the Integumentary System

• Protection: Covers and protects the body from pathogens, ultraviolet radiation, and other harmful substances.
• Secretions: Sweat and oil glands produce secretions that maintain the skin's health and flora.
• Sensory Perception: Contains an intricate network of sensory receptors that detect external stimuli.
• Thermoregulation: Regulates body temperature through sweat production and blood flow adjustments.
• Synthesis: Facilitates the synthesis of Vitamin D when exposed to sunlight.
• Pigmentation: Melanocytes produced in the basal layer give color to the skin via melanin, protecting against sun damage.
• Sensation: Provides nerve endings to sense heat, cold, pressure, and touch.

Medical Terminology: Combining Forms

• $cutane/o$, $dermat/o$, $derm/o$: Skin
• $adip/o$, $lip/o$, $steat/o$: Fat
• $hidr/o$, $sudor/o$: Sweat
• $ichthy/o$: Dry, scaly
• $cyan/o$: Blue
• $melan/o$: Black
• $kerat/o$: Horny tissue; hard; cornea
• $myc/o$: Fungus (plural: fungi)
• $onych/o$: Nail
• $pil/o$, $trich/o$: Hair
• $scler/o$: Hardening; sclera (white of eye)
• $seb/o$: Sebum, sebaceous
• $squam/o$: Scale
• $leuk/o$: White
• $erythr/o$: Red

Medical Terminology: Suffixes

• $-derma$: Skin
• $-oid$: Resembling
• $-phoresis$: Carrying; transmission
• $-plasty$: Surgical repair

Build Medical Words Exercise

• Softening of the nail(s): $onych/o/malacia$
• Treatment with cold: $cry/o/therapy$
• Discharge or flow of sebum: $seb/o/rrhea$
• Pertaining to under the skin: $sub/cutane/ous$
• Abnormal condition of blue (skin): $cyan/osis$
• Condition of sweat: $sudor/esis$
• Tumor of the nail or nail bed: $onych/oma$
• White cell: $leuk/o/cyte$
• Black cell: $melan/o/cyte$
• Skin that is dry: $xer/o/derma$
• Transplantation of same (species): $homo/graft$ or $allo/graft$
• Tumor (composed of) cancer: $carcin/oma$
• Skin (condition associated) with pus: $py/o/derma$
• Instrument to cut skin: $dermatome$ or $dermatotome$
• Tumor (consisting) of fat: $adipoma$, $lipoma$, or $steatoma$
• Excision or removal of a nail: $onychectomy$
• Skin that is blue (in color): $cyanoderma$
• Surgical repair of the skin: $dermatoplasty$

Basal Cell Carcinoma (BCC)

• Signs and Symptoms:
  • A malignancy of the basal layer of the skin.
  • Commonly caused by repeated overexposure to the sun.
  • A locally invasive tumor that rarely metastasizes (spreads to other sites).
  • Tumors grow slowly but commonly ulcerate.
• Demographics: Predominant in fair-skinned men older than $60$ years.
• Treatment:
  • Determined by size, shape, location, and invasiveness.
  • Curettage and electrodessication.
  • Cryotherapy and laser therapy.
  • Chemotherapeutic drugs.
  • Surgical excision (the primary choice in $90\%$ of cases).
  • Irradiation or chemosurgery.

Abscess, Furuncles, and Carbuncles

• Signs and Symptoms:
  • An abscess is a localized collection of pus at the infection site, characteristically a staphylococcal infection.
  • A furuncle (boil) is an abscess in a hair follicle and adjacent subcutaneous tissue.
  • A carbuncle is a cluster of furuncles in the subcutaneous tissue.
  • Affected skin is often tender, painful, swollen, and exhibits erythema (redness) and edema (swelling).
  • Lesions may enlarge, soften, open, and discharge pus and necrotic material.
  • Mild fever may occur.
• Treatment:
  • Thorough cleansing with soap and water.
  • Hot, wet compresses to promote vasodilation and drainage.
  • Topical antibiotics.
  • Incision and drainage ($I\&D$) after the lesion has matured.

Psoriasis

• Signs and Symptoms:
  • An inflammatory chronic condition with thick, flaky, red patches covered by silvery scales.
  • Commonly involves pruritus (itching).
  • Affected areas appear dry, cracked, and encrusted.
  • Common sites: Scalp, outer sides of arms and legs (especially elbows and knees), umbilicus, and genitalia.
  • Caused by excessive development of the basal layer, leading to hyperkeratosis (overgrowth of the horny layer).
• Treatment:
  • Goal: Reduce inflammation and slow rapid cell growth.
  • Keep skin moist and lubricated with coal tar, Vitamin D, or corticosteroid drugs.
  • Photochemotherapy ($PUVA$): Exposure to ultraviolet-A ($UVA$) light to slow hyperkeratosis.
  • Ultraviolet-B ($UVB$): Light therapy or natural sunlight to retard cell production.
  • Excimer laser: A powerful form of $UVB$ light targeted at plaques to control scaling.

Acne Vulgaris

• Signs and Symptoms:
  • Inflammatory disease of sebaceous glands and hair follicles.
  • Characterized by papules, pustules, and comedones (blackheads/whiteheads).
  • Most common in ages $12$ to $35$ years.
  • Located on face, neck, shoulders, chest, and back.
  • Causes: Hormone changes during puberty, genetic predisposition, stress, and external irritants (soaps/cosmetics).
• Treatment:
  • Reducing bacterial count and sebaceous gland activity.
  • Preventing follicle inflammation.
  • Topical antibacterial solutions or oral antibiotics.
  • Retin-A ($Vitamin A$ derivatives) to reduce oil and promote drying/peeling.

Scabies and Impetigo

• Scabies:
  • Contagious parasitic infection caused by the itch mite.
  • Symptoms: Intense pruritus, sensation of crawling, and a rash.
  • Lesions: Excoriated and threadlike, appearing between fingers, wrists, elbows, axilla, waist, nipples, buttocks, and genitalia.
  • Treatment: Topical scabicides (creams/lotions applied neck-to-feet overnight), antipruritics, and oral antihistamines.
• Impetigo:
  • Contagious, superficial skin infection.
  • Manifests as vesicles or pustules that rupture to form thick yellow crusts.
  • Commonly found on legs, and less often on face, trunk, and arms.
  • Causes pruritus and may lead to ulcerations and scarring.
  • Treatment: Systemic antibiotics, cleansing lesions $2$ to $3$ times daily, and strict hygiene.

Additional Medical Vocabulary

• Alopecia: Absence or loss of hair, specifically on the head; baldness.
• Débridement: The removal of necrotic (dead) or foreign tissue from a traumatic or infected area (via surgery, enzymes, or chemicals) to promote healing.
• Ecchymosis: Skin discoloration appearing as a large, irregular hemorrhagic area (blue-black to yellow); known as a bruise.
• Hematoma: An elevated, localized collection of blood trapped under the skin resulting from trauma.
• Urticaria: Allergic reaction with pale, red, elevated itchy patches; also known as wheals or hives.
• Vitiligo: Localized loss of skin pigmentation resulting in milk-white patches; also called leukoderma.

Diagnostic and Surgical Procedures

• Allergy Skin Tests:
  • Intradermal Test: Subcutaneous injection of small amounts of extracts to observe for reactions.
  • Scratch (Prick) Test: Placement of allergens on a lightly scratched skin area.
• Biopsy: Excision of tissue for microscopic evaluation to confirm diagnosis, estimate prognosis, or track disease.
• Mohs Surgery: Progressive excision and examination of layers of cancer-containing skin until only cancer-free tissue remains.
• Skin Grafting:
  • Allograft (Homograft): Healthy tissue from one person to another.
  • Autograft: Healthy tissue transferred from one site to another on the same individual.
  • Synthetic: Artificial skin produced from collagen fibers; healing skin grows into the graft as it disintegrates without rejection.
  • Xenograft (Heterograft): Dermis only, transplanted from a foreign donor (typically a pig) to a human.

Pharmacology

• Antibiotics: Used to destroy bacteria causing skin infections.
• Antifungals: Used to destroy fungi infecting the skin (e.g., ringworm, athlete's foot).
• Antipruritics: Used to reduce severe itching.
• Corticosteroids: Anti-inflammatory drugs used to treat skin inflammation (e.g., poison ivy rashes).

Questions & Discussion

• Q: What does the term integument mean?
  • A: It refers to the skin.
• Q: What are the accessory structures of the skin?
  • A: Hair, nails, and glands (sweat and oil).
• Q: What happens when Mr. T is told his basal cell carcinoma will not spread but is localized?
  • A: This means it will not undergo metastasis, but it may still destroy adjacent tissue.
• Q: A $70$-year-old man has skin cancer from sun overexposure; where is the most common site?
  • A: The face.
• Q: If a growth is noncancerous, how is it charted?
  • A: It is charted as benign.
• Q: How should a nurse explain an abscess to Sue?
  • A: It is a localized collection of pus at an infection site, usually caused by the bacterium Staphylococcus.
• Q: What is the overgrowth of the horny layer in psoriasis called?
  • A: Hyperkeratosis.
• Q: What drug treats Mr. R's athlete's foot or Mrs. K's ringworm?
  • A: An antifungal drug.
• Q: What transplant was used for Mr. G, the fireman, using pig tissue?
  • A: A xenograft.