Integumentary System and Dermatology: Medical Terminology Study Guide

Dermatology and the Integumentary System

Introduction to Dermatology

Dermatology is the medical specialty focused on the anatomy, physiology, diseases, and treatments of the integumentary system, which includes the skin, nails, and subcutaneous tissue. Dermatologists utilize laboratory tests, diagnostic procedures, medical and surgical interventions, and pharmacological therapies to manage integumentary disorders.

Components of the Integumentary System

The integumentary system covers most of the body and is composed of the skin (the largest organ), nails, and subcutaneous tissue. Each component plays a vital role in protection, sensation, and homeostasis.

Anatomy of the Skin

Word Parts and Terminology

• integument/o-: skin

• -ary: pertaining to

• cutane/o-: skin

• -ous: pertaining to

Layers of the Skin

The skin consists of two primary layers:

• Epidermis: The thin, outermost layer made of epithelial tissue. It contains both living and dead cells, with the surface cells filled with keratin for protection and waterproofing.

• Dermis: The thick layer beneath the epidermis, composed of connective tissue, collagen, and elastin. It houses blood vessels, nerves, hair follicles, sebaceous glands, and sweat glands.

Epidermis Details

• Squamous layer: Upper part, contains dead keratinized cells.

• Basal layer: Deep part, contains living cells and melanocytes (produce melanin pigment).

• Melanocytes: All individuals have the same number, but melanin production varies. Sun exposure increases melanin; insufficient absorption leads to sunburn.

Dermis Details

• Contains collagen (firm, white protein) and elastin (elastic, yellow protein).

• Includes arteries, veins, nerves, hair follicles, sebaceous glands, and sweat glands.

• Dermatome: Area of skin sending sensory information to the spinal cord; also refers to a surgical instrument.

Glands of the Skin

• Sebaceous glands: Oil glands producing sebum, which moisturizes skin and hair.

• Sudoriferous glands: Sweat glands secreting sweat (water, sodium, waste) through skin pores.

Hair and Nails

• Hair: Covers most of the body; color determined by melanocytes; strength from keratin.

• Piloerection: Goosebumps caused by contraction of tiny muscles at hair follicle base.

• Nails: Consist of nail plate, root, lunula, cuticle, and nail bed. Nail growth originates from the root, forming the lunula and hardening into the plate.

Subcutaneous Tissue

• Loose connective tissue beneath the dermis, also called sub Q or subcu.

• Composed of adipose (fatty) tissue and lipocytes.

• Functions: Cushions, insulates, and protects internal organs; thickness varies with fat storage.

Physiology of the Integumentary System

Protection

• First line of defense against injury and infection.

• Acidic epidermis discourages microorganism growth.

• Keratin waterproofs skin; sweat and sebum contain antibodies and enzymes.

Repair

• Basal epidermal cells migrate to cover wounds.

• Deep wounds form blood clots and scabs; new cells fill in the wound.

Sensation

• Sensory receptors in the dermis detect touch, pressure, vibration, pain, and temperature.

• Nervous system interprets skin sensations.

Vitamin D Synthesis

• UV rays convert epidermal cholesterol to vitamin D.

• Vitamin D aids calcium absorption; sun exposure requirements vary by skin tone.

Thermoregulation

• Subcutaneous tissue stores fat and conserves heat.

• Piloerector muscles contract to generate heat.

• Sudoriferous glands produce sweat for cooling.

• Dermal blood vessels dilate to release heat.

Homeostasis

• Maintains balance and stability of body systems.

• Thermoregulation is a key aspect.

• Skin conditions can signal other medical issues.

Diseases and Disorders of the Skin

Edema

Edema is swelling caused by excess fluid in tissues. Pitting edema occurs when pressure leaves a deep indentation.

Types of Skin Lesions

Skin lesions are classified by appearance, contents, and cause. Common types include cysts, fissures, macules, papules, pustules, scales, vesicles, and wheals.

Lesion	Description	Color	Contents	Example
Cyst	Elevated circular mound	Skin color or erythema	Semisolid or partly fluid filled	Acne sebaceous cyst
Fissure	Small, cracklike crevice	Erythema	None, some fluid exudate	Dry, chapped skin
Macule	Flat circle	Pigmented brown or black	None	Freckle, age spot
Papule	Elevated	Skin color or erythema	Solid	Acne pimple
Pustule	Elevated	White top	Pus	Acne whitehead
Scale	Flat to slightly elevated, thin flake	White	None	Dandruff, psoriasis
Vesicle	Elevated with pointed top	Erythema with transparent top	Clear fluid	Herpes, chickenpox, shingles
Wheal	Elevated with broad, flat top	Erythema with pale top	Clear fluid	Insect bites, urticaria

Skin Color Conditions

• Insufficient melanin production leads to pale skin.

• Cyanosis: Bluish discoloration due to lack of oxygen.

• Necrosis: Tissue death from lack of blood supply.

• Vitiligo: Autoimmune disorder causing depigmentation.

Skin Injuries

• Burns: Partial-thickness burns cause separation of epidermis and dermis, leading to blisters.

• Rule of Nines: Tool for estimating burn surface area.

• Keloid: Excessive scar tissue formation.

• Laceration: Deep cut exposing subcutaneous tissue.

• Pressure injury: Caused by prolonged pressure, leading to tissue damage.

Skin Infections

• Herpes simplex type 1: Vesicles on lips.

• Shingles: Vesicles and crusts along a dermatome.

• Tinea capitis: Fungal infection of the scalp, also known as ringworm.

Allergic Skin Conditions

• Contact dermatitis: Skin reaction to irritants or allergens.

Benign Neoplasms of the Skin

• Hemangioma: Bright red lesion from dilated blood vessels.

• Nevus (mole): Pigmented, can be raised or flat, sometimes with hair.

• Port-wine stain: Flat, red nevus resembling spilled wine.

• Syndactyly: Fusion of skin and soft tissues between fingers or toes.

Malignant Neoplasms of the Skin

• Malignant melanoma: Asymmetrical, irregular edges, varying color, increasing size.

Autoimmune Disorders of the Skin

• Psoriasis: Commonly affects elbows and knees, characterized by red, scaly patches.

Diseases of the Sebaceous Glands

• Acne vulgaris: Papules and pustules triggered by increased sebaceous gland activity.

• Rosacea: Rose-colored erythema and dilated blood vessels, often affecting the face.

Diseases of the Nail

• Onychomycosis: Fungal infection causing discoloration, thickening, and deformation of nails.

Laboratory, Diagnostic, Medical, and Surgical Procedures

Botox Injection

• Botox is a diluted neurotoxin used for cosmetic and medical purposes.

Skin Examination

• Dermatologists use magnifying lenses to examine skin lesions, sometimes requiring biopsy.

Wound Closure

• Deep wounds may be closed with sutures or surgical glue.

Hypodermic Injection

• Injection technique involves delivering drugs into the subcutaneous tissue.

Punch Biopsy

• Punch biopsy removes a core of skin tissue for diagnostic purposes.

Liposuction

• Liposuction is a surgical procedure to remove fat from subcutaneous tissue for cosmetic reasons.

Summary Table: Types of Skin Lesions

Lesion	Description	Color	Contents	Example
Cyst	Elevated circular mound	Skin color or erythema	Semisolid or partly fluid filled	Acne sebaceous cyst
Fissure	Small, cracklike crevice	Erythema	None, some fluid exudate	Dry, chapped skin
Macule	Flat circle	Pigmented brown or black	None	Freckle, age spot
Papule	Elevated	Skin color or erythema	Solid	Acne pimple
Pustule	Elevated	White top	Pus	Acne whitehead
Scale	Flat to slightly elevated, thin flake	White	None	Dandruff, psoriasis
Vesicle	Elevated with pointed top	Erythema with transparent top	Clear fluid	Herpes, chickenpox, shingles
Wheal	Elevated with broad, flat top	Erythema with pale top	Clear fluid	Insect bites, urticaria

Key Medical Terminology

• Dermatology: Study of the skin

• Integumentary: Pertaining to the skin

• Cutaneous: Pertaining to the skin

• Melanocyte: Black pigment cell

• Piloerection: Action of hair standing up

• Subcutaneous: Beneath the skin

Formulas and Equations

Rule of Nines for Burn Assessment

The Rule of Nines is used to estimate the percentage of body surface area affected by burns:

• Head: 9%

• Chest: 9%

• Abdomen: 9%

• Each arm: 9%

• Genitals: 1%

• Each leg: 18%

• Back: 18%

Conclusion

The integumentary system is essential for protection, sensation, thermoregulation, and homeostasis. Understanding its anatomy, physiology, and common diseases is fundamental for medical terminology students and healthcare professionals.