Ch.3 Integumentary System

Overview of the Integumentary System

The integumentary system is a complex set of organs that includes the skin and its accessory structures such as hair, nails, sweat glands, and sebaceous glands. The skin is the largest organ of the human body and serves as a protective barrier between the internal environment and the external world.

• Skin Layers:

  • Epidermis: The outermost layer, composed of stratified squamous epithelial cells. It is avascular (lacks its own blood supply) and is primarily responsible for protection.

  • Dermis: The inner layer, made of connective tissue. It contains blood vessels, nerve endings, hair follicles, sweat glands, and sebaceous glands. The dermis binds the epidermis to deeper tissues.

  • Subcutaneous Layer (Hypodermis): A fatty layer that separates the dermis from deeper tissues, providing insulation and cushioning.

• Cutaneous Membrane: The collective term for the epidermis and dermis.

Functions of the Integumentary System

The integumentary system performs several vital functions essential for maintaining homeostasis and protecting the body.

• Protection: Acts as a barrier against chemicals, pathogens, and prevents loss of critical body fluids.

• Regulation: Controls body temperature through evaporation (sweating), vasoconstriction, and vasodilation.

• Secretion: Sebaceous glands secrete sebum to lubricate hair and skin; sweat glands aid in excretion of waste products.

• Sensation: Contains nerve endings that sense temperature, pain, touch, and pressure.

Accessory Structures of the Skin

Hair

Hair is composed of dead, keratinized cells and consists of a shaft (visible part) and a root (embedded in the follicle). The root receives nourishment from a loop of capillaries called the papilla. The arrector pili muscle, a small smooth muscle, contracts to cause goosebumps.

Sweat and Sebaceous Glands

• Sebaceous Glands: Secrete sebum to lubricate skin and hair. Sebum production increases during adolescence and decreases with age.

• Sweat Glands: Secrete sweat through ducts onto the skin surface, aiding in temperature regulation and excretion of waste. Both are classified as exocrine glands.

Nails

Nails are flat plates of hard keratin that cover the ends of fingers and toes. They are connected to deeper tissue by the nail bed. The cuticle is a soft tissue at the base of the nail, protecting the nail root. The lunula is the light-colored, half-moon-shaped area at the base of the nail.

Medical Terminology: Word Building for the Integumentary System

Medical terms related to the integumentary system are often constructed using combining forms, prefixes, and suffixes. Understanding these components aids in deciphering complex medical vocabulary.

Skin Characteristics and Colors

Pathological Conditions and Related Terminology

Many medical terms describe pathological conditions affecting the skin, hair, and nails. These terms often use specific combining forms to indicate the nature of the condition.

Common Diseases and Conditions

Diagnostic and Therapeutic Procedures

• Culture & Sensitivity: Growing and testing microorganisms for antibiotic sensitivity.

• Biopsy: Removal of tissue for examination and diagnosis.

• Frozen Section: Biopsy taken during surgery and frozen for rapid examination.

• Fungal Scrapings: Sampling of skin, hair, or nail from an infected area to diagnose fungal infections.

• Debridement: Removal of dead or infected tissue to promote healing.

• Curettage: Specific form of debridement using a curette (scraper).

Pharmacology Related to the Integumentary System

• Anticoagulant: Prevents blood from clotting.

• Antineoplastic: Slows the growth of malignant tumors.

• Agonist: Binds to a cell and triggers a response.

• Antagonist: Binds to a cell and blocks a response.

• Bioavailability: The proportion of medication that enters the bloodstream and causes a desired effect.

• Corticosteroids: Synthetic anti-inflammatory medications.

Summary Table: Key Combining Forms and Their Meanings

Additional info: This guide covers the essential structure, function, terminology, and pathology of the integumentary system, providing a foundation for further study in medical terminology and clinical practice.