Overview of the Integumentary System

The integumentary system is the body's largest organ, consisting of the skin, hair, nails, and associated glands. It serves multiple vital functions, including protection, temperature regulation, and sensory perception.

• The skin is composed of three main layers: epidermis, dermis, and hypodermis
• Keratinocytes are the predominant cell type in the epidermis, with a 28-day life cycle
• The dermis contains blood vessels, lymphatics, receptors, and various glands
• The hypodermis (subcutaneous layer) provides energy storage and shock absorption

Vocabulary: Keratinocytes are the primary cell type in the epidermis, responsible for producing keratin, a protein that provides structural support and protection.

Highlight: The integumentary system plays a crucial role in protecting the body from external threats, regulating body temperature, and providing sensory information about the environment.

Common Skin Conditions

This section covers several skin diseases names and conditions affecting the integumentary system, including:

Raynaud's Phenomenon: A condition affecting blood supply to extremities during cold temperatures and stress. It causes color changes in fingers and toes (red, white, and blue) due to decreased blood flow and blood vessel constriction.

Scleroderma: A systemic connective tissue disease characterized by thickened, hardened skin, autoimmunity, vasculopathy, and fibrosis. It affects multiple organs, including the heart, lungs, gastrointestinal system, skin, and musculoskeletal system.

Psoriasis: A condition affecting the skin, nails, and joints, characterized by hyperproliferation of the epidermis, abnormal differentiation of epidermal keratinocytes, and inflammation. The life cycle of skin cells in psoriasis is reduced to 3-4 days instead of the normal 28 days.

Definition: Vasculopathy refers to any disorder of the blood vessels, which can affect blood flow and circulation.

Example: In psoriasis, the rapid turnover of skin cells leads to the formation of thick, scaly patches on the skin's surface.

Cellulitis and Burns

Cellulitis: A deep local bacterial infection of the lower dermis and subcutaneous tissue, typically caused by Staphylococcus aureus or Group A Streptococcus. Symptoms include redness, warmth, pain, and swelling in the affected area.

Burns: Injuries to the skin or other organic tissue caused by heat, radiation, electricity, friction, or chemical contact. Burns are classified into three degrees based on severity:

1. First-Degree Burns: Superficial burns affecting only the epidermis. The site is red, painful, and dry, with no blisters.

2. Second-Degree Burns: Partial-thickness burns affecting the epidermis and part of the dermis. The site appears red, blistered, swollen, and painful.

3. Third-Degree Burns: Full-thickness burns destroying the epidermis and dermis, potentially damaging underlying structures. The site appears white or charred, with no sensation due to destroyed nerve endings.

Vocabulary: Microvascular permeability refers to the ability of small blood vessels to allow substances to pass through their walls, which increases during the inflammatory response to burns.

Highlight: Treatment for burns depends on severity and may include aloe vera application, cool water, medications, and topical antiseptics and antibiotics.