a&p review

Burn Types and Severity

Burn Degrees:

• Third Degree Burn: Most serious type of burn, destroying all layers of skin (epidermis, dermis, and subcutaneous tissue) and can damage underlying tissues, nerves, and even muscles. These burns often appear white, charred, or leathery and can result in severe pain or numbness depending on nerve damage.

• Second Degree Burn: Characterized by blisters, swelling, and redness, this burn affects the epidermis and part of the dermis. Pain can be significant, and healing typically occurs in 2-3 weeks, but may lead to scarring and discoloration.

• First Degree Burn: Presents as redness and minor pain, affecting only the outer layer of skin (epidermis). Healing usually occurs within a few days without scarring, although peeling may occur as the skin regenerates.

Membranes and Layers

• Pleura: Membrane covering the lungs, consisting of two layers (visceral and parietal). It reduces friction during respiration and facilitates lung expansion and contraction.

• Pericardium: Membrane surrounding the heart that provides protection and contains pericardial fluid to minimize friction as the heart beats.

• Peritoneum: Membrane covering the abdominal cavity and organs, allowing for movement and functioning while protecting and supporting the abdominal organs.

• Visceral Layer: Closest layer to the organ, sensitive to pain and pressure.

• Parietal Layer: Outer layer, which attaches to the abdominal wall and diaphragm, serving as a protective barrier.

• Fluid Between Layers: Serves as a lubricant for aiding organ movement.

• Ascites: Fluid buildup in the peritoneal cavity that can indicate disease and cause abdominal distension.

• Edema: General fluid buildup in tissues, often occurring after injury or inflammation, such as twisting an ankle.

Joint Anatomy

• Tibia: Main bone in the lower leg, supports weight-bearing activities.

• Femur: Longest bone in the body, superior to the tibia, crucial for walking and running.

• Ligament: Connects bone to bone, made of dense connective tissue, providing stability and strength to joints.

• Fibrous Capsule: Encases the joint, providing integrity and protection.

• Synovial Membrane: Secretes synovial fluid into the joint space to lubricate and nourish articulating cartilage.

• Bursa: Sac filled with synovial fluid that reduces friction between tissues such as tendons, ligaments, and bones around joints.

Skin and Glands

Layers of Epidermis:

1. Stratum Corneum: Outermost layer, composed of dead keratinized cells, providing a barrier to water loss and environmental harm.

2. Stratum Granulosum: Contains granules that release lipids, contributing to waterproofing the skin.

3. Stratum Spinosum: Provides strength and flexibility to the skin through interconnected cells.

4. Stratum Basale: Deepest layer where new skin cells are generated; contains melanocytes that produce melanin.

5. Extra Layer: Stratum Lucidum, found in thick skin areas (palms and soles), providing an additional layer of protection.

Glands:

• Sweat Glands:

  • Eccrine: Distributed widely, these glands respond to body temperature for thermal regulation.

  • Apocrine: Limited to certain areas (e.g., armpits, groin), these glands respond to emotional stress and produce a thicker secretion.

• Sebaceous Glands: Oil glands that secrete sebum to keep skin hydrated and protect against bacterial growth.

• Melanin: Pigment produced by melanocytes that gives skin its color and protects from UV radiation damage by absorbing harmful rays.

Skin Conditions and Responses

• Malignant Melanoma: The most dangerous form of skin cancer, originating from melanocytes; it is known for its ability to metastasize and requires early detection for effective treatment.

• Erythema: Redness of the skin resulting from increased blood flow, often due to embarrassment, inflammation, or fever, which can indicate underlying health issues.

• Hives: Allergic reaction characterized by itchy welts on the skin; can be triggered by various allergens or stress and often treated with antihistamines.

Bone Anatomy

• Vertebral Fractures:

  • Compression Fracture: Typically occurs in osteoporotic vertebral bodies; results in loss of height of the vertebra.

  • Curvature Changes: Compression fractures may lead to abnormal spinal curvature, such as kyphosis or lordosis, affecting posture and balance.

Ribs Classification

• True Ribs: Ribs 1-7 that connect directly to the sternum, providing protection to the thoracic cavity.

• False Ribs: Ribs 8-10 that connect to the sternum through cartilage, providing flexibility and movement.

• Floating Ribs: Ribs 11-12 are not attached to the sternum at all; they provide padding and protection for the kidneys.

General Exam Preparation Tips

• Understand the Rule of Nines for burn assessment to estimate total body surface area affected. Each arm = 9%, each leg = 18%.

• Be familiar with critical burn percentages: 10% for third-degree burns and 2.5% for second-degree burns indicate higher risk of complications.

• Review the ABCDE rules (Asymmetry, Border, Color, Diameter, Evolving) for skin cancer detection to identify abnormal moles and lesions.