Chapter 5: The Integumentary System

Skin Structure and Function

The skin is the largest organ of the body and serves as a protective barrier. It is composed of multiple layers, each with distinct functions.

• Tissue Types: The skin consists of the epidermis (outer layer) and dermis (inner layer). The hypodermis (subcutaneous layer) lies beneath the dermis and is primarily composed of adipose tissue.

• Functions of Skin: Protection, sensation, temperature regulation, excretion, and synthesis of vitamin D.

• Layers of Epidermis: Includes (from superficial to deep): stratum corneum, stratum lucidum (only in thick skin), stratum granulosum, stratum spinosum, and stratum basale.

• Dermis: Contains connective tissue, blood vessels, nerves, hair follicles, and glands.

• Hypodermis: Provides insulation and energy storage.

Hair and Nails

• Hair: Made of keratin; functions include protection and sensation.

• Hair Structure: Shaft, root, follicle, bulb. Each part has a specific role in hair growth and maintenance.

• Nails: Composed of keratin; protect the distal phalanges and aid in manipulation of objects.

Glands of the Skin

• Sudoriferous (Sweat) Glands: Eccrine (widely distributed, regulate temperature) and apocrine (associated with hair follicles, active after puberty).

• Sebaceous Glands: Secrete sebum to lubricate skin and hair.

• Comparison: Eccrine glands are more numerous and function in thermoregulation; apocrine glands are found in specific areas and become active during emotional stress.

Burns and Skin Cancer

• Burns: Classified by depth: first-degree (epidermis), second-degree (epidermis and part of dermis), third-degree (full thickness). Severe burns are life-threatening due to fluid loss and infection.

• Skin Cancer: Major types include basal cell carcinoma, squamous cell carcinoma, and melanoma. Melanoma is the most dangerous due to its high rate of metastasis.

• Cell Type Involved: Basal cell (basal cell carcinoma), squamous cell (squamous cell carcinoma), melanocytes (melanoma).

Chapter 6: Cartilage and Bone Tissue

Cartilage

Cartilage is a flexible connective tissue found in various parts of the body. It provides support and cushioning.

• Properties: Avascular, slow to heal, composed of chondrocytes in lacunae.

• Types: Hyaline (most common, found in joints), elastic (ear, epiglottis), fibrocartilage (intervertebral discs, pubic symphysis).

• Growth: Appositional (surface) and interstitial (within tissue).

Bones

• Bone Cells: Osteoblasts (build bone), osteocytes (maintain bone), osteoclasts (break down bone).

• Bone Development: Intramembranous ossification (flat bones) and endochondral ossification (long bones).

• Bone Structure: Compact bone (dense), spongy bone (trabecular).

• Bone Healing: Hematoma formation, fibrocartilaginous callus, bony callus, bone remodeling.

• Bone Diseases: Osteoporosis, osteomalacia, Paget's disease.

Chapter 7: The Axial and Appendicular Skeleton

Axial Skeleton

• Components: Skull, vertebral column, thoracic cage.

• Skull: Contains foramina for nerves and blood vessels.

• Vertebral Column: Cervical, thoracic, lumbar, sacral, coccygeal regions; intervertebral discs provide cushioning.

• General Movements: Flexion, extension, rotation, lateral bending.

• Disorders: Scoliosis, herniated disc, spina bifida.

Appendicular Skeleton

• Components: Pectoral girdle, upper limbs, pelvic girdle, lower limbs.

• Review: Major bones and their functions, changes throughout life.

• Disorders: Fractures, dislocations, osteoporosis.

Chapter 9: Joints (Articulations)

Classification and Properties of Joints

Joints are classified by structure and function. They allow movement and provide stability.

• Structural Classes: Fibrous, cartilaginous, synovial.

• Functional Classes: Synarthroses (immovable), amphiarthroses (slightly movable), diarthroses (freely movable).

Synovial Joints

• Components: Articular cartilage, joint cavity, synovial fluid, ligaments, nerves, blood vessels.

• Movements: Gliding, angular, rotation, special movements (e.g., pronation, supination).

• Selected Joints:

  • Temporomandibular joint

  • Sternoclavicular joint

  • Glenohumeral (shoulder) joint

  • Elbow joint

  • Hip joint

  • Knee joint

• Ligaments: Provide stability; examples include anterior cruciate ligament (ACL) in the knee.

• Disorders: Arthritis, dislocations, sprains.

Chapter 10: Muscle Tissue

Properties and Types of Muscle Tissue

Muscle tissue is specialized for contraction and movement. There are three types: skeletal, cardiac, and smooth.

• Skeletal Muscle: Voluntary, striated, attached to bones.

• Cardiac Muscle: Involuntary, striated, found in the heart.

• Smooth Muscle: Involuntary, non-striated, found in walls of hollow organs.

Muscle Fiber Anatomy and Contraction

• Muscle Fiber Structure: Sarcolemma, sarcoplasm, myofibrils, sarcomeres.

• Sliding Filament Model: Muscle contraction occurs when actin and myosin filaments slide past each other. Equation: $\text{Force} = \text{Cross-bridge number} \times \text{Force per cross-bridge}$

• Neuromuscular Junction: Site where motor neuron stimulates muscle fiber.

• Mechanisms of Contraction and Relaxation: Involves calcium ions, ATP, and regulatory proteins.

• Types of Skeletal Muscle Fibers: Slow-twitch (Type I), fast-twitch (Type IIa and IIb).

• Disorders: Muscular dystrophy, myasthenia gravis.

Microscopic Anatomy of Muscle Tissue

• Structures: Myofibrils, sarcomeres, T-tubules, sarcoplasmic reticulum.

• Contraction: Involves interaction of actin, myosin, troponin, and tropomyosin.

Additional info: This study guide covers the major topics for an Anatomy & Physiology exam, including skin, cartilage, bone, joints, and muscle tissue. Students should review definitions, structures, functions, and disorders for each system.