Ch. 5: Integumentary System

Structure of Skin

The skin is the largest organ of the body, composed of two main layers: the epidermis and dermis, with a subcutaneous layer beneath.

• Epidermis: Outermost layer, primarily made of keratinized stratified squamous epithelium.

• Dermis: Deeper connective tissue layer containing blood vessels, nerves, and accessory structures.

• Subcutaneous (hypodermis): Not technically part of the skin, but connects skin to underlying tissues and stores fat.

Burn Degrees

Burns are classified by depth and tissue involvement.

• First-degree: Affects only the epidermis; redness and pain (e.g., mild sunburn).

• Second-degree: Involves epidermis and part of dermis; blisters and more severe pain.

• Third-degree: Destroys both epidermis and dermis; may extend into subcutaneous tissue; skin may appear white, charred, or leathery.

ABCDE Rule for Melanoma

The ABCDE rule helps identify potential melanomas (skin cancers):

• Asymmetry

• Border irregularity

• Color variation

• Diameter > 6 mm

• Evolving (changing in size, shape, or color)

Carcinoma Types

• Basal cell carcinoma: Most common, least dangerous; arises from basal cells in the epidermis.

• Squamous cell carcinoma: Arises from keratinocytes; can metastasize if not treated.

• Melanoma: Arises from melanocytes; most dangerous due to high metastatic potential.

Cells of the Epidermis

• Keratinocytes: Produce keratin, a protective protein.

• Melanocytes: Produce melanin pigment.

• Langerhans cells: Immune defense.

• Merkel cells: Sensory receptors for touch.

Skin Color Components

• Melanin: Brown-black pigment produced by melanocytes.

• Carotene: Yellow-orange pigment from diet.

• Hemoglobin: Red pigment in blood, visible through skin.

Ch. 6: Skeletal System - Bone Tissue

Types of Cartilage: Locations and Functions

• Hyaline cartilage: Most common; found in nose, trachea, articular surfaces; provides support and flexibility.

• Elastic cartilage: External ear, epiglottis; maintains shape and flexibility.

• Fibrocartilage: Intervertebral discs, pubic symphysis; resists compression and tension.

Functions of Bones

• Support for the body

• Protection of internal organs

• Movement (leverage for muscles)

• Mineral storage (calcium, phosphate)

• Blood cell production (hematopoiesis in marrow)

• Triglyceride storage (yellow marrow)

Microscopic Bone Anatomy

• Cross-section of a long bone: Shows compact bone surrounding medullary cavity, with spongy bone at the ends.

• Compact bone: Dense, organized into osteons (Haversian systems).

• Spongy bone: Lattice-like trabeculae, contains red marrow.

Types of Bones (Shapes) and Examples

• Long bones: Femur, humerus

• Short bones: Carpals, tarsals

• Flat bones: Skull, ribs, sternum

• Irregular bones: Vertebrae, pelvis

• Sesamoid bones: Patella

Bone Marrow Types, Locations, and Functions

• Red marrow: Hematopoiesis; found in spongy bone of flat bones and epiphyses of long bones.

• Yellow marrow: Fat storage; found in medullary cavity of long bones.

Ossification Processes

• Intramembranous ossification: Bone develops from mesenchymal tissue (e.g., flat bones of skull).

• Endochondral ossification: Bone replaces hyaline cartilage (e.g., long bones).

Bone Cell Types

• Osteoblasts: Build bone matrix.

• Osteocytes: Mature bone cells, maintain matrix.

• Osteoclasts: Break down bone matrix.

Bone Fracture Types

• Simple (closed): Bone breaks but does not pierce skin.

• Compound (open): Bone pierces skin.

• Comminuted: Bone shatters into several pieces.

• Greenstick: Incomplete break, common in children.

Ch. 7: The Axial and Appendicular Skeleton

Bone Identification and Articulation

• Be able to locate and name each bone in the human skeleton.

• Know which bones articulate (form joints) with each other.

Axial vs. Appendicular Skeleton

• Axial skeleton: Skull, vertebral column, rib cage; supports and protects organs of head, neck, and trunk.

• Appendicular skeleton: Limbs and girdles; enables movement.

Vertebrae Differentiation

• Recognize differences among cervical, thoracic, and lumbar vertebrae based on structure and location.

• Identify bones individually and/or on a skeleton (using diagrams).

Ch. 8: Articulations (Joints)

Joint Classifications

• Structural: Based on material binding bones (fibrous, cartilaginous, synovial).

• Functional: Based on movement (synarthrosis - immovable, amphiarthrosis - slightly movable, diarthrosis - freely movable).

• Material: Type of connective tissue involved.

Synovial Joint Types

• Plane (gliding): Intercarpal joints

• Hinge: Elbow, knee

• Pivot: Atlantoaxial joint

• Wrist

• Saddle: Thumb (carpometacarpal joint)

• Ball-and-socket: Shoulder, hip

Knee Joint Diagrams

• Understand the anatomy of the knee joint, including bones, ligaments, menisci, and synovial cavity.

Bursae and Tendon Sheaths

• Bursae: Fluid-filled sacs that reduce friction between moving structures.

• Tendon sheaths: Elongated bursae that wrap around tendons.

Synovial Joint Movements

• Types of movement: flexion, extension, abduction, adduction, rotation, circumduction, etc.

Axes of Movement

• Nonaxial: No axis (gliding movements)

• Uniaxial: Movement in one plane (hinge, pivot)

• Biaxial: Movement in two planes (condyloid, saddle)

• Multiaxial: Movement in three or more planes (ball-and-socket)