BSC 2085 Exam Review: Integumentary, Skeletal, and Articular Systems (Ch. 5-8)

Ch. 5: The Integumentary System

Structure of the Skin

The skin is the largest organ of the body and consists of two main layers: the epidermis (superficial) and the dermis (deep). Beneath the dermis lies the hypodermis (subcutaneous layer), which is not technically part of the skin but anchors it to underlying tissues.

• Epidermis: Composed of stratified squamous epithelium; avascular; contains several cell types.

• Dermis: Made of connective tissue; contains blood vessels, nerves, glands, and hair follicles.

• Hypodermis: Consists mainly of adipose tissue; provides insulation and cushioning.

Cells of the Epidermis

• Keratinoctyes: Produce keratin, a protein that provides strength and waterproofing.

• Melanocytes: Produce melanin, the pigment responsible for skin color and UV protection.

• Langerhans (Dendritic) Cells: Immune cells that help protect against pathogens.

• Merkel (Tactile) Cells: Sensory receptors for touch.

Skin Color Components

• Melanin: Brown-black pigment produced by melanocytes; amount and type determine skin color.

• Carotene: Yellow-orange pigment from diet; accumulates in stratum corneum and hypodermis.

• Hemoglobin: Red pigment in blood; gives skin a pinkish hue, especially in light-skinned individuals.

Burn Degrees

• First-degree: Only epidermis is damaged; redness and pain (e.g., sunburn).

• Second-degree: Epidermis and upper dermis damaged; blisters form.

• Third-degree: Entire thickness of skin destroyed; area appears gray-white, cherry red, or blackened; usually no pain due to nerve destruction.

ABCDE Rule for Melanoma

The ABCDE rule helps identify malignant melanoma, a dangerous form of skin cancer:

• Asymmetry: Two sides of the pigmented area do not match.

• Border: Edges are irregular, ragged, or blurred.

• Color: Pigmentation is not uniform; may include shades of brown, black, tan, red, or blue.

• Diameter: Larger than 6 mm (about the size of a pencil eraser).

• Evolving: Changing in size, shape, or color.

Carcinoma Types

• Basal Cell Carcinoma: Most common, least malignant; arises from stratum basale.

• Squamous Cell Carcinoma: Arises from keratinocytes of stratum spinosum; can metastasize.

• Melanoma: Cancer of melanocytes; highly metastatic and dangerous.

Ch. 6: Bones and Skeletal Tissues

Types of Cartilage: Locations and Functions

• Hyaline Cartilage: Most abundant; found in articular surfaces, costal cartilages, nose, trachea, larynx; provides support and flexibility.

• Elastic Cartilage: Contains elastic fibers; found in external ear and epiglottis; maintains shape and flexibility.

• Fibrocartilage: Thick collagen fibers; found in intervertebral discs, pubic symphysis, menisci; resists compression and tension.

Functions of Bones

• Support: Framework for the body.

• Protection: Protects vital organs (e.g., skull, rib cage).

• Movement: Acts as levers for muscles.

• Mineral Storage: Reservoir for calcium and phosphate.

• Blood Cell Formation: Hematopoiesis in red marrow.

• Triglyceride Storage: Fat storage in yellow marrow.

Microscopic Bone Anatomy

• Osteon (Haversian System): Structural unit of compact bone; consists of concentric lamellae around a central canal.

• Lamellae: Layers of bone matrix.

• Lacunae: Small spaces housing osteocytes.

• Canaliculi: Tiny canals connecting lacunae for nutrient/waste exchange.

• Trabeculae: Lattice-like structures in spongy bone; align along lines of stress.

Cross-section of a Long Bone

• Diaphysis: Shaft; contains medullary cavity with yellow marrow.

• Epiphyses: Ends; contain spongy bone and red marrow.

• Metaphysis: Region between diaphysis and epiphysis; includes epiphyseal plate (growth plate).

• Periosteum: Outer fibrous covering; contains osteogenic cells.

• Endosteum: Lines internal bone surfaces.

Types of Bone (Shapes) and Examples

• Long Bones: Longer than wide (e.g., femur, humerus).

• Short Bones: Cube-shaped (e.g., carpals, tarsals).

• Flat Bones: Thin, flat, slightly curved (e.g., sternum, skull bones).

• Irregular Bones: Complex shapes (e.g., vertebrae, hip bones).

• Sesamoid Bones: Form within tendons (e.g., patella).

Bone Marrow Types, Locations, and Functions

• Red Marrow: Site of 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 fibrous membrane; forms flat bones (e.g., skull, clavicle).

• Endochondral Ossification: Bone replaces hyaline cartilage; forms most bones of the body.

Bone Cell Types

• Osteogenic Cells: Stem cells that differentiate into osteoblasts.

• Osteoblasts: Bone-forming cells; secrete bone matrix.

• Osteocytes: Mature bone cells; maintain bone matrix.

• Osteoclasts: Bone-resorbing cells; break down bone matrix.

Bone Fracture Types

• Simple (Closed): Bone breaks cleanly but does not penetrate skin.

• Compound (Open): Bone ends penetrate the skin.

• Comminuted: Bone fragments into three or more pieces.

• Greenstick: Incomplete break; common in children.

• Spiral: Ragged break due to twisting forces.

• Compression: Bone is crushed.

Ch. 7: The Skeleton

Axial vs. Appendicular Skeleton

• Axial Skeleton: Forms the long axis of the body; includes skull, vertebral column, and thoracic cage.

• Appendicular Skeleton: Includes limbs and girdles (pectoral and pelvic) that attach limbs to the axial skeleton.

Bone Identification and Articulations

• Each bone has a specific name and location; students should be able to identify bones on diagrams or models.

• Articulation: The point where two bones meet (joint); knowing which bones articulate is essential for understanding movement and structure.

Vertebrae Differentiation

• Cervical Vertebrae: Smallest; have transverse foramina; C1 (atlas) and C2 (axis) are specialized.

• Thoracic Vertebrae: Larger; have facets for rib articulation; spinous process points downward.

• Lumbar Vertebrae: Largest; thick, robust bodies; short, blunt spinous processes.

Ch. 8: Joints

Classification of Joints

• Structural Classification:

  • Fibrous: Bones joined by dense connective tissue; no joint cavity (e.g., sutures).

  • Cartilaginous: Bones joined by cartilage; no joint cavity (e.g., symphysis, synchondrosis).

  • Synovial: Bones separated by a fluid-filled joint cavity; most movable type.

• Functional Classification:

  • Synarthroses: Immovable joints.

  • Amphiarthroses: Slightly movable joints.

  • Diarthroses: Freely movable joints.

• Material Classification: Based on the type of tissue connecting the bones (see structural classification).

Synovial Joint Types

• Plane (Gliding): Flat surfaces; allow short gliding movements (e.g., intercarpal joints).

• Hinge: Cylindrical projection fits into a trough; movement in one plane (e.g., elbow).

• Pivot: Rounded end fits into a ring; rotation (e.g., proximal radioulnar joint).

• Oval articular surface fits into depression; movement in two planes (e.g., wrist).

• Saddle: Both surfaces have concave and convex areas; greater movement (e.g., thumb carpometacarpal joint).

• Ball-and-Socket: Spherical head fits into socket; multiaxial movement (e.g., shoulder, hip).

Knee Joint Structure

• Largest and most complex synovial joint.

• Composed of femur, tibia, and patella.

• Contains menisci (fibrocartilage pads), bursae, and several ligaments (e.g., ACL, PCL, MCL, LCL).

Bursae and Tendon Sheaths

• Bursae: Flattened sacs filled with synovial fluid; reduce friction between tissues.

• Tendon Sheaths: Elongated bursae that wrap around tendons; found in areas of high friction (e.g., wrist, ankle).

Synovial Joint Movements

• Gliding: Flat bone surfaces slide past each other.

• Angular Movements: Increase or decrease angle between bones (e.g., flexion, extension, abduction, adduction).

• Rotation: Bone turns around its own long axis (e.g., head, radius/ulna).

• Special Movements: Include supination, pronation, inversion, eversion, protraction, retraction, elevation, depression, opposition.

Axes of Movement

• Nonaxial: Slipping movements only (e.g., plane joints).

• Uniaxial: Movement in one plane (e.g., hinge, pivot joints).

• Biaxial: Movement in two planes (e.g., condyloid, saddle joints).

• Multiaxial: Movement in or around all three planes (e.g., ball-and-socket joints).

Joint Type	Axes of Movement	Example
Plane	Nonaxial	Intercarpal joints
Hinge	Uniaxial	Elbow
Pivot	Uniaxial	Proximal radioulnar joint
Condyloid	Biaxial	Wrist
Saddle	Biaxial	Thumb carpometacarpal joint
Ball-and-Socket	Multiaxial	Shoulder, hip

Example: The shoulder joint is a ball-and-socket synovial joint, allowing multiaxial movement such as flexion, extension, abduction, adduction, rotation, and circumduction.

Additional info: For exam preparation, students should be able to identify structures on diagrams, compare joint types, and understand the clinical significance of injuries (e.g., fractures, dislocations, ligament tears).