BSC 2085 Exam Review: Chapters 5–8 (Integumentary, Skeletal, and Articular Systems)

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 tissue), which is not technically part of the skin but anchors it to underlying structures.

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

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

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

Burn Degrees

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

• Second-degree burns: Involve the epidermis and part of the dermis; cause redness, pain, and blistering.

• Third-degree burns: Destroy the entire thickness of the skin; skin may appear white, gray, or blackened; usually painless due to nerve destruction.

ABCDE Rule for Melanoma

The ABCDE rule helps identify potential melanomas (a type of skin cancer):

• Asymmetry: One half of the mole does not match the other.

• Border irregularity: Edges are ragged or blurred.

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

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

• Evolving: Changes in size, shape, or color over time.

Types of Carcinomas

• Basal cell carcinoma: Most common, least malignant; arises from stratum basale.

• Squamous cell carcinoma: Arises from keratinocytes of the stratum spinosum; can metastasize.

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

Cells of the Epidermis

• Keratinoctyes: Produce keratin; most abundant cell type.

• Melanocytes: Produce melanin pigment; protect against UV radiation.

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

• Merkel (tactile) cells: Sensory receptors for touch.

Skin Color Components

• Melanin: Brown to black pigment produced by melanocytes.

• Carotene: Yellow to 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.

Ch. 6: Bones and Skeletal Tissues

Types of Cartilage: Locations and Functions

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

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

• Fibrocartilage: Highly compressible; found in intervertebral discs, pubic symphysis, and menisci; resists tension and pressure.

Functions of Bones

• Support for the body and soft organs

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

• Movement (leverage for muscles)

• Mineral storage (especially calcium and phosphate)

• Blood cell formation (hematopoiesis in red marrow)

• Triglyceride (fat) storage in yellow marrow

• Hormone production (osteocalcin)

Microscopic Bone Anatomy

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

• Lacunae: Small spaces housing osteocytes.

• Canaliculi: Tiny channels connecting lacunae for nutrient and 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 of the bone; 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.

Compact vs. Spongy Bone Microstructure

• Compact bone: Dense; contains osteons; provides strength.

• Spongy bone: Porous; contains trabeculae; found in epiphyses and flat bones.

Types of Bones (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: Stores fat; found in medullary cavity of long bones in adults.

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 tissue.

• 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: Bone breaks incompletely (common in children).

• Spiral: Ragged break due to twisting forces.

• Compression: Bone is crushed (common in vertebrae).

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; bones articulate (form joints) with specific neighboring bones.

• Examples: The humerus articulates with the scapula at the shoulder and with the radius and ulna at the elbow.

Vertebrae Differentiation

• Cervical vertebrae (C1–C7): Smallest; have transverse foramina.

• Thoracic vertebrae (T1–T12): Articulate with ribs; have long, downward-pointing spinous processes.

• Lumbar vertebrae (L1–L5): Largest; have thick, short spinous processes.

Bone Identification on Skeleton

• Ability to identify bones visually and on diagrams is essential for anatomy study.

Ch. 8: Joints

Classifications of Joints

• Structural classification: Based on material binding bones and presence of joint cavity.

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

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

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

• Functional classification: Based on degree of movement.

  • Synarthroses: Immovable joints.

  • Amphiarthroses: Slightly movable joints.

  • Diarthroses: Freely movable joints.

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 a 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 a socket; multiaxial movement (e.g., shoulder, hip).

Knee Joint Anatomy

• The knee is a complex synovial joint involving the femur, tibia, and patella.

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

Bursae and Tendon Sheaths

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

• Tendon sheaths: Elongated bursae that wrap around tendons; reduce friction.

Synovial Joint Movements

• Gliding: Flat bone surfaces slide over one another.

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

• Rotation: Bone turns around its own long axis.

• Special movements: Include supination, pronation, inversion, eversion, protraction, retraction, elevation, and depression.

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).