BSC 2085 Exam 2 Study Notes: Skin, Skeletal System, and Joints

Chapter 5: The Integumentary System

Layers and Structure of the Skin

The skin is the largest organ of the body and consists of multiple layers, each with distinct functions and cell types.

• Epidermis: The outermost layer, composed mainly of keratinocytes. It provides a barrier against pathogens and regulates water loss.

• Dermis: The middle layer, containing connective tissue, blood vessels, nerves, and appendages such as hair follicles and sweat glands.

• Subcutaneous Layer (Hypodermis): The deepest layer, consisting of adipose tissue that insulates and cushions the body.

Cell Types of the Epidermis:

• Keratinocytes: Produce keratin, a protective protein.

• Melanocytes: Produce melanin, which gives skin its color and protects against UV radiation.

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

• Merkel Cells: Sensory cells involved in touch sensation.

Structure of the Dermis:

• Contains collagen and elastin fibers for strength and elasticity.

• Houses blood vessels, nerves, hair follicles, and glands.

Changes in Skin Color:

• Skin color changes can indicate diseases such as jaundice (yellowing), cyanosis (bluish tint), or erythema (redness).

• Melanin production is affected by genetics, sun exposure, and certain disorders.

Hair and Nails:

• Hair is produced by follicles in the dermis; its growth and appearance can indicate health status.

• Nails are made of keratin and can show signs of systemic diseases (e.g., clubbing in respiratory disease).

Glands of the Skin:

• Sudoriferous (Sweat) Glands: Regulate temperature and excrete waste.

• Sebaceous (Oil) Glands: Lubricate skin and hair.

Types of Skin Cancer:

• Basal Cell Carcinoma

• Squamous Cell Carcinoma

• Melanoma (most dangerous)

Types of Burns:

• First-degree: Affects only the epidermis.

• Second-degree: Involves epidermis and part of dermis.

• Third-degree: Destroys both epidermis and dermis.

Aging of the Skin: With age, skin becomes thinner, less elastic, and more prone to injury and disease.

Chapter 6: The Skeletal System

Skeletal Cartilage and Bone Structure

The skeletal system provides support, protection, and movement. It consists of bones, cartilage, and connective tissues.

• Types of Skeletal Cartilage: Hyaline, elastic, and fibrocartilage.

• Functions of the Skeletal System: Support, protection, movement, mineral storage, blood cell formation.

Axial vs. Appendicular Skeleton:

• Axial Skeleton: Skull, vertebral column, and thoracic cage.

• Appendicular Skeleton: Limbs and girdles.

Bone Shapes:

• Long Bones: e.g., femur

• Short Bones: e.g., carpals

• Flat Bones: e.g., sternum

• Irregular Bones: e.g., vertebrae

Levels of Bone Structure:

• Gross Anatomy: Compact and spongy bone.

• Microscopic Anatomy: Osteons, lamellae, canaliculi.

Bone Cells:

• Osteoblasts: Build bone.

• Osteocytes: Maintain bone tissue.

• Osteoclasts: Break down bone.

Bone Formation:

• Endochondral Ossification: Bone forms from cartilage templates.

• Intramembranous Ossification: Bone forms directly from mesenchymal tissue.

Bone Growth:

• Interstitial Growth: Lengthening of bones.

• Appositional Growth: Thickening of bones.

Bone Remodeling: Continuous process of bone renewal and repair.

Bone Fractures: Classified by type (e.g., simple, compound) and repaired through healing stages.

Bone Disorders: Include osteoporosis, osteomalacia, and Paget's disease.

Chapter 7: The Axial and Appendicular Skeletons

Axial vs. Appendicular Skeleton

The skeleton is divided into axial and appendicular components, each with specific bones and functions.

• Axial Skeleton: Skull, vertebral column, thoracic cage.

• Appendicular Skeleton: Pectoral girdle, pelvic girdle, limbs.

Skull Anatomy and Function

• Major Bones: Frontal, parietal, temporal, occipital, sphenoid, ethmoid.

• Facial Bones: Maxilla, mandible, zygomatic, nasal, lacrimal, palatine, vomer, inferior nasal concha.

• Sutures: Immovable joints between skull bones (e.g., coronal, sagittal, lambdoid, squamous).

• Sinuses: Air-filled cavities that reduce skull weight and resonate voice.

Vertebral Column

• Regions: Cervical (7), thoracic (12), lumbar (5), sacral (5 fused), coccygeal (4 fused).

• Curvatures: Normal (cervical and lumbar lordosis, thoracic and sacral kyphosis); abnormal (scoliosis, kyphosis, lordosis).

Thoracic Cage

• Components: Sternum, ribs, thoracic vertebrae.

• Function: Protects heart and lungs, supports upper limbs.

Pectoral Girdle and Upper Limb

• Pectoral Girdle: Clavicle and scapula.

• Upper Limb: Humerus, radius, ulna, carpals, metacarpals, phalanges.

Pelvic Girdle and Lower Limb

• Pelvic Girdle: Ilium, ischium, pubis.

• Lower Limb: Femur, tibia, fibula, tarsals, metatarsals, phalanges.

• Differences between Male and Female Pelves: Female pelvis is wider and shallower for childbirth.

Development and Medical Conditions

• Skeleton Development: Ossification centers appear and bones grow and remodel with age.

• Medical Conditions: Herniated disc, carpal tunnel syndrome, cleft palate, developmental dysplasia of the hip.

Chapter 8: Joints (Articulations)

Classification and Features of Joints

Joints, or articulations, are sites where two or more bones meet. They are classified by structure and function.

• Structural Classification: Fibrous, cartilaginous, synovial.

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

Synovial Joints

• Features: Articular cartilage, joint cavity, synovial fluid, articular capsule, ligaments.

• Types of Synovial Joints: Plane, hinge, pivot, condyloid, saddle, ball-and-socket.

• Examples: Knee (hinge), shoulder (ball-and-socket), wrist (condyloid), thumb (saddle), atlas/axis (pivot).

Ranges of Motion

• Flexion, Extension, Abduction, Adduction, Rotation, Circumduction

Joint Disorders

• Inflammatory: Arthritis (e.g., rheumatoid arthritis)

• Degenerative: Osteoarthritis

• Other Disorders: Gout, bursitis

Table: Types of Synovial Joints and Examples

Type	Movement	Example
Plane	Gliding	Intercarpal joints
Hinge	Flexion/Extension	Elbow, knee
Pivot	Rotation	Atlas/axis, radioulnar joint
Condyloid	Flexion/Extension, Abduction/Adduction	Wrist
Saddle	Flexion/Extension, Abduction/Adduction	Thumb (carpometacarpal joint)
Ball-and-Socket	All movements	Shoulder, hip

Additional info: Academic context and terminology have been expanded for clarity and completeness. All major topics from the study guide are covered and grouped logically for exam preparation.