skeletalsystem

Lesson 1: Function and Role

Learning Objectives

  • Explain the functions of the skeletal system.

  • Identify bones of the skeletal system.

  • Discuss interaction between the skeletal system and other body systems.

  • Review directional terms common to the skeletal system.

The Amazing Skeletal System

  • Supports movement, communication, and functions of life through bones.

  • At birth: 300 bones; adult skeleton has 206 as some bones fuse.

  • Function and size variation:

    • Smallest bones (middle ear) can fit on a dime and transmit sound.

    • Largest bone (femur) bears great weight (up to 4,000 Newtons).

  • Bones are incredibly strong (4x stronger than concrete), self-repairing post-fracture.

Functions of the Skeletal System

Primary Functions

  1. Protects Organs:

    • Hard bone structure shields vital organs (e.g., skull for the brain).

  2. Supports the Body:

    • Provides shape and structure to the body.

  3. Helps with Movement:

    • Acts as levers for muscles to create movement.

  4. Stores Minerals:

    • Bones store calcium and phosphorus, vital for other body systems.

  5. Produces Blood Cells:

    • Red bone marrow in bones facilitates hematopoiesis (blood cell formation).

  6. Stores Fat:

    • Yellow bone marrow acts as an energy reserve.

Components of the Skeletal System

  • Cartilage: Avascular tissue that cushions joints.

  • Ligaments: Connect bones to each other, stabilizing joints.

  • Tendons: Connect muscles to bones, facilitating movement.

Directional Terms

  • Anterior vs. Posterior: Front vs. back (e.g., kneecap is anterior to leg).

  • Superior vs. Inferior: Above versus below (e.g., head is superior to neck).

  • Medial vs. Lateral: Towards the midline vs. away from midline (e.g., nose is medial).

  • Proximal vs. Distal: Closer to trunk vs. further from trunk (e.g., elbow is distal to shoulder).

Lesson 2: Calcium Homeostasis

Learning Objectives

  • Identify importance of calcium.

  • Explain calcium absorption.

  • Discuss calcium storage.

  • Describe calcium homeostasis.

Homeostasis and Calcium

  • Homeostasis maintains mineral balance and bone remodeling.

  • Calcium's Role in the Body:

    • Essential for muscle/nervous function, heart regulation, and blood clotting.

  • Calcium is absorbed via diet (milk, leafy greens) with vitamin D.

Calcium Regulation

  • Low Calcium Levels:

    • Parathyroid hormone (PTH) increases blood calcium through stimulation of bone resorption, increases vitamin D synthesis.

  • High Calcium Levels:

    • Calcitonin (from thyroid) decreases blood calcium through bone formation and kidney absorption alterations.

Lesson 3: Maintaining Healthy Bones

Learning Objectives

  • Importance of healthy bones.

  • Impact of diet and exercise.

  • Proper body mechanics.

Importance of Healthy Bones

  • Bones are dynamic, undergoing remodeling; outpace formation in youth and, post-peak mass, resorption increases.

  • Risk of fracture due to aging-related loss of bone density (osteoporosis).

Bone Health: Diet

  • Calcium's importance; primary source through diet (milk, cheese, fortified foods).

  • Vitamin D aids calcium absorption; produced via sun exposure.

Bone Health: Exercise

  • Weight-bearing activities strengthen bones; lack of stress leads to bone loss (e.g., astronauts).

Proper Body Mechanics

  • Good posture and mechanics prevent spinal issues. Recommendations include maintaining a neutral spine.

Lesson 1: Bone Classifications

Learning Objectives

  • Identify bone composition and classification by shape.

Composition of Bones

  • Bone consists of 12-15% of body weight, divided into organic (collagen) and inorganic (calcium-phosphorus) components.

Classifications by Shape

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

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

  3. Flat Bones: Thin/broad (e.g., cranial bones).

  4. Irregular Bones: Unusual shapes (e.g., vertebrae).

  5. Sesamoid Bones: Small bones within tendons (e.g., patella).

  6. Sutural Bones: Tiny bones between cranial bones.

Lesson 2: Overview of the Skeletal System

Learning Objectives

  • Describe skeletal system divisions.

  • Define axial and appendicular skeleton bones.

  • Classify articulations.

Divisions of the Skeletal System

  • Axial Skeleton: Forms torso (skull, vertebral column, rib cage) for organ protection.

  • Appendicular Skeleton: Forms extremities, provides support/motion.

Axial Skeleton Details

  • Total of 80 bones; includes cranial (8), facial (14), thoracic, vertebrae (26).

Appendicular Skeleton Details

  • Approximately 126 bones including girdles and upper/lower extremities.

Lesson 1: Gross Anatomy

Learning Objectives

  • Define gross anatomy and bone types.

Structure of Long Bone

  • Diaphysis: Shaft of long bone.

  • Epiphysis: Ends of long bone, covered in cartilage.

  • Metaphysis: Growth plate area.

Layers of Long Bone

  • Periosteum: Outer fibrous layer.

  • Compact Bone: Dense outer layer.

  • Spongy Bone: Inner layer with a honeycomb structure.

  • Bone Marrow: Red (blood cell production) and yellow (fat storage).

Lesson 2: Bone Cells

Learning Objectives

  • Identify and describe bone cell types.

Types of Bone Cells

  1. Osteogenic Cells: Stem cells that differentiate into other cell types.

  2. Osteoblasts: Bone-forming cells.

  3. Osteocytes: Mature bone cells maintaining bone matrix.

  4. Osteoclasts: Bone-resorbing cells breaking down bone.

Lesson 3: Bone Tissue

Learning Objectives

  • Identify types of bone tissue.

Types of Bone Tissue

  • Compact Bone: Dense outer layer.

  • Spongy Bone: Lattice structure for weight support.

  • Subchondral Bone: Located below cartilage in joints.