A&P Skeletal Tissues (types of bone)

Chapter Overview: Skeletal System (Chapters 11-17)

• Focus Areas: Understanding skeletal tissues, bones, articulations (joints), and the muscular system.

Chapter 11: Skeletal Tissues

• Bones as Organs:

  • Bones act as organs of the skeletal system and are crucial for support and protection.

  • They are part of multiple systems, contributing to movement and support structures.

  • Bones form the body's framework, influencing shape, alignment, and positioning.

• Connective Tissues: Ligaments vs. Tendons:

  • Tendons: Connect muscle to bone or to other structures (e.g., skin).

  • Ligaments: Connect bone to bone and help define joints; examples include MCL, ACL, and Tommy John ligament.

• Functions of Bones:

  • Support: Creates the body’s framework.

  • Protection: Enclose vital organs (e.g., rib cage protects heart and lungs, skull protects the brain).

  • Movement: Acts as levers for muscle contraction to facilitate movement.

  • Mineral Storage: Stores minerals like calcium and phosphorus.

  • Hematopoiesis: Blood cell production occurs in the bone marrow.

Anatomy of the Skeletal System

• Overview of Bones: 206 bones in the human body; focus on major bones and their unique features.

• Skeletal Mass Classification:

  • Axial Skeleton: Comprises bones in the trunk and torso.

  • Appendicular Skeleton: Comprises bones extending from the trunk (e.g., limbs).

Bone Classification by Shape

• Long Bones:

  • Characteristics: Cylinder-shaped, taller than wide.

  • Examples: Femur, humerus, tibia.

• Short Bones:

  • Characteristics: Box-like, equal height, width, and depth.

  • Examples: Carpal bones in the wrist, tarsals in the foot.

• Flat Bones:

  • Characteristics: Broad, sheet-like, not thick.

  • Examples: Sternum, skull bones.

• Irregular Bones:

  • Do not fit other classifications due to unique shapes.

  • Examples: Vertebrae, scapula.

• Sesamoid Bones:

  • Characteristics: Seed-like, grow within tendons.

  • Example: Patella (kneecap) grows within the patellar tendon.

Patella: Unique Functionality

• Function:

  • Assists in knee extension; allows quadriceps muscles to efficiently contract by acting as a fulcrum.

  • Important in maintaining stability of knee motion.

• Development:

  • Infants are born without kneecaps; develop as they grow.

Bone Structure and Composition

• Types of Bone Tissue:

  • Compact Bone: Dense, solid layer that forms the outer structure of bones. Contains cells like osteocytes and osteoblasts.

  • Cancellous (Spongy) Bone: Located beneath compact bone; supports bone marrow and soft tissues. Characterized by trabeculae that provide structural support.

• Function of Different Bone Types: Each bone type is oriented to maximize its functional purpose within the skeletal system.