Osseous Tissue - 1

Introduction

  • Upcoming exam details discussed.

    • Contains 18 lab questions.

    • Exam scheduled for two weeks from today.

  • Split format: Lecture and lab, requiring setup and teardown.

Osseous Tissue (Bone)

  • Definition of osseous tissue as the tissue forming bones.

  • Types of tissues involved in the skeletal system: bone and cartilage.

  • The following areas will be covered:

    • Types of bones

    • Function of bones

    • Bone growth and healing

Bone Basics

  • Skeletal system includes:

    • Bones: The main focus in lab.

    • Cartilage: Transition from cartilage to bone (no need to focus on ligaments).

Functions of the Skeletal System

  • Support: Provides structural framework and shape.

  • Mineral Storage: Primarily calcium storage, along with lipids in yellow marrow.

  • Blood Cell Production: Occurs in red bone marrow but not deeply covered in this chapter.

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

  • Movement: Functions as levers for muscles.

Bone Density

  • Peak bone density:

    • Males: ~21 years old

    • Females: ~18 years old

  • Gradual decline of bone density post-peak due to hormonal changes.

Stages of Bone Development

  • Growth starts with cartilage, which eventually remodels into bone.

  • Discussion of the maturation process of bones and the importance of maintenance throughout life.

Classification of Bones

  • Bone count: Average of 206 bones in adults (born with ~270 bones, some fuse during growth).

    • Long Bones: E.g., femur, phalanges.

    • Flat Bones: E.g., skull, sternum.

    • Suture Bones: Small irregular bones in the skull.

    • Irregular Bones: E.g., vertebrae.

    • Short Bones: E.g., wrist, ankle bones.

    • Sesamoid Bones: E.g., patella; these can vary in individuals.

Bone Structure

  • Long bones consist of:

    • Diaphysis: Shaft of the long bone, typically hollow.

    • Epiphysis: Ends of the long bone, contains spongy bone.

  • Compact vs. spongy bone:

    • Compact Bones: Dense structure; withstands compressive forces.

    • Spongy (Cancellous) Bones: Lighter and found at the ends where more flexibility is required.

Bone Tissue: Osseous Tissue

  • Living tissue composed of matrix, collagen fibers, calcium, and minerals.

  • Cells in bone tissue:

    • Osteocytes: Mature bone cells residing in lacunae, can remodel.

    • Osteoblasts: Immature cells producing bone matrix.

    • Osteoclasts: Cells responsible for breaking down bone tissue.

    • Osteoprogenitor Cells: Stem cells that develop into osteoblasts.

Bone Homeostasis

  • Importance of balance between osteoblast (building) and osteoclast (breaking down) activity.

  • Role of exercise, especially weight-bearing activities, in promoting bone health and remodeling.

Summary on Bones and Exercise

  • Maintaining bone density requires constant remodeling and balance between bone formation and resorption.

  • Weight-bearing exercises stimulate osteoblast activity, leading to stronger bones.

Conclusion

  • Emphasis on the importance of ongoing learning in lab sessions.

  • Encouragement to ask questions and engage actively in the lab and upcoming classes.