Comp 2. Lecture 3 of-s1-full

Introduction

• Lecture Topic: Connective Tissue

• Traditional Land Acknowledgement to elders past, present, and future.

• Student Learning Outcomes (SLOs):

  • Review histology and primary tissue types.

  • Focus on connective tissue, its components, classes, and distribution in the body.

Characteristics of Connective Tissue

• Most abundant and widely distributed primary tissue in the body.

• Composition:

  • Few cells compared to a large volume of extracellular matrix (ECM).

  • Extracellular Matrix: Key difference from epithelial tissue.

• Diversity:

  • Varies in structure and function based on classification and location.

Functions of Connective Tissue

• Supports the body in various ways:

  • Connection: Binds structures; e.g., capsules around organs.

  • Support: Provides strength and stability; e.g., bone and cartilage.

  • Protection and Insulation: E.g., adipose tissue acts as cushioning and heat insulation.

  • Compartmentalization: Organizes structures (arteries, nerves, veins).

  • Transport: Blood transports nutrients, gases, and wastes.

  • Energy Storage: E.g., adipose cells store energy.

Components of Connective Tissue

• Cells:

  • Functional unit with a plasma membrane and organelles.

  • Key cell types include:

    • Adipocytes: Fat cells, store energy, provide cushioning.

    • Fibroblasts: Secrete fibers and ground substance.

    • Mast Cells: Involved in immune response, release histamine.

    • White Blood Cells (Leukocytes): Repair, fight infections.

    • Macrophages: Engulf/digest foreign materials (considered "Pacman").

• Ground Substance:

  • Fills space between cells; thicker viscous solution containing ions and proteins.

• Connective Tissue Fibers:

  • Collagen Fibers: Provide strength and rigidity; found in skin, bones, tendons.

  • Elastic Fibers: Allow stretching and recoil; found in arteries, larynx, ligaments.

  • Reticular Fibers: Form a supportive network; found in lymph nodes, spleen.

Classification of Connective Tissue

• Classified into four categories:

  1. Connective Tissue Proper

  2. Cartilage

  3. Bone

  4. Blood

Connective Tissue Proper

• Sub-categories:

  • Loose Connective Tissue: More flexible, fewer cells and fibers.

    • Areolar Tissue: Universal packing material; supports and binds other tissues.

  • Dense Connective Tissue: More cells and fibers packed closely together.

    • Dense Regular Connective Tissue: Bundles of fibers in one linear direction; found in tendons and ligaments.

    • Dense Irregular Connective Tissue: Fibers arranged in multiple directions; found in the dermis of skin, organ capsules.

    • Elastic Connective Tissue: Lowers stretch and recoil; found in the aorta, ligaments connecting spinal vertebrae.

Cartilage

• Characteristics:

  • Cells (chondrocytes) reside in lacunae, surrounded by a flexible matrix.

  • Avascular and not innervated; poor healing capacity.

• Types of Cartilage:

  • Hyaline Cartilage: Most abundant; found in rib cage, trachea, and articular surfaces of joints.

  • Fibrocartilage: Provides support and rigidity; found in intervertebral discs, pubic symphysis.

  • Elastic Cartilage: Flexible; found in ears and epiglottis.

Bone

• Characteristics:

  • Living tissue with a strong blood supply.

  • Composition: Cells (osteocytes) in lacunae and a bony matrix.

• Functions: Support and protection; e.g., rib cage, skull.

• Types of Bone:

  • Spongy Bone: Light and airy structure found at the ends of long bones.

  • Compact Bone: Dense structure around the outer portion of long bones.

Blood

• Atypical connective tissue; primarily involved in transportation rather than support.

• Composition:

  • Red blood cells (erythrocytes) carrying oxygen, leukocytes for immune functions, and platelets for clotting.

  • Cells are suspended in plasma.

Conclusion

• Summary of the connective tissue types and their functions.

• Upcoming lecture will cover muscle and nervous tissue.