Histology Connective Tissue Quiz

Overview of Connective Tissue

• Provides a matrix for support and connection of other tissues while facilitating metabolite diffusion.
• Primarily composed of extracellular material, rather than cells, forming supportive stroma within organs.

Origin of Connective Tissue

• All adult connective tissues derive from mesenchyme, an embryonic connective tissue with undifferentiated cells in a gel-like matrix.
• Originates from mesoderm.

Characteristics of Connective Tissue

• Abundant throughout the body with a diverse range of functions and structures.
• Composed of various cells and extracellular matrix, allowing for varied roles.

Functions of Connective Tissue

• Encloses and separates organs through capsules.
• Connects tissues with tendons and ligaments.
• Supports movement via bones.
• Stores fat and provides cushioning and insulation.
• Transports nutrients and waste through blood.
• Protects the body with immune system cells.

Types of Connective Tissue Cells

• Resident Cells: Include fibroblasts, myofibroblasts, macrophages, adipocytes, mast cells, lymphocytes, and plasma cells.
• Wandering Cells: Include neutrophils, eosinophils, basophils, and monocytes.

Connective Tissue Cell Functions

• Fibroblasts: Major cells synthesizing collagen, reticular, and elastic fibers, along with ground substance components.
• Fibrocytes: Inactive or resting cells, smaller than fibroblasts.
• Adipose Cells: Store fat primarily as triglycerides; predominant in adipose tissue.
• Macrophages: Engulf debris and pathogens; important for immune response and derived from blood monocytes.
• Lymphocytes and Plasma Cells: Produce antibodies and are key in immune defense.
• Mast Cells: Release histamine in response to allergens, triggering allergic reactions.

Connective Tissue Fibers

• Collagen Fibers: Most prevalent protein in the body, providing strength.
• Reticular Fibers: Form delicate networks and are mainly composed of type III collagen.
• Elastic Fibers: Allow stretching; composed of elastin and found in areas requiring elasticity, such as blood vessels.

Extracellular Matrix Components

• Composed of protein fibers (collagen, reticular, elastic) and ground substance (GAGs, proteoglycans).
• Tissue fluid supports metabolic functions, allowing nutrient and waste diffusion.

Categories of Connective Tissue

• Embryonic Connective Tissue: Includes mesenchyme and mucoid tissue (found in the umbilical cord).
• Adult Connective Tissue:
  • Connective Tissue Proper:
    • Loose (areolar) tissue with irregular cell and fiber arrangement.
    • Dense connective tissue with packed fibers (regular and irregular types) for strength and resistance.
  • Specialized Connective Tissue: Includes adipose tissue, elastic tissue, cartilage, bone, and blood.

Additional Types of Connective Tissue

• Dense Regular Connective Tissue: Organized fibers provide high tensile strength (e.g., tendons and ligaments).
• Dense Irregular Connective Tissue: Randomly oriented fibers for multi-directional strength; found in skin and joint capsules.
• Reticular Tissue: Forms a 3D network supporting cells in lymphoid organs, allowing immune cell access and monitoring.

Ground Substance

• Composed of GAGs (hyaluronic acid), proteoglycans, and glycoproteins; acts as a lubricant and protective barrier.
• Binds with water, helping to regulate fibroblast proliferation and allowing temporary cell attachment.

Tissue Fluid

• Similar to blood plasma; facilitates nutrient and waste diffusion in connective tissue.
• Governed by hydrostatic pressure and colloid osmotic pressure, maintaining fluid balance in capillaries.