5.4

Question 1

How are connective tissue and epithelial tissue similar? How are they different?

Answer 1

Similarities – Both form membranes, lining cavities and surfaces.

Differences –
o Epithelial – Mostly cells, avascular, forms protective barriers.
o Connective – Mostly extracellular matrix, vascularized, provides support.

Question 2

What are the three basic constituents of connective tissue?

Answer 2

Extracellular fibers, ground substance, and cells

Question 3

List seven functions of connective tissue

Answer 3

1. Forms metabolic and structural connections between other tissues.
2. Forms a protective sheath around organs.
3. Helps insulate the body.
4. Acts as a reserve for energy.
5. Provides the frame that supports the body.
6. Composes the medium that transports substances from one region of the body to another.
7. Plays a vital role in the healing process and in the control of invading
   microorganisms.

Question 4

Compare and contrast collagenous, reticular, and elastic fibers

Answer 4

• Collagenous fibers – Thick, strong, and provide tensile strength (e.g., tendons, ligaments).
• Reticular fibers – Thin, branched, form a supportive network (e.g., lymph nodes, spleen, liver).
• Elastic fibers – Stretchy, coiled, allow flexibility (e.g., skin, lungs, blood vessel
  walls).

Question 5

What are GAGs and what role do they play in connective tissue? Why do you suppose animals with joint injuries are sometimes given dietary supplements of GAGs?

Answer 5

• What They Are: Long, unbranched polysaccharide chains that form a key component of the ground substance in connective tissue.
• Role in Connective Tissue: Organize and orient the formation of collagen fibers, Bind water to help maintain hydration, providing cushioning and resilience to tissues. Contribute to the viscosity and elasticity of the extracellular matrix, which is especially important in joints.
• Why They’re Supplemented for Joint Injuries:
  Joints, particularly the cartilage, rely on GAGs like hyaluronic acid (the most common GAG) for lubrication and shock absorption.
  Dietary supplements of GAGs may help improve joint healing and function by supporting the repair of cartilage and reducing friction and inflammation.

Question 6

Can you give three examples of cells that are transient in connective tissue? Can you describe their form and function?

Answer 6

• Leukocytes – Large, round immune cells that move through blood vessel
  walls (diapedesis) to fight infections.
• Mast Cells – Oval-shaped with granules containing histamine and heparin,
  triggering inflammation.
• Macrophages – Large, irregularly shaped cells that engulf microbes, dead
  cells, and debris for immune defense

Question 7

What are fibroblasts and what role do hey play in connective tissue?

Answer 7

Fibroblasts are fixed cells. They are large, irregularly shaped cells that
manufacture and secrete both the fibers and the ground substance
characteristic of their particular matrix. As the cells mature and the matrix is
formed, fibroblasts adopt a less active role. If additional matrix is required later, the cells can convert back to the active form.