Connective Tissue

Question 1

Fibroblasts

Answer 1

• Spindle-shaped, elongated
• Prominent nucleolus
• Most DNA is uncoiled (NOT DENSE) b/c making a lot of diverse products
• H&E stain- looked just like a nucleus b/c both cytoplasm and extracellular matrix stain red so blend together
• Function- make ECM components (fibers); also make MMPs

Question 2

Macrophages

Answer 2

• Irregular oval shape, highly folded surface, euchromatic nucleus and heterogeneous vesicles
• Function- phagocytose aged ECM components, infectious microorganisms, MHC II presenter
• Derived from bone marrow stem cells

Question 3

Plasma Cells

Answer 3

• “Clockface” chromatin - clumps of heterochromatin on edge of nucleus and a distinct nucleolus
• Lots of rough of ER b/c making proteins
• Proteins immediately released so NO vesicles
• Bluer than most cytoplasm b/c RNA
• Function- makes 1 product - specific antibody

Question 4

Mast Cells

Answer 4

• Hallmark- uniform secretory granules (densely-stained, homogenous, all stain red)
• Activation-
  
  • Exposed to antigen first time
  • Immediately bind antigen next time

Question 5

Adipocytes (2 types)

Answer 5

• White fat- large, round cell w/ 1 large vacuole; laterally displaced nucleus (small nucleus on edge while rest of cell is open/white)
  
  • Special stains - Sudan IV (red) and osmium tetraoxide (black)
  • Function- storage and metabolism of energy AND secretion of adipokines (leptin, adiponectin, TNFalpha, inflammatory mediators)
• Brown fat- must lipid droplets and must mitochondria; nucleus not pushed to side
  
  • Function- contains thermogenin which uncouples ETC —> less ATP and more heat production

Question 6

Lymphocytes

Answer 6

• Small; prominent, dense heterochromatin
• T and B lymphocytes
• Appear as little purple dots

Question 7

Neutrophils

Eosinophils

Basophils

Answer 7

• Neutrophils- stain a neutral pink
• Eosinophils - stain red
• Basophil- stain blue

Question 8

Connective Tissue Classification (3 Major Types)

Answer 8

• Loose Irreg (Areolar)
  
  • Support for blood vessels, nerves, glands, mesenteries, hypodermics and lamina of propria of tubular organs
  • Copious gelatinous ground substance allows for permeation of O2 and CO2
  • Site of inflammation
  • Limited amount of fibers
• Dense Irreg
  
  • Withstand stretch in all directions
  • Deep layer of dermis, fibrous capsules, trabecular of glands, fibrous wrappings of heart, bones, muscles, and valves of heart
• Dense Reg
  
  • Tendons - transmit full force of muscle to bone (no stretching)
    
    • 2 connective tissue sheaths w/ synovial fluid between
  • Ligaments- hold bones together at joints
    
    • Web-like structure for strength at articulating joints
  • Corneal Stroma

Question 9

MMPs

Answer 9

enzymes to degrade ECM (collagenase, elastase, gelatinase, etc)

Made by fibroblasts

Inhibited by TIMPs

Require zinc co-factor (why you use zinc cough drops)

“Matrix Metalloproteinases”