CT ECM

Question 1

What is ECM?

Answer 1

1. Composed

• Ground substance (produced by Fibroblasts)
• Fibers
  
  • Collagen
  • Reticular
  • Elastic
• Tissue Fluids

Question 2

What is Ground Substances in ECM?

Answer 2

1. Contain

• Glycosaminoglycans (GAGs)
• Proteoglycans (PG)
• Adhesive glycoproteins
• Proteolytic Enzymes
  
  • Degradation

Question 3

What is Glycosaminoglycans (GAGs)?

Answer 3

1. Part of Ground Substances
2. Formerly called MUCOPOLYSACCHARIDES
3. Long-chained polysacchrides
4. Sugar used
   * HEXOSAMINE (glycosamine)
5. Types

• Sulfated GAGs (synthesized in rER and Golgi)
  
  • Heparan sulfate
  • Dermatan sulfate
  • Keratan sulfate
  • Chondroitin 4-sulfate
  • Chondroitin 6-sulfate
• Non-Sulfated GAGs
  
  • Hyaluronic Acid
    
    • No protein core

6. Negatively charged

• Osmotically attract water to ECM
• Attracts Na⁺ ions

Question 4

What is Proteoglycans?

Answer 4

1. Proteins modified by Glycosaminoglycan (GAG)
2. Core Protein present
3. Resist Compression

Question 5

What is Hurler Disease?

Answer 5

1. Mucopolysaccharidosis type 1, MPS 1
2. Lysosomal storage disease
3. Altered Ground Substance

Question 6

What is Deficiency of L-iduronidase?

Answer 6

1. Stop degradation of Heparan and Dermatan Sulfate

* Ground Substance related

Question 7

What is Staphylococcus aureus infection?

Answer 7

1. Hyaluronidase
2. Cleaves Hyaluronic acid
   * Rapid spread of bacteria into tissue

Question 8

What is Osteoarthritis?

Answer 8

1. Degradation of Proteoglycan
   * Aggrecan
2. Cartilage breakdown (erosion)

Question 9

What are Glycoproteins?

Answer 9

1. Contain protein moiety attached to carbohydrates
2. Hold tissue structures together
3. Ex

• Fibronectin
  
  • Binding site for ECM and Integrin
• Laminin
  
  • Binds basal lamina to epithelial cells

4. Others

• Osteonectin
  
  • Binds Ca hydroxyapatite to collagen I
• Chondronectin
  
  • Binding sites for Collagen II
• Entactin
  
  • Component of basement membrane
• Tenascin
  
  • In embryonic tissue
  • For cell migration

Question 10

What are Integrins?

Answer 10

1. Linker proteins that bind to

• Collagen
• Fibronectin
• Laminin

2. Role

• Cell adhesion
• Cell movement and migration
• Wound Healing

Question 11

What is Collagen 1?

Answer 11

1. Synthesizing Cells

• Fibroblast
• Osteoblast
• Odontoblast
• Cementoblast

2. Function
   * Resist Tension
3. Location

• Dermis
• Tendon
• Ligaments
• Bone
• Dentin
• cementum

Question 12

What is Collagen 2?

Answer 12

1. Synthesizing Cells
   * Chondroblasts
2. Function
   * Resists Pressure
3. Location

• Hyaline cartilage
• Elastic cartilage

Question 13

What is Collagen 3?

Answer 13

1. Synthesizing Cells

• Fibroblast
• Reticular cells
• Smooth muscle cells
• Hepatocyte

2. Function

• Structural framework of
  
  • Spleen
  • Liver
  • Lymph nodes
  • Smooth muscle
  • Adipose tissue

3. Location

• Lymphatic system
• Spleen
• Liver
• Cardiovascular system
• Lungs
• Skin

Question 14

What is Collagen IV?

Answer 14

1. Synthesizing Cells

• Epithelial cells
• Muscle cells
• Schwann cells

2. Function

• Forms meshwork of Lamina Densa of Basal Lamina
• Provide support and filtration

3. Location
   * Basal Lamina

Question 15

What is Collagen V?

Answer 15

1. Synthesizing cells

• Fibroblast
• Mesenchymal cells

2. Function
   * Associated with Type I collagen and placental ground substance
3. Location

• Dermis
• Tendon
• Ligaments
• Placenta

Question 16

What is Collagen VII?

Answer 16

1. Synthesizing cells
   * Epidermal cells
2. Function
   * Forms anchoring fibrils
3. Location
   * Junction of epidermis and dermis

Question 17

What are Reticular Fibers?

Answer 17

1. Type III collagen fibrils
2. Prominent in Loose CT
3. Found
   * Lamina reticularis (basement membrane)
4. Role

• Endocrine glands
• Liver
• Hemopoietic tissue
• Lymphoid organs
• Thymus

5. Does NOT stain with H&E
   * Stain with SILVER SALTS and PERIODIC ACID-SCHIFF (PAS)

Question 18

What are Elastic Fibers?

Answer 18

1. Do not form Banding Pattern
2. Composed

• Elastin protein
• Fibrillin microfibrils

3. Rich in GLYCINE, PROLINE, and LYSINE
4. Stain

• Yellowish color in gross tissue
• Do NOT stain with H&E
• Dye: ORCEIN (BLACK)

Question 19

What is Intestitital Pulmonary Fibrosis?

Answer 19

1. Overproduction of Fibroblasts
2. Swelling and scarring of alveoli
3. First appears during exercise

• Dry cough
• Clubbing (Enlarged fingertips)

Question 20

What is Keloid?

Answer 20

1. Excessive accumulation of collagen during wound healing

Question 21

What is Ehlers-Danlos Syndrome?

Answer 21

1. Abnormal synthesis and cross linking of TROPOCOLLAGEN
2. Hyperextensive skin
3. Severe Bruising
4. Common condition in Contortionists

Question 22

What is Chondrodysplasias?

Answer 22

1. Mutation in Type 2 collagen
2. Bone and Joint deformities

Question 23

What is Osteogenesis Imperfecta?

Answer 23

1. “Brittle Bones”
2. Mutation in Type 1 Collagen
   * Failure to assemble triple helix
3. “Child Abuse” mistaken
4. Characteristics

• Multiple bone fractures
• Defective teeth
• Deafness
• Heart Valve disorder
• Blue Sclera

*Type 2 OI = Death

*Type 3 OI = Severe and progressive

Question 24

What is Scurvy?

Answer 24

1. Vitamin C deficiency
2. Defective HYDROXYLATION OF PROLINE
3. Unstable alpha chain helices
4. Characteristics

• Bleeding gums
• Edema
• Hemorrhage of mucous membrane
• Failure of wound healing

Question 25

What is Marfan Syndrome?

Answer 25

1. Defect in Fibrillin-1 protein 2. Defective elastic fivers 3. Characteristics * Tall * Long limbs * Long thin fingers * Dislocation of lens * HEART defects (mitral valve prolapse) * Spontaneous pneumothorax * Pectus excavatum