CT Classification

Question 1

What are 2 Embryonic CT?

Answer 1

1. Mesenchymal CT
2. Mucous CT

Question 2

What is Mesenchymal CT?

Answer 2

1. No fibers
2. Scattered reticular fibers
3. Form during 2nd and 3rd weeks of development
   * From Mesoderm and Neural crest cells
4. Found
   * Embryo and tooth pulp of adult
5. Few mitochondria and Little to no ER

Question 3

What is Mucous CT?

Answer 3

1. Jelly-like
2. Rich in Hyaluronic Acid
3. Found

• Umbilical cord
• WHARTON’S JELLY
• Subdermal CT of embryo

*Embyronic CT

Question 4

What is Loose (Areolar) CT?

Answer 4

1. Ground substance higher levels then collagen
2. Predominant cells

• Fibroblasts
• Macrophages

3. Vascularized

Question 5

What is Dense Irregular CT?

Answer 5

1. Collagen Type 1 fibers
2. Predominant cells
   * Fibroblasts
3. Provide resistance to stress from all directions
4. Location

• Deep dermis layer
• Capsule of organs
• Submucosa of digestive tract
• Periosteum and Perichondrium

Question 6

What is Dense Regular Collagenous CT?

Answer 6

1. Fibrocollagenous or Fibrous Tissue
2. Consist
   * Type 1 Collagen Fibers
3. Function

• Flexibility combined with great tensile strength
• Poor vascularization

4. Appear WHITE
5. Location

• Tendons
• Ligaments
• Aponeurosis
• Cornea

Question 7

What is Dense Regular Elastic CT?

Answer 7

1. Elastic fibers
   * Yellow color
2. Function

• Resist high degree of stretch
• Allows recoil of tissue

3. Location

• Large arteries (Aorta)
• Ligamenta flava
• Ligamentum Nuchae
• Suspensory Ligament of Penis

Question 8

What is Reticular CT?

Answer 8

1. Type III Collagen
2. Reticular cells
3. Form Framework of

• Lymphoid organs
• Hemopoietic organs
• Liver Sinusoids
• Pancreas
• Adrenal Glands

*Does not stain with H and E

Question 9

What is Adipose Tissue?

Answer 9

1. Grossly visible
2. Little ECM
3. Highly Vascularized
4. Body Fat

• Men: 15-20%
• Women: 20-25%

5. Store Energy as GLYCOGEN
6. Two Types

• Unilocular adipocyte (WHITE fat)
• Multilocular adipocyte (BROWN fat)

Question 10

What is Uniocular Adipocytes?

Answer 10

1. 50 to 150 µm in diameter
2. Cytoplasm
   * Displaced periphery forming thin ring
3. White adipocytes stored as Triglycerides
4. Nucleus
   * Signet Ring Appearance
5. Increase in SIZE during the first 6 months of life
6. Increase in NUMBER until 2nd year of life
7. Puberty
   * Increase in size and number of unilocular adipocytes
8. Don’t undergo Mitotic division
9. Function

• Store energy
• Thermal insulation
• Shock absorber

Question 11

What is Multiocular Adipocyte?

Answer 11

1. Brown Fat cells
2. Numberous Small Lipid Droplets
3. Cytoplasm

• Vacularized
• Numerous mitochondria

4. Function
   * Production of body heat (ONLY) by mitochondria
5. Found

• Neonates and Infants
• Between Scapulae
• Adults: Around adrenal glands