4.2 - Lab - CT

Question 1

Irregular Connective Tissue

Answer 1

• indicates that the extracellular fibers are oriented more or less randomly in space
• form a meshwork

Question 2

Dense Regular Connective Tissue

Answer 2

• indicates the fibers are aligned with each other

- for the most part this is found with tendons and ligaments

Question 3

Name the 3 important components to Connective Tissue

Answer 3

1. Cells
2. Extracellular Fibers
3. Extracellular Ground substance
   - ground substance has been washed out of soft tissues during preparation (is not good for identifying types of CT)

Question 4

Compare Loose Connective Tissue with Dense Connective Tissue

Answer 4

Loose CT

• many more cells
• light eosinophilic stain
• collagen type I predominantly

Dense CT

• fewer cells
• much darker eosinophilic stain
• collagen type I predominantly

Question 5

Papillary Dermis

Answer 5

= layer of looser connective tissue (in skin)

Question 6

Reticular Dermis

Answer 6

= layer of denser connective tissue (in skin)

Question 7

What is the prominent resident cell of dense irregular connective tissue

Answer 7

Fibroblast

Question 8

Compare Dense Regular Tissue of a tendon, skeletal muscle fibers, and irregular connective tissue?

Answer 8

Dense Regular

• the most eosinophilic
• ordered + tightly packed collagen Type I
• scattered fibroblast

Skeletal Muscle

• tightly packed but less eosinophilic
• striations

Irregular
- Looser packed or more randomly organized

Question 9

Unilocular adipocyte

Answer 9

= white fat cell

• often appear in groups (can appear alone though)
• eccentric, pancake-shaped nucleus
• second common type of resident cell

Question 10

Multilocular Adipocyte

Answer 10

• very rare cell
• lipid is in multiple droplets (as to opposed to one lg. singular one)
• relatively more abundant in infants and small animals
• main FXN = produce heat from fat
• cytoplasm is more abundant and eosinophilic (due to lg. # of mitochondria)
• nucleus is more ovoid + centrally located
• dense network of capillaries is often seen amongst multilocular adipocytes

Question 11

Type I collagen

Answer 11

• primary fibrous component of most loose and dense connective tissue
• when type I collagen in CT is not the majority or the only largely expressed fiberous component - it is an indication of a change in the mechanical properties of the tissue (i.e. if more elastin is present)

Question 12

Elastic fibers are made from

Answer 12

elastin and fibrillin proteins

Question 13

Reticular fibers are made from

Answer 13

type III collagen

Question 14

What is a spread preparation?

Answer 14

a much thicker cut section of tissue

Question 15

Verhoff’s Stain is used to see what kind of fiber?

Answer 15

• Elastic fibers

- is often deep purple in color

Question 16

what is the tunica intima

Answer 16

• the inner layer of most arteries

- contains elastin protein in a structure called the inner elastic lamina

Question 17

Compare elastin fibers to Type I collagen fibers

Answer 17

Elastic fibers tend to be

• less eosinophilic than type I collagen
• normally smaller and less numerous than surrounding type I collagen

Question 18

Describe reticular fibers

Answer 18

• made from type III collagen
• may occur with or without surrounding type I collagen
• serve as scaffolding of organs composed chiefly of migratory cells (i.e. lymph nodes/spleen)
• also found where CT support should be minimized (liver, lung)
• very fine + delicate fibers
• usually arranged in net-like lattice
• Main fiber type in mesenchymal tissue
• best demonstrated with Silver stain techniques - i.e. Gomori Technique (silver appears deep black)

Question 19

What is the Gomori Stained technique used for

Answer 19

= a silver staining technique

- used to view reticular fibers (type III collagen)

Question 20

Describe type IV and VII Collagens with specific attention to their LM properties

Answer 20

• Smallest fibrils of all the collagens we are considering
• most commonly found in basement membrane as part of lamina densa layer
• ARE NOT VISIBLE IN LM individually (only as part of the basement membrane staining - as in PAS stain)

Question 21

What is laminin?

Answer 21

a glycoprotein that is a major component of the lamina lucida layer of the basement membrane