4.2 - Lab - CT Flashcards
Irregular Connective Tissue
- indicates that the extracellular fibers are oriented more or less randomly in space
- form a meshwork
Dense Regular Connective Tissue
- indicates the fibers are aligned with each other
- for the most part this is found with tendons and ligaments
Name the 3 important components to Connective Tissue
- Cells
- Extracellular Fibers
- Extracellular Ground substance
- ground substance has been washed out of soft tissues during preparation (is not good for identifying types of CT)
Compare Loose Connective Tissue with Dense Connective Tissue
Loose CT
- many more cells
- light eosinophilic stain
- collagen type I predominantly
Dense CT
- fewer cells
- much darker eosinophilic stain
- collagen type I predominantly
Papillary Dermis
= layer of looser connective tissue (in skin)
Reticular Dermis
= layer of denser connective tissue (in skin)
What is the prominent resident cell of dense irregular connective tissue
Fibroblast
Compare Dense Regular Tissue of a tendon, skeletal muscle fibers, and irregular connective tissue?
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
Unilocular adipocyte
= white fat cell
- often appear in groups (can appear alone though)
- eccentric, pancake-shaped nucleus
- second common type of resident cell
Multilocular Adipocyte
- 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
Type I collagen
- 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)
Elastic fibers are made from
elastin and fibrillin proteins
Reticular fibers are made from
type III collagen
What is a spread preparation?
a much thicker cut section of tissue
Verhoff’s Stain is used to see what kind of fiber?
- Elastic fibers
- is often deep purple in color
what is the tunica intima
- the inner layer of most arteries
- contains elastin protein in a structure called the inner elastic lamina
Compare elastin fibers to Type I collagen fibers
Elastic fibers tend to be
- less eosinophilic than type I collagen
- normally smaller and less numerous than surrounding type I collagen
Describe reticular fibers
- 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)
What is the Gomori Stained technique used for
= a silver staining technique
- used to view reticular fibers (type III collagen)
Describe type IV and VII Collagens with specific attention to their LM properties
- 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)
What is laminin?
a glycoprotein that is a major component of the lamina lucida layer of the basement membrane
