Connective Tissue

Question 1

Fibroblast

Answer 1

-Most abundant connective tissue cell
-Derives from mesenchymal cells
-Active fibroblast are elongated, fusiform; typically only their nuclei are visible in H&E sections
-Large elongated nucleus with prominent nucleolus
-Abundant RER, Golgi
-Inactive fibroblasts (called fibrocytes) are smaller, with less evidence of protein machinery

Question 2

Myofibroblasts

Answer 2

-Intermediate between fibroblasts and smooth muscle cells
-Possess bundles of actin and myosin like smooth muscle cells, but shape is similar to fibroblast
-Abundant in areas of would healing
-Found in periodontal ligament (involved with tooth eruption)

Question 3

Pericytes

Answer 3

-Derived from mesenchymal cells
-Partially surround endothelial cells of capillaries and small venules
-Multipotential/pluripotential (Can differentiate into other cell types such as vascular smooth muscle cells, fibroblasts, adipocytes (neural cells, glial cells, skeletal muscle fibers)
-Thought to modulate function of endothelial cells; have contractile properties to facilitate blood flow
-Surrounded by basal lamina (separate from connective tissue compartment)
-Intermediate between endothelial cells and smooth muscle cells

Question 4

Adipose cells

Answer 4

-Derived from mesenchymal cells
-Post-mitotic, terminally differentiated
-Functions include synthesis and storage of triglycerides and production of estrogen and leptin