Connective Tissue Cells
Connective tissue cells are responsible for the synthesis and maintenance of the extracellular matrix (ECM) and play a vital role in immune responses and tissue repair.
Origin
Connective tissues originate from embryonic mesenchyme.
Mesenchyme: an embryonic tissue composed of undifferentiated mesenchymal cells embedded in a viscous ground substance.
Mesenchymal cells can differentiate into various connective tissue cell types, including fibroblasts, adipocytes, chondroblasts, and osteoblasts.
Resident Cells
Fibroblasts: These are the most common cells in connective tissue proper.
They synthesise and secrete the components of the ECM, including collagen, elastin, GAGs, proteoglycans, and multiadhesive glycoproteins.
They are targets of growth factors that influence cell growth and differentiation.
Active fibroblasts:
Have abundant rough endoplasmic reticulum and a large, euchromatic nucleus
Indicative of their role in protein synthesis.
Inactive fibroblasts (or fibrocytes):
Become more spindle-shaped.
Are less active in ECM production.
Myofibroblasts:
A type of fibroblast involved in wound healing
Possess contractile functions similar to smooth muscle cells.
Adipocytes (fat cells):
Specialise in storing lipids, primarily as triglycerides.
Play a crucial role in energy storage, insulation, and cushioning of organs.