4. Connective Tissue Cells: General & Fibroblasts

resident cells

(fixed) undergo mitosis and spend most of life in CT

four types of fibroblasts

active, inactive, myofibroblasts, mesenchymal cells

fibroblast location

close to collagen fibers

myofibroblast smooth muscle similarities

contain bundles of actin filaments and dense bodies (but no external lamina)

inactive fibroblast nucleus

dark, elongated, heterochromatic

inactive fibroblast presence

dense, not growing, connective tissue

fibroblast appearance

diff in diff tissue types

mesenchymal cells presence

embryonic connective tissue

myofibroblast properties

fibroblasts and smooth muscle

types of resident cells

fibroblasts, adipocytes, macrophages, mast cells

inactive fibroblasts

fibrocytes

inactive fibroblast structure

limited cytoplasm, less well-developed Golgi and RER

active fibroblasts presence

loose connective tissue, actively growing tissue, wound repair

active fibroblast nucleus

pale, oval, euchromatic with one or more nucleoli

mesenchymal cells unique feature

pluripotent, give rise to other connective tissue cells

fibroblast cell

principal resident cell of CT

fibroblast function

producing ECM components (collagen & elastic fibers, GAGs, proteoglycans, multiadhesive glcoproteins)

mesenchymal cells appearance

resembles active fibroblast (pale, euchromatic nuclei, well-developed RER and Golgi)

two types of connective tissue cells

resident and transient

active fibroblast structure

thin processes, abundant cytoplasm, RER and Golgi

myofibroblast presence/use

wound sites, wound closure