Transcript ctcells

Class:
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Cells of Connective Tissue Proper:
•Fixed cells and transient cells
•Classification of Connective Tissue “Proper”
•- Loose (aerolar) CT
•- dense CT
•Reticular tissue
•Adipose tissue
Fixed Connective Tissue Cells:
•Fibroblasts, active and inactive
•Myofibroblasts
•Pericytes
•Adipose Cells
•Mast Cells
•Macrophages
Fibroblasts:
Synthesize the ECM
Fibroblasts change from inactive to active state.
Active Fibroblasts:
-secrete ECM, wound healing
-beside collagen bundles
-elongate and fusiform
-in H & E sections, seem to blend in with ECM
-Nucleus is large, ovoid, granular, prominent nucleolus
-TEM shows signs of protein synthesis and secretion
-contain actin and myosin
Inactive Fibroblasts:
-smaller than Active Fibroblasts
-nucleus smaller and rounder
-TEM, ribosomes are free
-capable of some movement
-can divide during wound healing
-can differentiate into adipose cells, chondrocytes,
osteoblasts
Myofibroblasts
-modified fibroblasts
-hard to distinguish from fibroblasts
-have cytoplasm like smooth muscle cells
-abundant during wound healing
Pericytes
-small, perivascular cells
-located around capillaries and venules
-may differentiate into endothelial or smooth muscle cells
Adipose Cells
-don’t proliferate
-differentiate from undifferentiated mesenchymal cells
and maybe from fibroblasts (application to obesity
studies)
-white adipose tissue is unilocular
-brown adipose tissue is multilocular
Mast Cells:
-large, 20 to 30 mm diameter
-ovoid cells with central, round nucleus
-contains lots of granules
-granules contain
-heparin, a sulfated glycosaminoglycan
-histamine
-other molecules for inflammatory responses
Macrophages:
-some are fixed and some are transient
-phagocytes
-irregular shape
-10 - 30 mm diameter
-cytoplasm is basophilic
-fn: phagocytize dead or damaged cells, debris and
digest this material
Transient Connective Tissue Cells
Plasma cells and Leukocytes
Leukocytes move from the blood
-same cells are in the blood
-Neutrophils phagocytose and digest bacteria
-Eosinophils release cytotoxins agains bacteria
-Lymphocytes are important for immune responses
Plasma Cells
-differentiate from lymphocytes
-large, ovoid (20 mm diameter)
-located at inflamed and infected sites
-round nucleus with “clockface chromatin”
-produce antibodies