Loose, Dense, Specialized
Connective Tissue Loose, Dense, Specialized Basement Membrane Collagen 68nM banding pattern and thick bundles in cross section Mesenchymal Cells Primitive cells of connective tissue Dense, Irregular Connective Tissue More Fibers than cells Irregular Connective Tissue Multiple Cells, fibers present White Adipose Development
Mesodermal or neural crest derived mesenchymal cells associated with adventitia of small venules Fibroblast-like cells determined as lipoblasts Lipoblasts deposit ECM and gather lipid, filling mature cell and compressing nucleus, cytoplasm and organelles into characteristic adipocyte shape Isolated adipocytes spherical; may appear polyhedral or ovoid in tissues, surrounded by cytoplasm and a small amt of CT Lipid is not membrane bound (unlike multilocular adipocytes, which have multiple fat-containing vacuoles) Mobilization of fat depends on neural or hormonal stimulus Triglycerides mobilized to glycerol and fatty acids; FA enter capillary for use as energy source Metabolism of Fat from Adipocytes
b Adrenergic Receptors on Fat Cells Hormone Sensitive Lipase FA + Glycerol Insulin Adapted from Horn, 2006 Adipose H & E Ultrastructure of Adipose Brown Adipose Multilocular, Thermogenic Heat Generation Uncoupled From ATP Pdtn
Nervous system stimulation Lipid mobilized, fatty acid oxidized UCP-1 moves H+ across inner mitochondrial membrane, dissipating proton gradient for ATP pdtn Energy freed as heat Cartilage Chondrocytes in an avascular extensively specialized matrix
Weight bearing, shock absorbing, porous Three kinds Hyaline, Elastic, Fibrous Differential ECM deposition aids in function Hyaline Cartilage Chondrocytes in isogenous groups
TM vs ITM reflects differential matrix distribution Ground Substance= Collagen II, PG (HA, CSulfate, KerSulfate) Proteins (eg., tenascin, FN) Highly hydrated (assists in weight bearing) Model for Indirect (Endochondral) Ossification Perichondrium = source of growth (DR connective tissue) Proliferation of chondrocytes may also be via interstitial growth Elastic Cartilage Characterized by presence of elastin fibers in hyaline ECM Flexible, non-calcifying Surrounded by perichondrium External ear, eustachian tubes, epiglottis of larynx Fibrocartilage Dense regular connective tissue + hyaline matrix
No perichondrium IG and rows of chondrocytes Fibroblast nucleii present Intervertebral disks, symphysis pubis, articular disks of mandible and sternum, meniscus of knee, places where tendon attaches to bone Resistance to shear force and compression Cartilage growth and repair
Mesenchymal cells Appositional and Interstitial growth Limited repair due to which three primary factors? Aging Limited repair, matrix calcifies, replaced by bone (how does this impact function?)