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