connective tissue Flashcards
what are the functions of connective tissue?
-mechanical support
-protection and insulation
-compartmentalisation
-metabolic support
what dopes the function of connective tissue depend on?
-matrix constituents
-proportions of matrix components
-organisation
-ability to interact
what are the two types of connective tissue?
-areolar connective tissue
-fibrous/ dense connective tissue
what does areolar connective tissue do? what does it consist of?
holds organs and epithelia in place and consists of a variety of loose proteinaceous fibres including collagen and elastin
what does fibrous connective tissue consist of and what does it do?
consists of densely packed collagen fibres with great tensile strength and forms dermis ligaments and tendons
whats the connective tissue in blood?
a fluid matrix around cells
what’s the connective tissue in adipose?
mainly cells surrounded by thin matrices
what is the connective tissue in bone?
its a rigid matrix of collagen fibres embedded in a mineralised matrix with hydroxyapatite
what is the connective tissue in cartilage?
a matrix of polysaccharides with a few collagen II fibres
what two types of cells do connective tissues contain?
either resident cells or transient cells
what do fibroblasts do and give examples
responsible for secretion and maintenance of the matrix within connective cell tissue e.g.
-fibroblasts becoming myofibroblasts at the site of an open wound
-osteocytes to osteoclasts and osteoblasts in the bone
-chondrocytes to chondroblasts in the cartilage
what are the components of extracellular matrix?
-collagen
-elastin
-proteoglycans
-glycoproteins
what percentage of protein in the body is collagen?
25-30%
what type of collagen does do basement membranes contain?
type IV and type VIIII
what do basement membranes surround?
-muscle and fat cells
-underlie epithelial cells
-underlie endothelial cells
what collagen are in facits?
type IX and type XII
what are the different collagen orientations giving examples
-one direction in the force of extertion e.g. optic nerve
-basket like weave criss-crossed to withstand tension e.g. lamina cribrosa
-regular erray of small uniform diameter fibrils e.g. cornea
how are the collagen fibrils in the cornea transparent?
by being within lamellae to allow light to be transmitted
give two elastic fibres
elastin core
fibrillin microfibrils
what is the role of elastic fibres?
-elasticity
-extensibility
what are the roles of fibrilin in the lens?
to form suspensory fibres that make up the zonules that secure the lens
how is both elastin and collagen useful in the tissue?
elastin allows deformation and recovery of the structure
collagen provides strength and limits deformation to prevent damage
name a protein in the extracellular matrix. what does it contain? name some types of this chemical
proteogylcan which contains glycosaminoglycans (GAGs) some of which are chondroitin sulphate, heparan sulphate, dermatan sulphate and keratan sulphate
what do proteoglycans have high sulphation?
so they have a negative charge. this makes them hydrophillic and allows them to form a hydrated gel which can withstand compression
what are the three functions of proteoglycans?
-regulation of collagen fibril diameter,
-biomechanical function where they resist compression
-cell signalling
give examples of glycoproteins
-fibronectin
-laminin
-vitronectin
-tenascin
-thrombospondin
what are the functions of glycoproteins?
-cell-matrix attachment
-cell adhesion
-regulation of cell migration, cell attachment, matrix organisation, shape
what is the function of glycosaminoglycans in connective tissue?
to give ability to resist compression
