connective tissue Flashcards
what is the function of connective tissue
- forms supporting framework fro body
- binds together body cells and tissue
what is connective tissue composed of
- living cells
- ecm
there are different forms of connective tissue with different physical properties
what are three way connective tissue is categorised as
- loose
- dense
- specialised
where is loose connective tissue found and what is its role
- found throughout the body
- composed of fine fibres of collagen and elastin is embedded in a ground substance
- it is a soft tissue used for spacing and packing
- it also connects the muscle layer and skin an eg. adipose tissue - contain fat cells
what is the major cell found in connective tissue
- fibroblasts
structure of dense connective tissue
- contain large collagen fibres which provide strength to the tissue
- as there are lots of collagen fibres it means there is very little ground substance
- due to the compact arrangement of collagen fibres resists stretching
- dense connective tissue comprises of ligaments and joints which connect bone to bone
structure and function of specialised connective tissue
- have a very specialised function which has a direct result on structure and function of ecm
- examples inc. bone, enamel, dentine
what are the 2 groups of cells in connective tissue and their roles
- structural cells
for synthesis and maintenance of structural components - defence cells
for non specific defence reactions
what are 4 examples of structural cells (make ecm)
- fibroblasts
- adipocytes (fat cells)
- bone cells (osteocytes)
- chondrocytes (cartilage cells)
fibroblasts
- make collage and other ecm components and maintain it
adipocytes
- have protective and thermoregulatory functions
- storage of fats
- insulation/ protection
- supporting tissue eg. beneath the skin providing smooth body outline
what are mesenchymal cells (MSCs)
- they are indistinguishable from fibroblasts
- can differentiate into new connective tissue
- present in small numbers
what are two type of defence cells and their role
- macrophages
motile cells that engulf foreign materials eg bacteria. - neutrophils or lymphocytes
present during inflammatory reactions
2 main components ecm made up of
- fibres
- ground substance (semi solid gel)
what are the two main fibres found in ecm
- collagen fibres
high tensile strength, made of protein collagen - elastin fibres
low tensile strength, high elasticity
what is ground substance made from
- semi solid gel
- made of protein and fluid
- many em proteins are a complex nature of long chain molecules with side chains
3 examples of proteins with side chains
- proteoglycans - carbohydrate side chain - hydrophilic
- glycoproteins - protein core with sugar side chain
- long carbohydrate chain - no protein core, long chains of glycosaminoglycans (GAG)
the specialised nature of ecm components
- give specific mechanical properties eg cartilage
main feature of cartilage
- it is avascular
what are 4 types of cartilage
- hyaline cartilage
- fibrocartilage
- elastic cartilage
- hypertrophic cartilage
what type of collagen fibres are hyaline cartilage made from
- hyaline cartilage characterised by dense ecm rich in collage type 11 fibres and ground substance
what cells are embedded in the ecm as a sparse amount
- chondrocytes
- responsible for maintaining the ecm
where is hyaline cartilage found
- covers the surface of bones in synovial joint = articular cartilage
- hyaline cartilage is main component of nasal septum and c shaped rings found in trachea - prevents wall of trachea collapsing
what are the function of articular cartilage
- provide a smooth, near frictionless surface to enable gliding motion and being a shock absorbed to protect the bones from forces generated when eg walking
what is fibrocartilage made of
- dense orderly arrangement of thick interlaced collagen type 1 fibres
- very little ground substance compared to hyaline cartilage
- found in the intervertebral discs
- fibrocartilage also comprises the articular disc found in the tmj
elastic cartilage
- properties of elasticity
- ground substance and collagen fibres
- contains a network fo fibres of elastin which enable elastic cartilage to have a rigid but elastic framework
- main function to provide and maintain shape when tissue is twisted
hypertrophic cartilage
- it is an essential intermediate tissue in bone formation
four functions of bone
- provide support for body
- protection of internal organs
- protects bone marrow
- mineral store
two types of bone
- cortical/compact
dense, v strong, forms the outer layer of all bone - trabecular/cancellous
weak, porous meshwork
