histology of cartilage Flashcards
what are the two types of connective tissue
irregular and regular
what are the types of irregular connective tissue
loose/areolar, dense irregular, adipose tissue
desrcibe loose/ areolar connective tissue and some examples please
lamina propria, submucosa of the GI. this has fibres arranged in a meshwork that will facilitate movement allowing fibres to easily slide past one another
describe dense irregular connective tissue
dermis, adventitia and capsules of large blood vessels. these fibres are more pattern like and are arranged in a manner to support mechanical stresses
describe regular connective tissue and give examples
regular fibres arranged in manners that are in line with the stress they face, fascia, ligaments and tendons
what two things broadly make up connective tissue
cells plus ECM
what makes ECM
fibres plus ground substance
resident cells of connective tissue have what origin
mesenchymal origin
describe fibroblasts - like their function and appearance and that
spindle shaped resident cell, they adhere to fibres, produce ECM. large euchromatic nuclei with prominent nucleosomes and abundance of rER and mitochondria.
whats the process of making collagen fibres
collagen starts as an alpha helix, three alpha helices come together to make procollagen. collagenase cleaves uneven ends from procollagen to make tropocollagen. many tropocollagen plus binding protein makes collagen fibrils. fibrils come together to form collagen fibres
whats elastin made of
elastin is single standed elastin fibres linked by cross linking proteins.
whats the process of making ground substance
GAGs plus a core protein binds to make a proteoglycan monomer. the proteoglycan monomers adhere to hyaluronan via link proteins to make proteoglycan polymers
the negative charge of GAGs means what
means that the GAGs in the proteoglycan monomers repel one another - so compressive resistant. also they attract water to aid the compression resistance
what are the three types of cartilage
hyaline, white fibrous and yellow elastic
describe the chondroblasts, their role, location
these are mesenchymal cells which synthesise ECM. they are found as groups of 4 ish cells in a chondron, with each cell in the chondron being housed in a lacunae
describe chondrocytes, their role and location
these maintain the matrix of the cartilage. they have large euchromatic nuclei with prominent nucleoli. have rER golgi and mitochondria in abundance. they secrete ECM, fibres and ground substance to a lesser extent than the chondroblasts.
describe hyaline cartilage
opalescent appearance. chondrocytes are rounded and arranged in the chondrons. matrix is homogenous with lots of ground substance. has no visiblefibres and is rich in proteoglycans - hence quite water retentative so its smooth
describe the intermediate zone
chondrocytes are larger and more round collagen is oblique
describe the superficial zone
cells are small, elongated and run parallel to the surface. collagen is parallel with the articular surface allowing for the smooth articulation of bone at the surface
describe articular cartilage
is a type of hyaline cartilage but it has no perichondrium. thickness of this type does not increase with load. it forms a smooth but deformable layer that increases the bony congruency of joints. has 3 different cell arrangements - superficial zone, intermediate zone, radial zone
describe the radial zone
this has vertically arranged collagen allowing for weight bearing function and compression under weight
describe white fibrocartilage
dense, white and fibrous texture. load bearing function so it resists high compressive forces. rows of chondrocytes housed in lacuna are lined between collagen. we also have fibroblasts in this collagen this produces proteoglycans and collagen but also act as stem cells
describe yellow elastic collagen
fine yellow elastic fibres, cells are single or in groups. collagen and elastin also found arranged in groups.
