HUBS 191 Lecture 5 Flashcards
how does bone growth start
with a cartilage model which forms 6 weeks after fertilisation and acts as a blueprint for the structure of bones
what is the process of turning cartilage into bone called
endochondral ossification
where are the primary and secondary ossification centres
primary - diaphysis
secondary - epiphyses
what is the cartilage between the diaphysis and epiphyses that allows for growth of the bone (in length) called
the growth (epiphyseal) plates
what is appositional growth
growth in the width of bones in order to support our body weight as we get older
what is a joint
a combination of soft tissues that hold together bones (this involves the ends of bones).
what are the three types of cartilage
elastic (not important for hubs)
hyaline/articular cartilage
fibrocartilage
what tissue composes ligaments, tendons and joint capsules
DFCT - dense fibrous connective tissue
what do chondrocytes do
make cartilage in lacunae
what are the positives and negatives of cartilage being avascular
if force is applied it has no effect on the cartilage because there is no blood flow to stop
its very hard to get nutrients in to the cells that need them
how does the cartilage diffuse nutrients into the chondrocytes
the cartilage joint loads which means it pushes fluid (containing nutrients) into the tissue and hopes that the cells get the nutrients they need
what makes hyaline cartilage good at resisting compression
it has a high water concentration in the matrix
what is the function of hyaline cartilage
to resist compression. it moulds to the bone surface where the bones articulate and provides a smooth frictionless surface for movement
what is the function of fibrocartilage
to resist compression and tension (its a good shock absorber, can distribute weight force over a wider area and can be used to deepen articulations)
what is fibrocartilage composed of
lots of collagen fibres in bundles that are aligned with the stresses/tensions that the cartilage will experience. there are also chondrocytes in lacunae. the ECM also contains some water
what is DFCT composed of
fibroblasts (cells that make fibre, usually collagen), collagen fibres and some elastin fibres (not always)
What is the function of DFCT
to resist tension - there is no room in the ECM for water so it can’t resist compression very well
why is DFCT slow to heal
because it is so tightly packed and has very little vascularity which means it takes a long time for nutrients to get through
what is the function of ligaments
to connect bone to bone
what are ligaments composed of
collagen and elastin (which allow them to resist tension)
what is the function of tendons
to connect bone to muscle
how is composition of tendons different to that of ligaments
tendons contain less elastin than ligaments (because we want them to be more rigid)
what is bony congruence
the sum of surfaces that form an articulation
what does high bony congruence mean
the joint is stable
what does low bony congruence mean
the joint isn’t very stable and might need more soft tissue for support
what are the three joint classifications
fibrous - least amount of movement (skull sutures)
cartilaginous
synovial - most amount of movement (most limb joints)
what are fibrous joints composed of
DFCT - that functions to restrict movement and provide stability
what are cartilaginous joints composed of
fibrocartilage - structure varies but they all function to allow some movement
