tissues and structures Flashcards
how does bone growth begin?
a cartilaginous model like a ‘map’ for where bones will grow
endochondral ossification
the process of turning cartilage to bone within a cartilaginous model
primary ossification centers
the diaphysis, osteoblasts and blood vessels push inside the cartilage and begin to form bone
what is the secondary ossification centre?
epiphysis, same process as primary but is seperated from the diaphysis by the epiphysial (growth) plate
what is the function of the growth plate?
enabling bones to grow in length, when bones reach final length the epiphysis will fuse to the diaphysis
what is appositional growth?
bones growing in width to be able to support the weight of the body. enabled by osteoclastic and osteoblastic activity
what do chondrocytes do?
produce ECM of ground substance for cartilage
how does avascular cartilage get nutrients?
joint loading is ‘luck’, every time you move it pushes nutrients into the tissue in the hope cells can get it
hyaline (articular) cartilage function and structure?
resists compression due to high water content in the ECM, sparse collagen fibres and smooth rubbery tissue
what is hyaline cartilage used for?
found on articulating surfaces of bones for frictionless movement
what is the subchondral area?
the smooth bone that sits underneath the hyaline cartilage
what is fibrocartilage? (function and structure)
resists compression AND tension, many collagen bundles and orients fibres with stresses so that where tissues pull it resists and doesnt tear
where is fibrocartilage used in the body?
acts as a buffer or shock absorber at joints that experience compression and tension, the shape adds more surface contact to disperse force and support joints e.g. menisci in knee joint
what does DFCT stand for?
dense fibrous connective tissue
where is DFCT found?
ligaments, tendons, joint capsules
function of DFCT?
made of collagen and a little elastin tightly packed together to resist tension (has little vascularity)
what is a ligament?
collagen and elastin that connects bone to bone, resists tension and allows a little stretch and recoil, restricts movements away from itself
what is a tendon?
less elastin than ligaments, connects muscle to bone, facilitates and controls movement
bone congruence
sum of the bony surfaces that form articulation
less bony congruence = more soft tissue support needed
more bony congruence = more stable joint
