Cartilage and bone Flashcards
name the things that can affect regulation of cartilage growth
stimulate protein synthesis
retard protein synthesis
tumours
describe what stimulates protein synthesis for cartilage growth
growth hormone - regulates cartilage growth (leads to bone growth)
thyroid hormone
testosterone
describe what retards protein synthesis for cartilage growth
corticosteroids
estradiol
retinoids (vitamin A, reduced growth)
describe what effect tumours have for cartilage growth
chondroma
chondrosarcoma
if chondrogenic layer is messed up - leads to tumours (POLARITYYY)
what is one of the hardest tissues of body
bone
can withstand lots of stress
what is ecm of bone made of
calcified material
type 1 collagen
describe the type 1 collagen of bone - what it does
helical structure
length of long bones
allows bones to bend without breaking
name the 4 cell types in bone
osteoprogenitor cells
osteoblasts
osteocytes
osteoclasts
describe osteoprogenitor cells
committed stem cells - already on lineage to become osteoblasts, cytes or clasts
describe osteoblasts
synthesize organic components of matrix
describe osteocytes
found in lacunae - trapped in ecm of bone
describe osteoclasts
multinucleated cells
involved in bone resorption (remodelling) - reabsorb calcium in bone
own line of differentiation
what is ecm of bone produced by
osteoblasts
describe components of ecm of bone
fibers - collagen type 1
ground substance - proteoglycans, glycoproteins
minerals - crystals of hydroxyapatite (Ca10(PO4)6(OH)2)
name the 2 glycoproteins found in ecm of bone
sialoprotein
osteocalcin
describe histological techniques for bone
special technique
called decalcification
5% nitric acid or ETDA treatment
remove calcium from bone so its easier to cut - left with a rubbery material
name the 3 classifications of bone
gross appearance
microscopy appearance
development appearance
describe gross appearance of bone
compact
cancellous (spongy)
describe microscopy appearance of bone
woven (immature)
lamellar (mature)
describe development appearance of bone
intramembranous- come from membrane of mesenchymal cells
endochondral - ossification of cartilage
what is epiphysis and diaphysis
epiphysis = top
diaphysis = bottom
why is calcium important
cofactor for metabolic processes
is compact bone mature
um yes
what do long bones come from
cartilage
describe periosteum
dense irregular ct
forms sheath around bone
fibrocytes - stuck in matrix
collagen type 1 fibers
some osteoprogenitor cells
describe outer circumferential system
lost of extracellular space
3-4 layers of osteocytes
parallel to periosteum - around bone
describe inner circumferential system
osteocytes
2-3 layers
on top of endosteum
describe endosteum
1 layer of osteoprogenitor cells
flat
closest to bone marrow
what is system aka
lamellae
what is an osteon
haversian system
describe interstitial system
between haversian systems
old haversian systems being turned over and uptaken
circular radial pattern
describe volkmann’s canal
horizontal
drains into bone marrow space
describe haversian canal
run lengthwise through bones
nerves go through here
describe haversian system
osteocytes
tunnels run through them
describe trabecular bone
looks cuboidal
osteoblasts makes ecm and fivers and divide or differentiate to osteocytes that are trapped in matrix
osteoclasts on side - round and big, multiple nuclei, breaks down ca
describe precisely where collagen fibers are in bone
wrap around haversian systems and interstitial (can be degraded - contents are recycled)
contribute to tensile strength - go up and down
how are osteons separated
cementin line - made up of protein cementin
goes around osteon and delineates one haversian system from another
describe how nutrients pass through osteocytes
pass from cell/layers then catabolic material must go back to blood supply so osteocytes can form canaliculi
what are canaliculi
channels with cellular processes
how nutrients are delivered to osteocytes at cementin line
how do osteocytes form canaliculi
osteocytes send out cellular processes and tentacles - makes up the canaliculi
bind and communicates with cell in next layer
what do osteoclasts first do
sit down on bone matrix and fuses - makes ruffle border
makes circumferential clearing zone which protects cell
what do lysosomes do (osteoclasts)
carry proteins made from nucleus golgi - packaged and lysosomes send their packages (contents) in to zone
what else does it (osteoclasts) send out that is important
sends out acid phosphatsases - protein made in nucleus RER - packaged by lysosomes and finds its way to zone
packs zone with acid phophatases
what happens after area is packed with acid phosphatases
cell uses carbonic anhydrase to make area acidic, since acidic phosphotases need an acidic environment to work
pumps H+ into zone, while it ships off bicarb to be removed
makes acidic environment
what happens after osteoclasts chew up bone
ca gets transported through osteoclasts and up blood stream
blood is being monitored for calcium concentration
