bone Flashcards
what is the axial skeleton?
skeletal system
skull, spine, ribs, ears, kneck, breast
what are the appendicular bones
limb bones
examples of short bones
wrists
ankles
carpels
tarsels
exmaples of flat bones
skill
ribcage
scapular
pelvis
examples of irregular bones
verebrate
jaw
heel
examlples of sesmiud bones
patella knee cap
under big tow
thumb
how does the bone function for protections
axial skeleton surronds and protects much of the soft viscera
hert and lungs by ribcage
pelvis protects bladder
how does bone function as a framwork?
everything hangs off it using gravity
muscles, vicera, tissues al suspended from bones
how do bones help with movement
appendicular skeleton enables movement for survival
contractile muscle attaches via tendons to move the rigid bones round a pivit
what are joints
ligaments holding together two bones
muscles and tendons allow movement of the joint
what is a fibrous joint?
dont move anymore
bones that have since birth fused together
eg skull and base of shin bones
what is cartinaginout joitn
semi-moveable
joints at birth but later on fise they are secondary
what is a sinovial joint
freely moveable
hyaline cartilage
hinge, elbow, ball/socket saddle etc
examples of types of sinovial joints
hinge ball/socket pivot saddle conydoid sliding and gliding
how does bone act as a store
extracellular Ca is kept here
it can be put in the bones or taken back out when needed
what does calcitonin do?
takes calcium out of the blood into bones
what does the parathryoid hormone do
puts calcum into the blood
wher does calcitonin come from?
secreted by thyroid gland
where does the parathyroid hormone come from?
thyroid glad by back of neck
what does vitamin D do
moves calcum into the blood
what does calcitonin act on
osteoblasts to build bone by synthesising collagen and inorgaic consitidents
what does parathyriod hormone act on
osteoclasts to digest protein in lysosmones and to secrete acid to disolve the minerals
relasing Ca
how does vit D increase ca in the blood
acts on the gut to increase abription of Ca
if calcium levels drop what happens
thyriod gland activated parahyroid hormone actvates osteoclasts bone digested calcium released into the blood levels normalise
if calcium levels are too high what happens
thyroid gland activated calcitonin osteobalsts activated calcium is deposite in bone and built up levels normalise lower
what is the epiphysis
either end of long bones
knobbly bits on the ends
spongy bone
red marrow foud here
what is the diaphysis
shaft of the long bone
compact bone
yellow marrow
what is the mathaphysis
both the epiphysis and diaphysis meet here
epiphyseal plateq
what is the periosteum
covering of the bone
not found in joints though
where does the bone get a blood suply
1 artery comes into diaphysis
2 into each epiphyseal
branches off from here
main properties of bone:
hard but lightweight
flexible but rigid
adaptive
storage and remodelling
how is bone hard but light
compact cortical bone with a hard outer shel makes up most of the mass
also has spongy cancellous bone on the inside
what is compact bone like
called lamella bone
has rings called osteons
what are osteons?
concentric layers of lamellae surrnding a central haversian canal
where are the blood vessels in compact bone
in the hollow central haversian cancl
what are lacunae
cavities between the lameala where osteocytes sit
what is spongy bone like?
howwlow network of trabeculae
contains red marrow
large surface area for mineral exchange
what makes bone flexible but rigid
largely connective tissue
more inorganic matter but some organic which ismroe flexible
whats the role of collagen in bone
fibrous proteins
fibres extend the bones lines for foce and more bone is lai along this
what is ground substance
amorphou gelantinous:
pretoglycans, GAGs, fluid
how does ground substance withstand forces
attracts ctions
sucks in water
wtistands compressive forces
what makes bones rigid
deposition of salts and minerals
calcium and phosphates
hydroxyappatite
what sibstances make up boesn rididity
calcium andphosphate
inroganic csalts deposited in the organic matrix
small amonts of calcium carbonte and calcium fluride
can also take up lead and other metals sometimes
what is a tensile force
pulling and stretchnig
what is a torsional force
rotation
which force is bone better at dealing with
compression than tension
what are the stages of biochemiacs of bone
initial elastic phase
plastic phase
permanent shape
what happens in the initial elastic stage and plastic stages?
focce is applied to bone and its able to go back to its original shape
after a while though it wont go back to this shape and is in the plastic stage
bone features
strong
doesnt chang shape
breaks easily though
biochemianics of spongy bone
little bit of stresses ad it esily changes chape
its weaker but takes a wbile to break
more pilable
what makes bones flexible while also ridig
the mix of compact and spongy bone
they have different biochemiancs
what explains how bones are adpatable?
Wolffs law
bones will change shape and structure according to the stresses placed on the
what part of bones has high compressive strength
non-organic hydroyappative and water
what part of bones has a weak tensile strength
organic collagen fibres
what do oseoclasts do?
resorb/disolve the bone
sit on the bone and secrete enzymes to digest collagen and HCL for salts
what is in the osteoblast family?
osteobasts
osteocytes
osteopregenitor cells
what doe osteoblasts do
build bone
what do osteocytes do
mature osteoblasts that help maintain bone
what is an osteoprogenitr cells
lining cells that ocver the surface of the bone and cna become osteoclasts
how are osteoclasts formed
immature monocytes
become pre-steoclast
signals form bone cells tells it to become an osteoclast
goes its job
where is the osteblast family derrived from
messenchyme
embryonic cell that becomes connective tissue
bone marrow precursor
what do bones grow along?
cartilaginous templates for long bones
membranous template for flat bones
what is primary ossification
starts during foeatal development
cartilage is replaced with bone
at birth secondary ossification centres form that do not officy
in long bones hwat is the process of ossificaion called?
endochondral ossification
what is endorchonral ossification
cartinage template and bone laid dont over this
long oones speicifically
describe teh steps of catilage to bone in ossification
- bone collage formed around diaphysis by osteoblasts ]2. cartilage in primary centres calcifies and cavitied form in calsification
- periosteal bud enters cavity and builds spongy bone
- secondaryr ossification centre forms epiphysis. osteoclasts disolve sony bone creating medullary cavity
- hyaline remains on epiphysel surface to form plaates
spongy bone remains in the centre
where do long bones grow
at the epiphyseal plates
what makes cartilage
chrondroytes
what causees long bones to lengthen
catilage is made and pushes the bone further apart at the plates
what happpens to bones in adulthood?
coup;ed process of bone destruction and bone deposition
controlled by diet and hormones
prevents mineral crystalisation
when is out max bone density
30 years
what happens to bones as we age
reduced bone formation that cannot keep up with bone resoption leading to bone loss
what does osteoprosis lead to
poor posture, breathing/walking
moility issues with hips
wrist issues
how can you improve bone density
weight breaking exercises
diet
sunligh
what kind of diet can imporove bone density
right in clcium vitD, vit C, vit A
