Endocrinology - introduction to bones Flashcards
What makes up main components of musculoskeletal system?
muscle, bone skeleton
What are 3 parts of connective tissue ?
What are their function?
tendon - joins muscle to bone
ligaments - connect bone to bone
cartilage - structural support, protect tissues, attachment sites
What are 2 types of bones?
Flat and long bones
What are 5 functions of skeleton?
Support, protection, movement, storage of Ca and phosphate, produce blood cells
How do you produce each bone type?
Flat - intramembranous mesenchymal cells converted into bone
long - endochondral mesenchymal to cartilage to bone
What is the process to produce flat bones called?
intranmembranous ossification
What is process of IO?
mesenchymal cells in connective tiusse condense and differintate into osteoblasts
they secrete oestoid that causes osteblasts to bcome oestocytes
ossification centre fuse together to form trabecular matrix (SPONGY BONE)
on outer surface mesenchyma cells fuse togehter stongly to form periosteum
then compact bone develops on outside of cancellous (spongy) bone. And crowded blood vells condense into red bone marrow
https://www.youtube.com/watch?v=gh6J2CHR_q4
What is the process to form long bones?
Endochondral ossification
development of long bone from hyaline cartilage model
1st Stepsof endochondral ossification?
1st - formation of collar bone by invading of blood vessles that cause osteoblast to be formed and release bone matrix
(this area of activity called primar oesification centre)
2nd Stepsof endochondral ossification?
cavitation - chondryctes enlarge + send signal for cartilage to calicfy
causes matrix to become impermable to nurtients and die + central clearing
3rd step of EO?
periosteal bud invasion- invades cavity and causes spongy bone to be made also delivers osteoclasts(remove cartilage) and blasts (produce spongy bone)
4th step of EO?
diaphysis (primary ossification centre) - enlarging mainly spongy bone
5th step of EO?
secondary ossification centres epihpyseal forms and only start to ossidify after birth
cartilage only remains at bone surface and at epiphyseal plates
what are bones made up of?
matrix and cells
What cells are bone stem cells?
osteogenic cell
What are osteoblasts and where are they found?
bone forming cells, secrete osteoid
cause minerealisiation of oesteoid
Found in growing portions of bone such as periosteum and endosteum
What are osteocytes and where are they found?
matyre bone cells, when osteoblasts imbedded in its secretions.
senses strain to direct osteoblast/clast activity
found entrappped in matrix
What are osteoclasts and where are they found
bone breaking, dissolve bone by phagocytsosis, derived from bone marrow
found: bone surfaces and sires of old injured or unneeded bone
What makes up bone matrix?
Organic components - T1 collagon, ground substace like proteoglycans and glycoproteins and cytokines
inorganic component - calcium hydroxyapatite, osteocalcium phosphate
What are types of bone?
immature - first bone layed down and in woven manner quite weak. becomes replaced by mature
mature bone - mineralized woven bone, lamellar (layer) structure - v strong
2 types of mature bone?
- cortical/lamellar, compact and strong
- cancellous/spongy - honeycomb strucutre, not suitable for weight baring activity
How doe cortical and cancellous present in bones of body?
cortical - shell on outside, the unit of one is osteon
How is cortical bone organized?
repeated units of ‘osteons’
lamellae around a ‘haversian central’ - contains blood, vien and nerve
lacunae - small spaces containing osteocytes, tiny canaliculi radiate from lacunae filled with EC fluid
volkmans canal - transverse perforating canals
Label diagram
periosteum - connective covering
outer cortex - compact bone
medullary cavity - yellow bone marryow
articular cartilage - surface of bone at joints
What is the growth plate in long bones?
physeal bone plate
What are 2 types of bone growth?
insterstital - long bones only and increase in lnegth
appositonal - mainly children and increase thickness and diameter
How do long bones grow? (intersititial)
physeal plate, that normally has hylaine cartilage
epiphyseal side - hyaline cartilage divide form hyaline cartilage matrix
diaphyseal side - cartilage calcifies and dies replaced by bone
What is mechanism of appositional growth?
deposition of bone beneath periosteum to increase thickness
Steps of appositional growth?
- ridges in periosteum creates groove for periosteal blood vessel
- ridges fuse and form endosteum lined tunnel
- osteoblasts in endosteum build new lamellae towards centre of tunnel new osten
- bone grow outwards as osteoblasts in peristeum build new lamellae. osteon formationrepeated as new periosteal ridges.
What are 3 types of joints?
Fibrous joints (also sutures) are joints in which bones are joined by dense connective tissue.The joints between bones of the cranium
Cartilaginous joints are joints in which bones are joined by cartilage. (vertebrae in the spine)
Synovial joints are characterized by a fluid-filled space, called a synovial cavity, between the bones of the joints.
What are the joints that come under synovial joint?
Which joint is most common and mobile?
Synovial joint
What is structure of joint capsule?
articular capsule (outer) that keeps bones togehter
synovial membrane(cavity) - contains synovial fuild
secreted by synovial lining
SF - reduce friction, high liubrication
How are synovial joints stabilized?
By muscle/tendons
ligaments
bone surface conguirty
How do ligaments stabilise a joint?
prevent excessive movement that damage to a joint
the more and tighter —-> greater stability + LESS mobility
(less stability more risk of dislocation)
What ligaments laxity?
And how can it an affect
(usually natural) loose ligements
leads to hypermobility and greater risk of injury
Factors affecting stability?
joint articular
joint capulse
ligaments
muscles
moblity
Compare Hips Vs shoulder
