bones, skeleton and joints Flashcards
what are the 6 functions of bones?
- support - bones provide the hard framework that supports the weight of the body
- movement - skeletal muscles attach to bones and use them as the levers to move
- protection - e.g. the cranial bones protect the brain
- mineral storage - bones are reservoir for minerals, importantly calcium and phosphate
- blood cell formation and energy storage - red bone marrow makes red blood cells (hematoposis) yellow bone marrow stores fat
- energy metabolism - osteoblasts secrete osteocalcin (plays a role in blood sugar regulation)
what are osteoblasts ?
cells that actively produce the bone matrix
what are osteocytes ?
keep bone matrix healthy, maintain bone matrix
what are osteoclasts ?
break down bone matrix
what are the four classifications of bone shape?
and provide examples
long - humerus
short - talus
flat - sternum
irregular - vertebrae
what is the periosteum?
a connective tissue membrane that cover the entire outer surface of each bone except on the ends
what is a tuberosity ?
large rounded projection
what is a crest?
narrow ridge of bone; usually prominent
e.g. the lilac crest of the hip bone
what is a line ?
a narrow ridge of bone less prominent than a crest
what is a tubercle ?
small rounder projection or process
what is a head?
boney expansion carried on a narrow neck
what is a facet?
smooth, flat articular surface
what is a meatus?
canal -like passageway
e.g. the external and internal auditory meatus on the temporal bone
what is a fossa?
a shallow basinlike depression in a bone
what is a sinus?
cavity within a bone, filled with air and lined with mucous
what is the name given to the formation of bone-tissue?
osteogenesis and ossification
what is endochondral ossification?
the process in which hyaline cartilage is replaced with bone matrix
what are the five steps of endochondral ossification?
- a bone collar forms around the diaphysis
- cartilage calcifies in the centre of the diaphysis
- the periosteal bud invades the diaphysis and the first bone tracbeculae forms
- diaphysis elongates and the medullary cavity forms
- epiphyses ossify and cartilaginous epiphyseal plates separate diaphysis and epiphyses
what is the epiphyseal plate?
between diaphysis and epiphysis
aka the growth plate
responsible for lengthening
bones during the two decades following birth
what are the five zones of the epiphyseal plate/growth plate?
reseting zone
profliferation zone - chondroblasts at the top divide quickly pushing diaphysis anway from epiphysis, elongating the bone
hypertrophic zone - older chondrocytes in the stack enlarge and send signal to calcify
calcification zone - cartilage matrix becomes calcified
ossification zone
bone deposition is accomplished by ….
osteoblasts
bone resorption is accomplished by ….
osteoclasts
what is the most complex bony structure ?
the skull
what are the cranial bones/cranium/skull cap ?
there are 8 cranial bones, these bones enclose and protect the brain occipital sphenoid parietal (2) temporal (2) ethmoid frontal