12 Bone (Overview) Flashcards
How many bones are in the human skeleton?
206
What are the two skeletal structures making up the human skeleton?
The axial skeleton (skull, vertebral column and rib cage)
The appendicular skeleton (upper and lower limbs)
What are the 7 functions of bone?
support protection movement mineral growth and storage fat storage blood cell formation hormone production
what are the 5 types of bone?
long (humerus) short (only in ankle and wrist) sesamoid flat (sternum) irregular (vertebrae)
what are the 2 types of bone tissue?
compact / cortical
spongy / medullary
what are the 3 main segments of a long bone?
diaphysis (shaft)
metaphysis (flared segment between shaft and head)
epiphysis (head)
what is a medullary cavity?
found in the inside of the diaphysis of a long bone, contains yellow bone marrow (fat storage)
which parts of a long bone are formed by compact bone, and which by spongy?
compact bone forms the external layer of long bones
spongy bone forms the proximal head
what is the composition of compact bone?
made up of osteons (cylindrical layers of lamallae around Haversian canals containing blood vessels)
what is the composition of spongy bone?
lattice like structures of trabeculae, with bone marrow in the spaces
describe the process of endochondral ossification
all bones in the embryonic skeleton are formed of cartilage
cartilage calcifies around mid region of bone
primary ossification centre: in the diaphysis of long bone, forms bone to replace cartilage and grows as bone develops
secondary ossification centres: in the epiphysis of long bones
fusion of the first and second ossification centres occurs at the epiphyseal plate when the bone reaches its full length
what are the main cell types in bone?
osteogenic stem cells
osteoblasts (immature cells)
osteocytes (mature cells)
osteoclasts (clear old cells)
what is the external covering of bone, and its function?
periosteum
nourishes external aspects of bone
provides interface for attachment of tendons and ligaments
describe the vasculature of bones
bones are richly supplied with blood vessels
one or more nutrient arteries supplies the shaft of each long bone, through a nutrient foramina (a hole in the bone)
ends of long bones are supplied by metaphysial and epiphysial arteries
arteries divide inside medullary cavity into branches that supply the bone
blood reaches compact bone through Haversian canals
describe the innervation of bone
periosteum is supplied with sensory nerves that carry pain fibres and are sensitive to tearing or tension
bone itself is sparsely supplied with sensory endings
