bone struture and function Flashcards
what are the 4 types of bones
long
short
flat
irregular
describe the shape of long bones
longer than wide
examples of long bones
thigh, arm, fingers, toes
describe the shape of short bones
almost cube shaped
examples of short bones
wrists and ankles
describe shape of flat bone
thin and extensive surface
examples of flat bones
cranial, ribs
examples of irregular bone
vertebrae and some facial bones
what is the diaphysis in a long bone
the shaft
what is the epiphysis in a long bone
terminal portion
what is the metaphysis in a long bone
vascular region adjoining epiphyseal cartilage
what is articular cartilage in a long bone
situated at a joint
what is a periosteum in a long bone
fibrinous membrane
what is a medullary cavity in a long bone
central hollow space
what is an endosteum in a long bone
membrane lining inner cavity
what is the matrix of a long bone made up of
25% water, 25% collagen fibres, 50% crystalized mineral salts
where are osteogenic cells found
in periosteum
what do osteogenic cells develop into
osteoblasts
what do osteoblasts do
secrete collagen fibres
what do osteoblasts become
osteocytes
what do osteocytes do
maintain bone
what are osteoclasts formed from
monocytes
what do osteoclasts do
digest bone matrix for normal bone turnover
how much of bone structure is compact
80%
what units make up compact bone
osteons
where does the compact bone lie
below the periosteum
what makes up the central canal of compact bone
blood vessels, nerves, lymphatics
what is the concentric lamellae in the compact bone
layers of matrix
what are lacunae in compact bone
“lakes” containing osteocytes
what are canaliculae in compact bone
little canals that nutrients flow in
what are volkmanns canals
canals that run from the outside of the bone to its interior
how much of bone is spongy bone
20%
what units make up spongy bone
trabeculae
what is in the spaces between trabeculae
red marrow
which organelle does spongy bone not include
osteons
name 3 functions of bone
support
protection
leverage
mineral homeostasis
blood cell production
triglyceride (fat) storage
what are calcium blood levels controlled by
negative feedback loops
how does the parathyroid hormone control blood calcium level
increases osteoclast activity
decreased loss in urine
how does calcitriol from kidneys control blood calcium level
increases absorption of calcium in the blood
how does calcitriol from thyroid glands control blood calcium level
decreased osteoclast activity
