4a - Skeletal System; Bones Flashcards
Bone is a ________ _________ tissue
mineralised connective
bone extracellular matrix is
osteoid
c_______ of c_______ p_______ in osteoid
crystals of calcium phosphate
calcium phosphate crystals function in EM
hardness and rigidity
osteoid function
durability - bones not brittle
3 bone cells
osteoblasts, osteocytes and osteoclasts
osteoblasts location on bone
surface
osteoblast secrete …
osteoid
osteoblasts become…
trapped by bone they produce
osteocytes come from…
trapped osteoblasts
osteocytes location
lacunae (small cavities)
osteocytes function
maintain bone matrix
osteoclasts function
remove unwanted bone
2 types of bone
compact and spongy
compact bone strength
very hard and strong
compact bone forms the…
outer shell (cortex) of all bone
compact bone structure
dense, close-packed columns of bone in layers (central circle surrounded by other rings)
compact bone - centre of column is
Haversian canal
compact bone - center of column is
Haversian canal
what does the Haversian canal contain
blood vessels
nerves
name of column of bone and central canal
osteon / haversian system
spongy bone alternative name
cancellous
spongy bone strength
weaker than compact
spongy bone location
middle (medulla) of bones
long bone in ends not shafts
spongy bone structure
mesh of bony rods (trabeculae) with spaces between filled with bone marrow
ossification is
the formation of bone
when does bone formation happen
in fetus
during growth
after fracture
the formation of bone is called
ossification
how does ossification happen
deposition of calcium salts in matrix of osteoid tissue
in a dog fetus how many days until bone formation starts and what can it be seen on
45 days
x - ray
2 types of bone development
endochondral (most common)
intramembranous
endochondral ossification is… e.g….
cartilage model replaced by bone e.g. long bone
intramembranous ossification is… e.g….
osteoblasts lay down bone between two layers of fibrous tissue (no cartilage template) e.g. skull bones / flat bones
endochondral steps (1 -5)
- cartilage developed in foetus
- primary ossification starts in the shaft (diaphysis)
- secondary ossification starts in ends (epiphysis)
- two centres of ossification grow and expand to each other
- osteoclasts remove bone in the centre to create marrow cavity
what are growth plates
spaces filled with cartilage between epiphyses and diaphyses until mature - spaces allow for bone development and growth
X-rays bone and cartilage colour
bone = white
cartilage = black
on young aniamls x-rays will have ______ as ______ doesn’t show up
gaps
cartilage
intramembranous steps (1-2)
- two fibrous membranes with osteoblasts make osteoid
- calcifies to form bone
mature bone formation steps (1-3)
- most osteoblasts become osteocytes
- some held in reserve by periosteum and endosteum
- reserve osteoblasts form osteogenic layers
use of reserve osteoblasts
if fracture will allow for new bone to grow
periosteum is
membrane around bone
endosteum is
membrane in bone
fracture repair basic steps week 1
week 1 - haematoma (swelling with blood)
fracture repair basic steps week 2-3
week 2-3 - soft callus
fracture repair basic steps week 4-16
week 4-16 - hard callus
fracture repair basic steps week 17 and beyond
week 17+ - remodeling
skeletal system functions (1-5)
support
protection
locomotion
storage
hematopoiesis (new blood cell production)
bone shapes (5)
long
short
flat
irregular
sesamoid
specialised bone shapes (2)
pneumatic
splanchnic
long bones structure and location
length greater than width
found in limbs e.g. femur, humerus
short bones structure and location
length = width
found in carpal and tarsal bones
flat bones location
in skull
irregular bones structure and location
non-uniform shapes
found in vertebrae
sesamoid bones structure and location
sesame seed
develop in tendons
found in patella (kneecap)
pneumatic bones structure and location
air filled cavities
found in frontal bones e.g. sinuses
splanchnic bones location
unattached to skeleton
only example is the os penis (dogs do, some cats dont)
skeleton components (3)
axial
appendicular
splanchnic
axial skeleton components (4)
skull bones of head
vertebral column
ribs
sternum
appendicular skeleton components (2)
pectoral and pelvic limbs
shoulder & pelvic girdle
splanchnic skeleton components
bones in soft tissue - os penis