osteology Flashcards
skeletal system is composed of…
bones, cartilage, and ligaments
cartilage
precursor for most bones. cover joint surfaces
ligaments
holds bone to bone together
tendons
attaches muscle to bone
functions of the skeletal system
provides structure/support, protection, site of blood cell formation, essential for movement, storage of minerals
bone marrow
softer connective tissue that fills the interior of most bone
why is bone marrow important?
serves as a site for fat storage and blood cell production
yellow marrow
contains adipose (fat) tissue + serve as a source of energy
red marrow
location of blood cell production (RBCs, WBCs, + platelets)
hematopoiesis
the production of blood cells
how many bones are in an adult skeleton?
206 bones
long bones
longer than wide, cylindrical, used for leverage
what type of bone does hematopoiesis occur in children?
long bones
short bones
roughly cube shaped, found where stability/support/mobility is needed
flat bones
thin bones, broad surface for muscle attachment
what type of bone does hematopoisis occur in adults?
flat bones
irregular bones
irregular shapes with numerous projections
pneumatic bones
contain air spaces (sinuses), reduce the weight of the skull
sesamoid bones
small round bones embedded within a tendon
axial skeleton
bones of the skull, hyoid, vertebral column, and rib cage
how many bones are in the axial skeleton?
80 bones
appendicular skeleton
bones of the limbs, pectoral girdle, and pelvic girdle
how many bones are in the appendicular skeleton?
126
cranial skeleton
bones of the skull
post-cranial skeleton
bones of the vertebral column
how many bones are in the skull?
22 individual bones
how many cranial bones?
8
how many facial bones?
14
disphysis
body/shaft of the bone
where is the primary center of ossification (in utero)?
diaphysis
epiphysis
ends of the bones that articulate with different bones
where is the secondary center of ossification (in puberty)?
epiphysis
metaphysis
where diaphysis and epiphysis meet
epiphyseal plate
connects diaphysis to epiphysis. composed if hyaline cartilage
what is another name for the epiphyseal plate?
growth plate
periosteum
fibrous structure covering outer bone surfaces
where is the periosteum absent?
articular bone surfaces + where tendons/ligaments attach
periosteum layers
fibrous and cellular
fibrous layer of periosteum
superficial. sheets of dense irregular connective tissue
what is in the connective tissue of the fibrous layer?
type 1 collagen fibers, fibroblasts, blood vessels, lymph vessels, nerve fibers
cellular layer of periosteum
deep. thin layer containing bone cells
endosteum
thin connective tissue layer covering inner bone surfaces
what type of bone cells are in endosteum?
osteoprogenitor cells + osteoblasts
medullary cavity
cavity at the center of long bones. aka marrow cavity
articular cartilage
hyaline cartilage covering articular/facet surfaces
woven bone
newly calcified. develops when a fetus and when repairing a fracture
what is another name for woven bone?
primary bone
spongy/trabecular bone
inner layer of porous bone. located at the end of long bones
compact/cortical bone
outer layer of densely packed bone tissue. contains haversian system
spongy/cancellous/trabecular bone
in the interior of bone
subchondral bone
very thin layer of modified compact bone
where is subchondral bone found?
underlying articular cartilage
osteons (haversian system)
cylindrical units of bone tissue, packed together tightly
lamellae
concentric layers of bone tissue
central canal
contains vascular structures and nerves
lacunae
holes between lamellae
canaliculi
passages connecting lacunae to each other
perforating/communicating/volkmann’s canals
connecting central canals together
circumferential lamellae
multiple sheet-like layers of bone tissue
external circumferential lamellae
located immediately deep to the periosteum
inner circumferential lamellae
located at the perimeter of the medullary cavity
interstitial lamellae
layers of bone tissue, between osteons
bone matrix fibers
90% type 1 collagen, 10% ground substance
bone salts
inorganic component in bones
what are the most common bone salts?
calcium + hydroxyapatite
purpose of bone salts
provides strength to resist compressive forces
what type of strength do collagen fibers provide?
tensile strength
osteoprogenitor cells
bone stem cell. give rise to osteoblasts
osteoblasts
build new bone
osteocytes
former osteoblasts that maintain bone tissue + mineral content
osteoclasts
destroy bone
what does bonding between collagen + hydroxyapatite prevent?
bone shearing/sliding
place bone calcification steps in order of how they occur…
1. collagen monomers polymerize to form collagen fibers
2. osteoblasts secrete collagen molecules + ground substance
3. nidi multiply and grow
4. amorphous calcium salts are remodeled into hydroxyapatite crystals
5. calcium salts precipitate in osteoid
6. nidi of amorphous compounds form at intervals
2, 1, 5, 6, 3, 4
place bone remodeling steps in order of how they occur…
1. enzymes digest/dissolve organic matrix of bone
2. osteoclasts embed small particles of bone and crystals by phagocytosis
3. osteoclasts eat bone away to create a tunnel
4. osteoclasts send out villus-like projections
5. acids dissolve bone salts
6. new bone begins to develop
7. villi-like projections secrete proteolytic enzymes + acids
4, 7, 1, 5, 2, 3, 6
what does pyrophosphate inhibit?
hydroxyapatite crystallization + bone calcification
endochondral ossification
bone formed from preexisting cartilage
interstitial growth
growth of bones in length occuring at epiphyseal plate
appositional growth
growth of bone in thickness/width
intramembranous ossification
bone formed from connective tissue
what stops bone growth?
human growth hormone
wolff’s law
bone remodels its shape according to the way force is transmitted through it
