Skeleton System Flashcards
the skeletal system includes
bones
cartilages
ligaments
connective tissues
what are the functions of the skeletal system
support mineral storage (calcium) lipid storage (yellow marrow) blood cell production (red marrow) protection leverage
how are bones classified
shape bone markings (on the surface)
what are the different bone shapes
long bones flat bones sutural bones irregular bones short bones sesamoid bones
long bones
long and thin found in arms legs hands feet fingers and toes
flat bones
thin with parallel surfaces found in skull sternum ribs and scapulae
sutural bones
small irregular bones found between flat bones of the skull
irregular bones
complex shapes e.g. spinal vertebrae, pelvic bones
short bones
small and thick e.g. ankle and wrist bones
sesamoid bones
small and flat develop inside tendons near joints of knees hands and feet
process
any projection or bump
ramus
an extension of a bone making an angle with the rest of the structure
trochanter
a large rough projecton
tuberosity
a smaller rough projection
tubercle
a small rounded projection
crest
a prominent ridge
line
a low ridge
spine
a pointed or narrow process
head
the expanded articular end of an epiphysis and the diaphysis
condyle
a smooth rounded articular process
trochlea
a smooth grooved articular process shaped like a pulley
facet
a small flat articular surface
fossa
a shallow depression
sulcus
a narrow groove
foramen
a rounded passageway for blood vessels or nerves
canal or meatus
a passageway through the substance of a bone
fissure
an elongated cleft
sinus or antrum
a chamber within a bone normally filled with air
what are the structures of a long bone
diaphysis
metaphysis
epiphysis
diaphysis
the shaft
heavy wall of compact bone or dense bone
medullary (marrow) cavity
central space inside the long bone
epiphysis
wide part at each end
articulation with other bones
mostly spongy bone (cancellous)
covered with compact bone (cortex)
metaphysis
where the diaphysis and epiphysis meet
flat bone structure
resembles a sandwich of spongy bone
bread is two layers of compact bone
bone tissue
dense supportive connective tissue
contains specialized cells
produces solid matrix of calcium salt deposits
around collagen fibers
osteon
bone cells within lacunae organized around blood vessels
canaliculi
form pathways for blood vessels
exchange nutrients and wastes
periosteum
outter linning
covers outer surfaces of bones
consists of outer fibrous and inner cellular layers
endiosteum
inner linning
cells of bone make up what % of bone mass
2%
bones contains four types of what cells
osteocytes
osteoblasts
osteoprogenitor cells
osteoclasts
osteocytes
mature bone cells that maintain the bone matrix
live in lacunae
connect by extensions thru canaliculi in lamellae
do not divide
what are the functions of osteoclasts
maintain protein and mineral content of matrix
help repair damaged bone
osteoblasts
bone making cells
immature bone cells that secrete bone (osteogenesis)
produces osteoid-matrix but not yet calcified to formed bone
become osteocytes once done secreting bone
osteoclasts
derived from stem cells
secrete acids and protein-digesting enzymes
giant multinucleate cells
dissolve bone matrix and release stored minerals (osteolysis)
osteoprogenitor cells
mesenchymal stem cells that divide to produce osteoblasts
located in endosteum
assist in fracture repair
precursor cells sitting in wait for something to happen
cells that become something else
osteon
basic unit of compact bone
central canal contains blood vessels
perforating canals carry blood vessels into bone and marrow
circumferential lamellae
wrapped around the long bone
bind osteons together
spongy bone
no osteons
matrix formed by trabeculae (swiss cheese)
space between filled with red & yellow marrow
red marrow
has blood vessels
forms red blood cells
supplies nutrients to osteocytes
yellow marrow
in some bones
stores fat
weight bearing bones
femur tension on lateral side compression on medial side (femur)
functions of periosteum
isolate bone from surrounding tissues
provide route for circulatory & nervous supply
participates in growth & repair
endosteum
lines medullary cavity (marrow) covers trabeculae of spongy bone lines central canals contains osteoblast osteoprogenitor cells osteoclasts active in bone growth & repair
bone development
during first month of embryonic development tissue replaced with bone with 2 processes
what are the 2 processes of fetal bone development
intramembranous ossification
endochondral ossification
intramembranous ossification
fibrous membranes replaced with bone
occurs in flat bones like skull, sternum
endochondral ossification
hyaline cartilage replaced by bone
occurs in most bones-long bones
steps of intramembranous ossification
spongy bone develops at certain ossification sites
red bone marrow forms in spongy bone tissue
compact bone forms on the outside
steps of endochondral osssification
cavity formed in hyaline cartilage at primary ossification center
influx of osteoblasts, osteoclasts, red marrow, nerves, blood called periosteal bud
osteoclasts break down new spongy bone forming medullary cavity
compact bone replaces cartilage on outside
2nd ossification center & periosteal bud forms at epiphysis
articular cartilage forms on outside of epiphysis
cartilage remains between both ossification centers - growth
what growth occurs at epiphyseal plate
chondrocytes divide producing new cartilage at epiphyseal end
old cartilage replaced broken down by osteoclast replaced by bone
appositional growth
compact bone thickens and strengthens long bone with layers of circumferential lamellae
epiphyseal lines
when long bones stop growing after puberty
epiphyseal cartilage disappears
visible on x-ray as lines
mature bones
osteoclast enlarge medullary cavity
osteons form around blood vessels in compact bone
3 major sets of blood vessels develop
nutrient artery and vein
metaphyseal vessels
periosteal vessels
nutrient artery & vein
single pair of large blood vessels
enter diaphysis thru nutrient foramen
femur has more than one pair
metaphyseal vessels
supply epiphyseal cartilage
where bone growth occurs
periosteal vessels
provide blood to superficial osteons
provide secondary ossification centers
bone remodeling
ongoing process
involves osteocytes osteoblasts osteoclasts
remodels recycles replaces
turnover rate varies
wolfs law
heavily stressed bones become thicker and stonger
nutritional & hormonal factors
vitamin c for collagen synthesis osteoblast differentiation stimulation
vitamin a stimulates osteoblast activity
vitamin k b12 synthesize bone proteins
growth hormone & thyroxine stimulate bone growth
estrogens & androgens stimulate osteoblasts
calcitonin & parathyroid hormone regulate calcium & phosphate levels
What is the need for calicum
membranes
neurons
muscle cells especially heart
how is calcium homeostatis achieved
by calcitonin and parathyroid hormone
control storage absorption and excretion
calcitonin and parathyroid hormone impact
bones where calcium is stored
digestive tract where calcium is absorbed
kidney where calcium is excreted
PTH
produced by parathyroid glands in neck increases calcium levels stimulates osteoclasts increasing intestinal absorption of calcium decreasing calcium excretion at kidneys
calcitonin
secreted by c cells in thyroid
decreases calcium ion level
inhibits osteoclast activity
increasing calcium excretion at kidneys
potts fracture
occurs at ankle affects both bones of leg
comminuted fracture
shattering the affected area into multitude of bony fragments
transverse fracture
break a bone shaft across its long axis
spiral fracture
fractures produced twisting stresses that spread along the length of the bone
displaced fracture
fractures that are not in alignment
colles fracture
a break in the distal portion of the radius a result of reaching out to cushion a fall
greenstick fracture
fractures when only one side of the shaft is broken and the other is bent
epiphyseal fracture
clean transverse fracture along the epiphysis
compression fracture
bones are crushed force is extreme
fracture repair
bleeding produces clot
establishes fibrous network
bone cells in area die
endosteum & periosteum cells divide go to fracture zone
clean up debris & calluses stabilize break
osteoblasts replace central cartilage of external callus with spongy bone
osteoblast osteoclast osteocytes remodel fracture for up to a year reducing bone calluses
