skeletal Flashcards
the skeleton
composite structure of bone, cartilage, ligaments, and other connective tissues to stabilize and connect bones
cartilage
semi rigid CT
3 major fxns of cartilage
support soft tissue, gliding surface for articulations, model for bone formation
3 types of cartilage
hyaline, fibrocartilage, elastic
chondroblasts
make cartilage
chondrocyte
mature cartilage cell that maintains matrix and tissues overall health and viability
hyaline cartilage fxn
support, flexibility
fibrocartilage fxn
tensile strength due to parallel thick collagen fibers
elastic cartilage fxn
flexibility and support
most abundant cartilage
hyaline
cartilages that contain perichondrium
hyaline and elastic
interstitial growth
growth from within
appositional growth
growth along periphery or outside edge
type of growth that occurs during embryonic development
interstitial and appositional
bone is primarily composed of … tissue
osseous
fxns of bone
support and protection, movement, blood cell formation, storage of calcium and energy (fat)
long bones
longer than wide
short bones
length and width similar
sesamoid bone
flat bones
thin, usually curved
irregular bones
elaborate, complex shape
condyle
large smooth rounded oval surface
facet
small flat shallow surface
head
prominent rounded epiphysis
trochlea
smooth grooved pulley like process
alveolus
deep pit or socket in the maxillae or mandible
fossa
flattened or shallow depression
sulcus
narrow groove
crest
narrow prominent ridgelike projection
epicondyle
projection adjacent to a condyle
line
low ridge
process
any marked bony prominence
ramus
angular extension of a bone relative to the rest of the structure
spine
pointed slender process
trochanter
massive rough projection found only on the femur
tubercle
small round projection
tuberosity
large rough projection
canal
passage way through a bone
fissure
narrow slit like opening through a bone
foramen
rounded passageway through a bone
meatus
passageway through a bone
sinus
cavity or hollow space in a bone
diaphysis
leverage
epiphysis
strengthen joints, SA for attachment
metaphysis
epiphyseal line or epiphyseal growth plate, depending on age, site of growth (length)
articular cartilage
hyaline cartilage without perichondrium
medullary cavity
hollow part of diaphysis that contains red and yellow marrow cavity, vasculature, innervation
endosteum
connective tissue on inside of bone that contains osteoprogenitor cells, osteoblasts, and osteoclasts
periosteum
dense irregular connective tissue on outside of bone
cellular inner layer and fibrous outer layer
protects and insulates bone, anchors vessels and nerves, osteoprogenitor cells, osteoblasts
perforating fibers
arise from periosteum and help anchor periosteum to diaphysis, meets articular cartilage on each side
osteoprogenitor cells are derived from
mesenchyme
cells involved in bone resorption
osteoclasts
osteoblasts
secrete HCl which dissolves calcium and phosphate which goes into canaliculi and is eventually picked up by lymph and blood
osteoclasts
have lysosomes which secrete enzymes that dissolve the organic component of matrix, use acid snd digestive enzymes to degrade bone
inorganic components of bones
ca, k, na, mg, carbonate, phosphate
hydroxyapatites
osteon fxn
strength, protection against twisting/torque
fxn of spongy bone
cross bracing, reduce weight, support and protect marrow
ossification of bony skeleton begins at around…
8 weeks of development
ossificstion in adults is used for…
remodeling and repair
osteogenesis
physical process of bone formation
ossification
replacing other tissue with bone
calcification
deposition of calcium salts
dermal ossification
process by which bone develops within a mesenchymal or fibrous CT
primary bone
aka woven bone
formed first in dermal ossification
immature and not well organized
secondary bone
aka lamellar bone
compact and spongy bone
periosteum formed
short bone ossification centers
only has primary ossification centers
irregular bones ossification centers
only have primary ossification centers but in many different places
long bone ossification centers
primary and secondary ossification centers
zone 1 of interstitial growth
healthy normal hyaline cartilage, secure epiphysis to epiphyseal plate
zone 2 of interstitial growth
growth in size and numbers, arrange in longitudinal columns, lacunae flatten
zone 3 of interstitial growth
increase in size but stop proliferating, lacunae thinning out, pushes epiphyseal end away from epiphyseal growth plate
zone 4 of interstitial growth
calcification, minerals are deposited in the matrix column between cells, cut down nutrient flow, chondrocytes die
zone 5 of interstitial growth
walls of lacunae break down, form longitudinal columns/channels which are invaded by capillaries and osteoprogenitor cells, lay down bone matrix on calcified columns, use matrix as template
prior to and throughout puberty bone undergoes
bone formation more than resorption
in mature adults bones undergo
resorption more than bone formation
appositional growth occurs within … and along …
periosteum, medullary cavity
bone remodeling is stimulated by
stress
bone remodeling occurs at … and … surfaces
periosteal, endosteal
bone is a … organ
mechanosensitive
mechanosensitive
alters structure to suit its mechanical environment
mechanotransduction
process by which physical forces are converted into biochemical signals which are integrated into cellular responses
vessels and nerves in bone enter through…
periosteum
nutrient vessels
supply diaphysis and enter central canals of osteons within compact bone and marrow cavity
metaphyseal vessels
supply diaphysial side of epiphyseal plate
epiphyseal vessels
supply epiphysis
periosteal vessels
supply superficial osteons within compact bone at external ends of shaft, enter perforating canals within shaft
nerves enter bone accompanying blood vessels through the…
nutrient foramen
growth hormone
stimulate liver somatomedins that directly stimulate cartilage growth at epiphyseal plate
thyroid hormone
influences the basal metabolic rate of bone cells
calcitonin (CT)
encourages Ca deposition into bone; depresses osteoclast activity
parathyroid hormone (PTH)
stimulates osteoclast activity to resorb bone
sex hormones
dramatically accelerate bone growth, stimulate osteoblasts at epiphyseal plate, signals EP closure at puberty
glucorticoids
normal levels no effect but if chronically high, increase bone resorption
vitamin A
activates osteoblasts
vitamin C
required for normal cartilage synthesis
vitamin D
stimulates absorption and transport of Ca and P ions into blood
bone gains strength in response to … due to increase in …
mechanical stress, amount of mineral salt deposition and collagen fibers synthesized
fracture repair steps
- blood clot
- soft callus forms
- hard callus forms from osteoblasts laying primary bone
- osteoclasts remove excess bony material and compact bones replace primary bone
potts fracture
ankle, both bones of leg
comminuted fracture
shatter into multitude of bony fragments
transverse fractures
break across long axis of shaft (across width)
spiral fractures
from twisting stresses, spread along the length of the bone
displaced fractures
produce new and abnormal bone arrangements
nondisplaced fractures
retain normal alignment of the bones of fragments
colles fracture
break in the distal portion if the radius, typically from reaching out to cushion a fall
greenstick fracture
only one side of shaft is broken and the other side is bent, typically occurs in children
epiphyseal fracture
bone matrix is undergoing calcification and chondrocytes are dying
compression fracture
vertebrae subject to extreme stresses such as landing on butt
aging affects bones in 2 ways:
tensile strength decreases, loss of Ca and other minerals
osteopenia
bone mineral density is lower than normal peak bmd, but not low enough to be classified as osteoporosis
pagets disease
old bone breakdown > new bone synthesis, body responds by making bone faster, but weaker softer bone
