chap 6 bone and skeletal Flashcards
what is the composition of the skeletal system?
bones
joints with cartilage, tendons, and ligaments
what does a ligament connect?
bone to bone
what does a tendon connect?
bone to muscle
what are the 3 types of cartilage?
hyaline
elastic
fibrocartillage
hyaline
provides firm support with some flexibility
where is hyaline cartilage found
articulate cartilage at ends of bones
costal cartilages
respiratory tract, voice box, nasal
elastic cartilage
stretch flexibility
where is elastic cartilage found?
ears
epiglottis
fibrocartillage
strength from collagen fibers but cushioning ability as well
very thick fibers
where is fibrocartillage found?
knee cartilage
vertebrae discs
pad like cartilage of the knee
menisci
functions of bone
support movement protection mineral storage blood cell formation
classifications of long bone
long bones
short bones
flat bones
irregular bones
long bones
functions as levers
ex. humerus
short bones
roughly cube shaped
glide motion
ex. ankle and wrist bones
flat bones
functions as protection
ex. skull, ribs, sternum
irregular bones
things fit into these irregularities
ex hips vertebrae
bone tissue types
compact
spongy
compact bone
smooth and solid in appearance
outer casings
tougher
more minerals
spongy bones
honeycomb
spaces help diffuse force
structure of long bones
diaphysis epiphysis blood vessels medullary cavity membranes
diaphysis
shaft of bone
epiphysis
expanded end area
why do bones broaden?
to relieve stress
epiphyseal line
will eventually become a line
growth plate used to elongate bone
red marrow
blood cell production
eventually becomes yellow and stops producing
articulate cartilage
cushioning
medullary cavity
contains bone marrow
membranes
used to make bones
periosteum
endosteum
periosteum
outside of bones
contains sharpeys fibers
perforating (sharpeys) fibers
more concentrated at tendon and ligament
endosteum
internal of bone
structure of short, flat, and irregular bones
sandwhich - thin outside compact layers with spongy in between
what do bone cells excrete?
extracellular matrix
responsible for maintaining and remodeling
bone cells
osteogenics
osteoblasts
osteocytes
osteoclasts
osteoblasts
bone forming
deposit bone matrix
ossification
build up bone matrix
functions of bone matrix
synthesize collagen
accumulate calcium and phosphate
appositional growth
osteoblasts of the inner periosteum add a new layer to the preexisting bone
increasing diameter
osteocytes
mature bone cells trapped in the new matrix
function of osteocytes
maintain existing matrix
osteoclasts
bone destroying cells
clast means dissolve
what is the function of osteoclasts
responsible for the breakdown and reabsorption of bone matrix, constantly occuring
secrete H+ and enzyhmes to breakdown mineralized bone matrix
calcium and phosphate freed
how are osteoclasts formed?
fusion of stem cells
structures of compact bone
osteon
circumferential lamellae
structure of osteon
lamella central canal perforating canals canliculi osteocytes
lamella
ring around osteon
central canal
blood vessels and nerves
perforating canals
connect vessels and nerves
canaliculi
the space between two osteocytes
circumferential lamellae
go around bone as whole, outside rings
used for bone widening
spongy bone
less dense, lighter
consists of trabeculae with spaces in between
trabeculae
interconnecting plates found in spongy bone
chemical composition of bone matrix
flexibility (collagen) + strength (minerals)
how do flat bones of the skull grow?
intramembranous
grow from inside point outward
ex. fontanels
intramembranous
calcification centers develop within a membrane
what happens to fontanels?
turn into sutures after growth stops
model for long bone growth
bones shape is formed by hyaline cartillage
osteocytes replace chondrocytes and cartillage bone
active growth areas of cartillage remain in the epiphyses forming growth plate through adolescence
what age does epiphyseal line form?
18 yrs for female
21 yrs for male
factors affecting bone growth
nutrition
hormones
nutrition that affect bone growth
vitamin D
calcium
vitamin C
vitamin D deficiencies
rickets
osteomalacia
rickets
childhood demineralization of bone
formative deformities
osteomalacia
adult form softening of bone
calcium is dependent on what?
vitamin D absorption
vitamin C deficiencies
scurvy - lack of normal collagen synthesis
wound healing impaired, loose teeth
impacts fibrosis stage of repair
hormones that impact bone growth and remodeling
growth hormone
thyroid hormone
sex hormones
thyroid hormone does what?
increases metabolism -> increase energy -> increase repair
sex hormones do what to bone growth
testerone prolongs growth at epiphyseal plates
estrogen increases bone mass
“a healthy bone is…”
a stressed bone
clasifications of fractures
closed/ simple (single)
open / compound (multiple)
how are bone fractures treated?
reduction (realignment of the bone)
types of fractures
comminuted compression depressed impacted spiral greenstick
steps of bone repair
hematoma is formed
break is splintered by fibrocartillage
fibrocartillage callus is replaced by bony callus
bony callus is remodeled
effects of aging
highest bone mass is around 30
bones become more brittle
osteoporosis
why do bones become brittle as we age?
less flexible collagen is synthesized
less mineral matrix is deposited as osteoblasts slow down
women are susceptiple to demineralization after menopause
osteoporosis
results from the rate of absorption beaing faster than the rate of new bone formation
what does the female hormone estrogen do?
lessen osteoclast activity
as estrogen levels drop after menopause, some women experience rapid demineralization
women can lose up to 50% bone mass
causes of osteoporosis
reduction of dietary calcium
overproduction of parathyroid hormone
overactive osteoclasts
what is the purpose of the parathyroid hormone
causes calcium to move from bone to blood
treatments of osteoporosis
vit D and calcium
drugs aimed at slowing down osteoclasts
fosomax, HRT (hormone replacement therapy)
calcium homeostasis in the blood
very tightly controlled by the body within 10% of normal
increase by 30% will cause nervous and muscle cells to become unresponsive
decrease by 35% will cause overexcited neurons and convulsions
