lecture 2 skeleton Flashcards
some functions of skeleton
provide framework
allows motion through joints
provides muscle leverage
protects organs
axial skeleton
skull
vertebra
ribs
appendicular skeleton
scapular and arms
pelvis and legs
skeletal tissues are derived from
connective tissue
skeletal tissue
some are non-mineralized (lack hydroxyapatite)
- notochord
- cartilage
Some are mineralized
(have hydroxyapatite)
-calcified cartilage
-bone
mineral that allows for mineralization
hydroxyapatite
describe notochord
non mineralized (no hydroxyapatite)
source of developmental signaling
in vertebrates, becomes nucleus pulposus in each intervetebral disc
what does notochord turn into in vertebrate adults
nucleus pulposus of the intervertebral disc
Cartilage
non mineralized (lack hydroxyapatite)
composed of
- gel matrix (chondromucoprotein and water)
- collagen or elastic fibers
- chondrocytes (cartilage cells)
no blood supply or innervation
flexible
easy to injure, difficult to reapir
growth tissue in fetus and juvenile
in adults- ears, nose, larynx and joints
cartilage cells
chondrocytes
gel matrix of cartilage is made of
chondromucoproteins and water
where is cartilage in adults
ears, nose, larynx and joints
Calcified Cartilage
mineralized (hydroxyapetite in gel matrix)
-tissue hard, brittle and opaque
unorganized microstructure
-minerals added randomly between cartilage cells
stronger than cartilage
transitional tissue
where is calcified cartilage found
shark vertebrae
horse larynx
deepest articular cartilage
calcified cartilage is stronger than ___ but harder to heal because ___
cartilage
hydroxyapetite blocks diffusion of things needed to heal area
Bone is made of
organic and inorganic components
organic components of bone
osteroids
- type 2 collagen and bone matrix proteins
- hormone osteocalcin
- 20-25% bone weight
cells -some from mesenchyme =osteocytes =osteoblasts -some from hematopoietic tissue -osteoclasts
type of bone cell from mesenchyme
osteocytes
osteoblasts
types of bones cells from hematopoietic tissue
osteoclasts- break down bone
type of cells that break down bone
osteoclasts
type of cells that create bone
osteoblasts
Osteoblasts are specialized mesenchymal cells that synthesize bone matrix and coordinate the mineralization of the skeleton
inorganic components of bone
hydroxyapatite
- how bones mineralize
- 60-70% of bone weight
Water
Bone only grows at ___ and is ___ throughout life
at surface
remodeled
Bone has a nerve and blood supply that travels through ___
haversian canals
minerals that are reserved in bone
Calcium
Phosphorous
Potassium
making of blood cells in ___ inside bone core is called ___
red marrow
hematopoiesis
during growth, red marrow is ___ by fat and becomes ___
replaced
yellow marrow
What hormone does bone release
osteocalcin
what does osteocalcin do
- insulin regulation
- brain development and function
- testosterone formation and release
round layered formation of bone
osteon
layers of an osteon
lamellae
small cellular processes that connect osteocytes to each other
canaliculi
4 shapes of bones
long
short
flat
irregular
example of long bone
limb bones
humerus, radius, ulna
long bones
cylindrical
act as levers
form from 3 centers of ossification (one diaphysis, 2 epiphyses)
short bones example and define
carpal and tarsal
form from single center of ossification
Flat bones
example and define
expand in two directions
skull, scapula, pelvis
grooves
sulci
bumps
tubercles and tuberosities
shaft of bone
diaphysis
contains the growth plate
metaphysis
end of bone
epiphysis
important for stabilized joints during growth
growth plate
physis
cartilaginous
present while bone is growing
spongy bone
trabeceular
where blood is formed
medullary cavity (marrow cavity)
outer surface of bone
periosteum
descrive periosteum
- outer surface of bone
- living tissue helping build and maintain bones
- fibrous outer layer- fibers, elastin, vessels and nerves
- inner osteogenic cell layer
thin membrane lining the marrow cavity
endosteum
little holes in osteons where bone cells called ___ live
lacunea
osteocytes
network formed by osteocytes
mechanoreceptive syncytium
Bone gets ___% of total cardiac output
5-10%
large nutrient artery enters into the bone by ___ which is in the ___ of the bone
nutrient foramen
diaphysis (shaft)
smaller vessels supply the ___ and ___ of bone
metaphysis (growth plate area)
epiphysis (end of bone)
Will blood vessels cross the physis?
growth plate = physis
no blood is separate during growth, ephiphyseal artery and main nutrient artery will connect after bone is done growing
explain endochondral bone growth
will use cartilage precursor
first in diaphysis (shaft)
later in epiphyses (ends of bone)
at same time perichondrium will be replaces by periosteum on outer shaft of bone
medulla cavity(marrow cavity) will form
some examples of endochondral bone
- axial skeleton ( vertebrae, ribs)
- limbs
- ventral braincase
perichondrium to periosteum will create __ on the __ of the bone
compact bone
outer surface of the shaft of the
example of membrane/dermal bone growth
flat bones of skull
explain membrane bone growth
membrane=dermal bone growth
- no cartilage precursor
- trabeculae form directly in mesenchyme
- bone grows outward
- growth zone at edge of developing bone
- derived from neural crest cells
growth zone of membrane bone is at the ___
sutures (edge of developing bone)
what is a sesamoid
bones that form within tendons
how do sesamoids help
- prevent muscle from deforming
- improve muscle leverage
BMU
basic multicellular units
what are BMU
basic multicellular units
how bone is remodeled
hormone osteocalcin determines
- resorption by osteoclasts
- replacement by active osteoblasts
- resting- inactive osteoblasts
what type of bone cells eats bones
osteoclasts
entire skeleton is remodeled every ___ years
10
soft tissue structures that hold skeleton together
ligaments
joint capsules
menisci
bursa
Describe ligaments
- bundles of connective tissue fibers
- connect bones at joints
- permits and limits motion
bone to bone
describe joint capsules/synovial joints
found in synovial joints
- synovial fluid
- synovial membrane
- fibrous outer layer
- capsular ligaments
Describe Bursae
near joints but not part of joints
- protective cushion
- distinct from joint capsule
- between bone and soft tissue
three types of joints
synovial
fibrous
cartilaginous
describe synovial joints
most mobile joint
lubricated by synovial fluid
- flat- only slide (inbetween carpals)
- barrel/hinge- flex and extend (elbow)
- pivot joints- shaking head (neck and head)
- ball and socket- flex and extend, adduct and abduct, pivot and circumduct (shoulder)
- saddle (in between carpals)
movement along a conical surface
circumduction
Describe fibrous joints
allows limited motion - bones joined by connective tissue - no synovial fluid 3 types -suture -syndesmoses -gomphosis
describe sutures
type of fibrous joint
-connect membrane bones to each other
bones of skull
describe syndesmoses
type of fibrous joint
-connect endochdral bones to each other
horse splint and cannon bones
describe gomphosis
type of fibrous joint
connect tooth and jaw
describe cartilaginous joints
least mobile - bones are connected by cartilage two types -synchondrosis -symphysis
describe synchondrosis
type of cartilaginous joint
connected by cartilage
- growth plates
- joints between ribs and sternum or skull and hyoid
describe symphysis
type of cartilaginous joint
bones connected by connective tissue and cartilage
Bone- cartilage - CT- cartilage- Bone
pelvic, intervertebral and mandibular symphyses
bone is a ___ tissue with biologic functions ( ___ balance, ___ formation and ___ production)
bone is a living tissue with biologic functions ( mineral balance, blood formation and hormone production
