Skeletal basics Flashcards
ectoderm forms
neural crest
mesoderm forms
connective tissue, most bones
axial skeleton
vertebral column (& notochord), ribs,
sternum, branchial skeleton, skull
appendicular skeleton
limbs and girdles
joint aka articulations
do what?
located where?
how are they classified?
hold bones together
and/or allow for body movement
– where bones meets bone
– classified by structure and function
functional categories of joints
Synarthrosis, amphiarthrosis, diarthrosis
Synarthrosis
immovable
amphiarthrosis
slightly movable
diarthrosis
freely movable
what connective tissue makes up development
mesenchyme
what connective tissue makes up cartilaginous skeleton/calcification
hyaline
Cartilage what is it
connective tissue
what is function of cartilage
support and locomotion
origin of cartilage
mesoderm and neural crest origin
what cells produce cartilage
chondrocytes
matrix of cartilage
ground substance (contains chondroitin sulfate) and fibers
growth of cartilage
Appositional and interstitial growth
does cartilage have veins
no
perichondrium of cartilage
fibrous membrane with inner cellular layer, surrounds
cartilage
types of cartilage and describe
Hyaline– flexible and elastic, ribs ends of long bones
– Calcified hyaline – hard and brittle, skulls of some sharks
– Fibrocartilage – junction of ligaments and bones, intervertebral dsics
– Elastic– contains elastic fibers, springs back
recognize hyaline cartilage
recognize fibrocartilage
recognize elastic cartilage
what is bone
connective tissue
what is bone function
support
where bone come from
mesodermal neural crest
what makes bones
– Osteoblast produce bone matrix, become osteocytes in lacunae
what makes up bone
– Matrix contains phosphate and calcium salts (hydroxyapatite)
bone growth
appositional
is bone vascular
yes
how does bone change
remodeled by osteoclasts
types of bone
Dermal (membrane/intramembranous) vs Endochondral
– Compact vs Spongy
– Woven vs Lamellar (Haversian systems in mammals)
Does dermal bone have a cartilage precursor
no
where does the dermal bone develops
embryonic mesenchyme/dermis
types of dermal bone
Scales (see previous handouts)
– Skull (in part)
– Osteoderms
– Gastralia
– Plastron of turtles (belly)
– Dermal armor
what is gastralia
dermal bones found in the ventral (belly) body wall of some reptiles, like crocodiles and the tuatara, and in many prehistoric tetrapods, providing support for the abdomen and attachment sites for abdominal muscles.
The gastralia, composed of dermal bone, expands to form the ___ of turtles
plastron
Ribs and vertebrae, composed of endochondral bone, expand to form the ___ of turtles
carapace (the hard upper shell of a turtle)
In humans 8th week of fetal
development, many ___
centers within the ___,
meet at birth = simple ___
ossification, mesenchyme, bony
plates
Flat bones of cranial vault,
irregular bones of face, clavicle
and who has them
osteoderms, gastralia, armadillo armor
Mixed dermal/endochondral
bones (dermal bone formation)
what bones in the skull?
occipital, temporal,
sphenoid
Formation of bone step 1
an ossification center appears in the fibrous connective tissue membrane
- centrally located mesenchymal cells cluster and differentiate in osteoblasts, forming and ossification center
Formation of bone step 2
Bone matrix (osteoid) is secreted within the fibrous membrane
* Osteoblasts begin to secrete osteoid, which is mineralized
within a few days.
* Trapped osteoblasts become osteocytes
Bone formation step 3
Woven bone and periosteum form.
* Accumulating osteoid is laid down between embryonic blood
vessels, which form a random network. The result is a network
(instead of lamellae) of trabeculae.
* Vascularized mesenchyme condenses on the external face of
the woven bone and becomes the periosteum.
Bone formation step 4
Bone collar of compact bone forms and
red marrow appears.
* Trabeculae just deep to the periosteum thicken, forming a
woven bone collar that is later replaced with mature lamellar
bone.
* Spongy bone (diploë), consisting of distinct trabeculae, persists
internally and its vascular tissue becomes red marrow.
compact vs spongey bone and histology
does endochondral bone have a cartilage precursor
yes
where do you find endochondral bone
– Most bones in bony skeletons
what is epiphyseal plate
cartilage
Where is the epiphysis
top/bottom of the bone
where is the metaphysis
neck of the bone
where is the diaphysis
shaft of bone
steps to form endochondral bone
1) proliferation of cells,
2) condensation of cells,
3) hypertrophy, bone collar and vascularization
4) growth axes and bone marrow compartment
5) maturation of ossification centers
6) adult bone is formed
bone remodeling: epiphysis enlarges by
growth of epiphyseal cartilage
If aligned properly, bone will
heal itself, has ___ form
fibrocartilage
intermediate
which types of bone does lamellar bone occur in
Immature vs. Mature (Lamellar) Bone
where does immature bone form
before birth + found in jaw of adults, in dental alveoli
when does mature bone form
not formed until after birth
describe non lamellar bone in a young alligator
woven bone
Fast growing,
Less ordered,
Irregular collagen
placement
describe lamellar bone in a turtle
Regular placement
of collagen, slower
growing
Haversian bone
Specialized type of
Lamellar Bone
some fish have
acellular bone
Formation of osteons of
Haversian bone requires
___ by ___
remodeling, osteoclast
and osteoblasts
formation of osteons
Osteoclast make tunnel, osteoblast follow behind adding the lamellar bone
synarthrosis
fused joint, bones meet at suture
synostosis
bone
synchondrosis
cartilage
syndesmosis
fibrous connective tissue, most sutures
ankylosis
fusion of dentaries
gomphosis
tooth socket
diarthrosis
moveable joint
enarthrosis
ball and socket joint
ginglymi
hinge joint ex: knuckle
rotataria
pivotal joint ex bird skull and atlas
arthrodia
gliding joint (intermetacarpel joints of wrist)
fibrous joint
what is it
does it have a point cavity
synarthrosis or amphiarthrosis?
ex:
Bones connected by dense regular connective tissue, no joint cavity. Functionally can be synarthrosis or amphiarthrosis.
ex: gomphosis joint, suture, sydesmosis
cartilaginous joint
what is it
does it have a point cavity
synarthrosis or amphiarthrosis?
ex:
Bones connected by cartilage, no joint cavity.
Functionally can be synarthrosis or amphiarthrosis.
synchondroses, hyaline cartilage, symphesis, fibrocartilaginous intervertebral disc
synovial joint: Bones covered in ___
cartilage, but separated by a ___
filled cavity; enclosed in an
___ capsule lined with the
___ membrane.
articular, fluid, articular, synovial
synovial joint: type?
diarthroses
classes of synovial joint
plane
joint, hinge joint, pivot joint,
condylar joint, saddle joint, and
ball and socket joint
types of synovial joint axial
Are multi-
, uni-, bi-, or nonaxial
Which came first, cartilage or bone?: The bulk of the developing skeleton in extant vertebrate ___ is ___ that is later
ossified (endochondral borne formation). Embryos tend to be evolutionarily/developmentally
conservative – implies ___ formed before ___ bone
embryos, cartilage, cartilage, endochondral
Which came first, dermal or endochondral bone?: Ostracaderms have ___ bone in cosmoid scales, with evidence of ___ in some – type of cartilage unknown, notochord was main support
– Placoderms have ___ = ___
– ___ bone appeared before ___ bone in the fossil record.
dermal, non-mineralized
vertebral elements,
ossified neural and hemal arches, endochondral bone
Dermal, endochondral
Which came first * Dermal Bone vs Cartilage???: Earliest chordate endoskeletons were ___, as found in the
pharyngeal region of amphioxus. (Cyclostome cartilage is ___)
– Later vertebrates produce ___, the main fiber found ___,
as seen in sharks and other extant vertebrates.
acellular non-mineralized cartilage, cellular, non-collagen-based
type II collagen, hyaline cartilage (cellular)
Likely order of appearance of bone =
acellular? non-collagen based? cartilage -> dermal bone -> cellular
collagen based cartilage? -> endochondral bone
Cartilage may have
evolved independently
in ____
Agnathans and
Gnathostomes
what forms the chondrocranium
mesoderm, neural crest
