DAT bio Chapter 11.6 and 11.7 Skeleton Flashcards
Many
invertebrates and all arthropods possess____
exoskeleton (external skeleton)
Vertebrates contain an
endoskeleton (on the inside)
endoskeleton can be divided into two parts. what are they
axial skeleton (core bones like skull, and rib cage) and the appendicular skeleton (appendages). if the endo skeleton were a tree, the axial skeleton would be the tree trunk and the appendicular skeleton would be all the branches coming off of it.
types of long bones
long bones short bones flat bones sesamoid bones irregular bones
long bone is made out of
cortical bone (compact cancellous bone (spongy)
important features of long bone include
epiphysis, diaphysis, medullary cavity,
metaphysis, and epiphyseal plate.
Epiphysis - is
end of a long bone that forms
joints with other bones and contains red
bone marrow for hematopoiesis (blood
cell synthesis).
Diaphysis
long hollow shaft in center of
bone.
Medullary cavity
located within the
diaphysis and contains red and yellow
bone marrow (area of fat storage).
Metaphysis
similar to epiphyses and
found between the medullary cavity and
epiphyseal plates.
Epiphyseal plate is
“growth plate” located between epiphysis and metaphysis. Made out of hyaline cartilage and works to lengthen the diaphysis through growth and ossification.
short bone provide what
as wide as they are long and
mainly provide support (eg. parts of the
wrist).
Flat bones -
mainly provide protection (eg.
skull).
Sesamoid bones
found within tendons to
help muscles pull (eg. kneecap).
Irregular bones
- irregularly shaped (eg.
pelvis) .
Cortical (compact) bone
dense outer layer of bone that
supports the weight of our bodies. It is composed
of many microstructures:
microstructures of cortical bone
osteons haversian canals lamella lacunae canaliculi volkmanns canals
osteons
- cortical bone’s functional unit,
composed of tiny multi-layered cylinders.
Also known as haversian systems because
they contain a haversian canal in their center.
Haversian canals
‘tubes’ that contain blood
vessels for nutrient supply.
lamellae
layers of the osteon
lacunae
small spaces between lamellae that
hold bone cells and interconnect through
canaliculi.
canaliculi
small channels that connect lacunae and the haversian canal
volksmanns canal
connect Haversian canals
to the periosteum, which provides nutrients.
what is cancellous bone
the spongy inner layer of bone
that soaks up red bone marrow via a web of
trabeculae (connective tissue that supports
cancellous bone).
what is bone remodeling
process of going back and
forth between the processes of ossification (bone
formation) and resorption (bone loss).
Types of cells involved in bone remodeling:
Osteoprogenitors
Osteoblasts
Osteocytes -
Osteoclasts
Osteoprogenitors
- immature precursor cells
that differentiate into osteoblasts.
Osteoblasts
build bone by secreting
proteins and utilizing blood calcium. They
mature into osteocytes after getting trapped
inside the bone matrix they create.
Osteocytes
live in lacunae in osteons to
maintain bone.
Osteoclasts
eat and resorb bone, bringing
calcium back into the blood. Derived from
monocytes.
Mechanisms involved in bone remodeling
parathyroid hormone
vitamid d
calcitonin
Mechanisms involved in bone remodeling S1
parathyroid hormone
increases blood
calcium levels by stimulating osteoclasts and
depressing osteoblasts. Secreted by the
parathyroid gland.
Mechanisms involved in bone remodeling S2
vitrami d
increases blood calcium levels by
raising intestinal calcium absorption. Activated
by parathyroid hormone, but provides
negative feedback on PTH production.
Mechanisms involved in bone remodeling S3
calcitonin
decreases blood calcium levels by
depressing osteoclasts, allowing osteoblasts to
build bone without competition. Secreted by
the thyroid gland.
what is osteoid
organic component of bone
containing many proteins such as collagen (gives
bone tensile strength).
what is Hydroxyapatite
inorganic mineral
component of bone that gives the bone density
and strength.
two types of embryonic ossification
intramembranous and endochondral ossification
Intramembranous ossification
bone is
created directly within fibrous membranes,
mainly for flat bones. Osteoblasts start by
secreting osteoid, which hardens and houses
osteocytes. Eventually, cortical bone is
created.
Endochondral ossification
bone is created
indirectly through a cartilage model, mainly
for long bones. The cartilage model calcifies
during fetal development, creating
ossification centers that help form the
features of long bones.
what fibers make up the fibrous connectice tissue?
tendons
ligaments
periosteum
endosteum
tendons connect what
muscle to bone.
Ligaments connect what
bone to bone
periosteum is what
- membrane that covers
cortical bone with an outer fibrous layer
(vascularized) and an inner/cambium
layer (collagen for attachment to cortical
bone)
Endosteum is what
membrane located between
cortical and cancellous bone.
Cartilage is ______ (lacks blood vessels)
and is not innervated (as opposed to bone
which is highly vascular and innervated).
avascular
what builds cartilage
chondroblasts