Skeletal system notes from class Flashcards
what are the 6 fxns of the skeletal system
support and shape
movement
protection
storage of minerals
storage of lipids
blood cell production
where does movement occur
at joints
what bones are involved in protection
cranium of brain
ribcage of internal organs
how much of bone is inorganic salts
about 2/3
how much of the bodys Ca++ is in bone
about 99 %
what si phosphate needed for
energy
component of nucleic acid
modulating protein activity
what is calcium needed for
keeping bones hard
nervous impulses
muscle contraction
clotting
where are lipids stored
in the shaft of the bone, whcih is hollow
what is the shaft of a bone filled with
yellow bone marrow/fat
what is hemopoiesis
the formation of all red blood cells, and white blood cells, and platelets
where is red bone marrow located
at the epiphyses of long bones
body of vertebrae
where is yellow bone marrow loacted
diaphysis/ shaft of bones
what does calcitonin do
puts calcium in the bones
what does parathyroid hormone do
obtain calcium by degrading bone
how may named bones are there
206
what are the 3 cartilages
hyaline
fibrocartilage
elastic cartilage
where is hyaline cartilage found
nose
ends of bones
ribs
where is fibrocartilage found
intervertebral disc
pubic symphysis
where is elastic cartilage found
auricle
epigoitis (flap of pharynx)
what cartilage is tougher
fibrocartilage
what cartilage has more collagen fibers…. which has more elastic ?…. which is the most common?
fibrocartilage has more collagen
elastic cartilagee has more elastic fibers
hyaline cartilage is the most common form
what are articular discs
flat bands of fibrocartilage
what do tendons do
connect bone to muscle
stability/movement
what do ligaments do
connect bone to bone
stability
what are the 3 main parts of the axial skeleton
skull, vertebrae, tharacic cage
what are the 4 main parts of the appendicular skeleton
pectoral girdle, upper apendage, pelvic girdle, lower apendage
how is compact bone organized
into parallel osteons/haversian systems
how does compact bond increase strength
it is layered up and down
it can withstand compression
how are osteons arranged in spongy bone
irregularly
what are the 6 histology portions of compact bone
haversian systems
haversian canal
lamellae
osteocytes within lacunae
canaliculi
perforating/volkmanns canal
what are hvaersian canals
openings in the center of compact bone
does spongy bone have haversian canals
no
what are lamellae
layers of Ca++ salts
what are osteocytes
bone cells
what are lacunae
small gaps in bone tissue
what are canaliculi
little tunnels between lacunae
where do canaliculi open in compact bone
to the haversian canal
what is the perforating/volkmanns canal
the entrance point for blood vessels/nerves
they look horizontal
where is spongy bone found
at epiphyses between layers of compact bone
what are the 5 main histology parts of spongy bone
trabeculae
lamellae
osteocytes with lacunae
canaliculi
red bone marrow
what is trabeculae
thin plates of bone
what do canaliculi open to in spongy bone
they connect lacunae and open to outside of the trabeculae
where is red bone marrow found in spongy bone
filling the spaces
what makes each trabeculae
a single osteon
ahat are the layers of bone
periosteum
endosteum
medullary cavity
wher is periosteum
superficial
where is endosteum
deeper than periosteum
what are the layers of periosteum
fibrous later - dense, irreg Ct,
cellular layer- osteogenic cells and osteoclasts
what is the fibrous layer of periosteum continuous with
tendon
what do osteogenic cells do
build new bone
what layers are in endosteum
cellular layer only
osteogenic and osteoclast cells
what is the medullary cavity
the holllowed area found in the middle of the diaphysis
what does the medullary cavity store
lipids/fats
what are the 4 bone cell types
osteoprogenitor cells
osteoblasts
osteocytes
osteoclasts
how much of bone tissue is made up of bone cells
about 2 %
where do osteoprogenitor cells form from
mesoderm
what do osteoblasts do
osteogenesis
what are osteocytes
mature bone cells
involved in bone maintenacne
what do osteoclasts do
break down bone
what are osteoclasts derived from
luekocytes
what does bone buidling
osteoblasts
what does bone recycling
osteoclasts
what must blanace for there to be homeostasis
bone building must balance bone recycling
when does osteoporosis occur
when there is high bone recycling and low bone building
when does fibrodysplasia obsificans progressive occur
whene there is and icnrease in bone building and a decrease in bone recycling
what does the nuclues look like in osteoblasts
is prominant
what is needed for protein synthesis in osteoblasts
rough er and mitochondira
what are the two ways osteogenesis occurs
collagen synthesis/secretion
and calcification
what does calcification form
ca ++ salt crystals on the collagen
makes hydroxyapatite
this is hard like glass
what cells do collagen synthesis and calcification
osteoblasts
what are immature bone cells
osteoblasts
what does the nucleus look like in osteocytes
prominant like osteoblasts
what does they cytoplasm look like in osteocytes
a thin run
where are osteoclasts located
within the cellular layer of periosteum/endosteum
what are osteoclasts derived from
monocytes
are osteoclasts large or small? how many nuclei?
large, multinucleated (5-200)
how are osteoclasts made
due to fusion of multiple cellss
what are the 4 areas in osteoclasts
resorptive surface
ruffled border
clear zone
vesicular region
what do osteoclasts incerase for digestion
Surface area
what does the resorptive surface look like in osteoclasts
it is the bone itself
has a frayed edge/border
(its partially digested)
what does the ruffled border look like
branched, fingerlike extentions that poke into bone surface
where is the clear zone
on either side of ruffled border
what is the clear zone devoid of
organelles
what is the vesicular region
where vessicles are present
it contains enzymes and acids
what are the 2 steps of bone digestion
- focal decalcification
- extracellular digestion
what happens at focal decalicifaciton
removal of ca++ salts
decresing pH be secreting acid
bone becomes softer there
what happens during extracellular digestion
enzymes are secreted
proteins are digested
what are the 2 different types of bone formation
osteogenesis and ossification
what is osteogenesis
formation of bone
what is ossification
process of replacing another tissue with bone
what are the 2 forms of ossification
intramembranous ossification and
endochondral ossification
what happens during intramembranous ossification …
replacing fibrous membrane tissue with bone
what ossification makes flat bones
intramembranous ossification
what ossification makes seamoid bones
intramembranous ossification
what ossification makes long bones
endochondral ossification
what happens during endochondral ossification
hyaline cartilage model is replaced with bone
what are the 6 steps of intramembranous ossification
differentiation of mesenchymal cells
secretion of osteoid tissue
deposition of hydroxyapatite
formation of spicules
formation of trabeculae
bone remodeling
where does differentiation of emsenchymal cells occur
within the membranw
if differenetiation of mesenchymal cells occurs near capillaries with an appropriate stimulus, then what happens
the mesenchymal cells can differentiate into osteoblasts
what is osteoid tissue
prebone - primarily collagen
where is osteoid tissue secreted
around cells
what does the increase concentration of salt loccatlly do
to point deposition
what are spicules
needle like projections from bone tissue that are lined with endasteum
what do osteoblast lay down during the formation of spicules of initramembranous ossification
lay down bone to form lamelae
what are trabeculae
spicules thicker and connect
what are fontanels
membranous areas on fetal skull
what are soft spots on fetal skull
fibrous meembrane…
fontanesls
what are the 2 functions of fontanels
flexibility
and
to accomodate rapid brain growth
what does the flexibility of fontanels allow for
modling/compression of skull bones to facilitate birth
what are the 4 fontanels
anterior
occipital
sphenoidal
mastoid
what are the steps of endochondral ossification…. 11
hyaline cartilage model
cartilage cells hypertrophy
calcification of cartilage
chondrocytes die/cartilage begins to erode
blood vessel grow around model
formation of bony color
cartilage continues to erode/die
invation of periosteal bud
primary ossification center
remodleing creates marrow cavity
secondary ossification centers
what dont chondroblasts have
no capillaries
what happens during carilage cells hypertrophy
get bigger
What happens during calcification of cartilage
ca++ deposits around bigger cells
what is perichondrium converted to
periosteum
with capillaries nearby, what can osteoprogenitor cells do
differentiate into osteoblasts
what type of growth involves adding layers of lamellae around pieces of calcified cartilage
appositional growth
when capillaries grow into carilage model, what do they deliver
osteoprogenitor cells inside (also osteoclasts)
what is the secondary ossification center. when?
after birth
where does the secondary ossification center form
in the epiphysis
where is the epiphysis
ends of bonds
what is an epiphyseal plate
longitudinal growth of bone
what does carilage allow for
grown longitudinally
when carilage is completely replaced by bone what happens
no longer able to grow
whare are the 5 areas of an epiphyseal plate
resting zone
proliferating zone
maturing zone
calcifying zone
bone replacement zone
what happens at the epiphyseal plate resting zone
not contributing to bone growth
anchor epiphysis to epiphyseal plate
what happens at the proliferating zone
cell division is occuring
interstitial growth
mitotic figures present
formation of longitudinal columns of cells
what stimulates the proliferating zone
growth hormone
what is the maturing zone
hypertrophy of cell
what is the calcifying zone /what happens there
depositing Ca++
diffusion
promotes dying
cell erodes away
what happens at the bone replacement zone
blood vessels grow in from
what does the diaphysis do at the bone replacement one
carry away debris, and carry in osteoprogenitor cells
what do osteoblasts do at the bone replacement zone
lay down bone
what type of growht occurs at an epiphyseal plate
appositional growth
where does interstitial growth occur
in the proliferating zone (cartilage)
what growth only occurs at bone
appositional growth
what are the steps of bone growth and remodeling
destruction
formation
some bones more active than others
destruction of bone by what cells
osteoclasts
how can one control bone growth and remodeling
nutrition
hormones
mechanical stress
nutrition types
vitamins and minerals
what vitamins can help bone growth
C
D
K
what minerals can help bone growth
F
Mn
Ca
Ph
Mg
what does vitamin c help with
collagen synthesis
what does vitamin d help with
calcium absoption at gut
what does vitamin k help with
calcium deposits increase bone density
what hormones help bone growth
calcitonin/parathyroid hormones
growth hormones
sex hormones (testosterone and estro0gen)
what do mechanical stress’s do
stinulates bone growth
what are the steps of bone repair following fracture
- blood clot (hematoma)
- callus formation (dense CT/cartilage…. forms bridge)
- callus ossification (bone replacement of calleus)
- bone remodleing
