L10: Bone and Cartilage Flashcards
hyaline cartilage characteristics
most common type
perichondrium
blue-gray color
cell groups
growth patterns of hyaline cartilage
appositional
interstitial
locations of hyaline cartilage
external ear canal larynx trachea bronchi fetal long bones
elastic cartilage characteristics
presence of elastic fibers perichondrium yellow color more flexible single cells
elastic cartilage locations
auricle = outer ear
epiglottis
fibrocartilage characteristics
increased collagen bundles
no perichondrium
opaque
single cells in rows
locations of fibrocartilage
intervertebral discs
pubic symphysis
insertion of tendons/lig
closely associated with dense CT and hyaline
what is fibrocartilage also considered?
an extension of dense CT instead of a type of cartilage
compare the color/appearance of cartilage types
hyaline - translucent blue/gray
elastic - yellow due to elastic fibers
fibrocartilage - opaque due to collagen fibers
collagen fiber types in each cartilage type
hyaline and elastic – type II
fibrocartilage – type I
which cartilage types have a perichondrium?
hyaline and elastic
what is responsible for the slow healing rates of cartilage?
they are avascular
nutrients and oxygen must diffuse through the matrix to reach the cells
perichondrium structure
2 layers
1. outer fibrous layer w/ fibroblasts
- inner chondrogenic layer
inner chondrogenic layer
inner layer of perichondrium
gives rise to chondroblasts
chondrocytes produce fibers and proteoglycans
secrete chondronectin
groups of 2 - 8 chondrocytes in a lacunae
isogenous groups
result of mitotic division
cells separate as they excrete ground substance
functions of cartilage
compressible resist distortion absorb shock in joints reduce friction of joints endochondral growth bone fracture repair
types of cells
chondroblasts - cartilage forming
chondrocytes - cartilage matrix maintenance
matrix components
collagen type II - hyaline and elastic
collagen type I - fibrocartilage
ground substance - GAGs
subdivision of matrix in hyaline cartilage
territorial matrix
inter-territorial matrix
territorial matrix
surrounds each chondrocyte
high GAG > fiber content
inter-territorial matrix
surrounds territorial matrix
high fiber > GAG content
features of hyaline slides
no fibers
cells are random and can be grouped
territorial matrix
blue-gray color
features of elastic slides
like hyaline but with elastic fibers in matrix
random cells
can be grouped or single
naturally yellow but typically not yellow after staining
fibrocartilage features of slides
opaque color
ordered bundles of collagen
single rows of cells between collagen
list the types of bone tissue
woven bone
spongy/cancellous/trabecular bone
compact/lamellar bone
compact bone is arranged in a _____ system.
canalicular system
canaliculi feed into canals which feed into Volkmann then to blood vessels
what type of bone tissues present trabecular?
spongy bone
3D lattice branching of bony spicules intertwined
surround marrow spaces
concentric lamellae encircling a central blood vessel
osteon or haversian system
little lakes
lacunae
house osteocytes
_____ canal runs perpendicular to ______ canals.
Volkmann runs perpendicular to haversian canals
connect osteons to each other and bone surface/blood vessels
unlike cartilage, bone tissue is highly _____ .
vascularized
increase in bone length
endochondral growth
become osteocytes, become trapped by their own secretions
osteoblasts
break down osteoid
osteoclasts
components of bone matrix
organic component
inorganic component
osteoid
flexible organic component of bone matrix
hydroxyapatite
structural strength
inorganic component of bone matrix
35-65% of matrix
what does a cement line represent?
that this osteon has been remodeled
bone tissue of epiphysis, why is this important in long bones such as the femur?
trabecular bone
trabeculae resist shear forces
cells that control Ca and Pi concentrations in bone matrix
osteocytes
stem cells which become the bone lining cells in adults and give rise to osteoblasts
osteoprogenitor cells
osteoblasts are characterized by the presence of ?
alkaline phosphate
Vitamin D3
regulates expression of osteocalcin
vitamin D3
collagenous proteins produced by osteoblasts
collagen type I
Noncollagenous protein produced by osteoblasts
RANKL osteocalcin Osteonectin Osteopontin osteoprotegerin
high binding affinity for hydroxyapatite
osteocalcin
binds to RANKL with greater binding affinity than RANK
osteoprotegerin
osteoprotegerin binds _____ , thus inhibiting ….?
binds RANKL
inhibiting the binding of RANK
thus inhibiting the maturation of an osteoclast
osteoclasts are a specialized type of ______ .
macrophage
ARF cycle
activation —resorption — reversal — formation
bone remodeling steps
primary regulator of bone turnover?
parathyroid hormone
PTH initially stimulates?
differentiation of monocytes into osteoclasts
formation of ruffled border on osteoclasts
blocks synthesis of osteoprotegerin
low PTH levels
bone formation
high PTH levels
bone resorption
osteitis fibrosa
elevated PTH levels result in eroded bone and fibrosis of the resulting spaces
PTH binding to osteoblast stimulates?
osteoblast to produce:
M-CSF
RANKL
M-CSF
monocyte colony stimulating factor
what does M-CSF bind to ?
binds to macrophage
stimulating the cell to express RANK
RANK binds to RANKL resulting in?
coupling of the osteoblast and macrophage
allowing the macrophage to differentiate into an osteoclast
reduces bone resorption
calcitonin
maturation of a macrophage
becomes multinucleated
uncouples
now functional osteoclast
