Bone Histology Flashcards
what is the matrix of cartilage composed of?
type II collagen
name the two matrices of collagen
territorial
interterritorial
describe territorial cartilage matrix
adjacent to chondrocytes…poor in collagen
where is interterritorial collagen matrix located?
further from chondrocytes and has more collagen
which of interterritorial and territorial matrices stains dark?
territorial
what are chondrocytes embedded in?
lacunae within the matrix
where are most chondroblasts located?
in the perichondrium
what is the perichondrium? what is it made of?
layer of dense irregular connective tissue surrounding hyaline and elastic cartilage
what type of cartilage doesnt have perichondrium?
fibrocartilage
what are the two types of cartilage growth?
interstitial and appositional
what is interstitial cartilage growth?
existig chondrocytes make more chondrocytes
where is a common place for interstitial cartilage growth to occur?
epiphyseal plates of bone
what is appositional growth of cartilage?
chndrogenic cells become chondroblast then chondroblasts become chondrocytes
where does appositional growth of cartilage occur?
in perichondrium
hyaline cartilage has what type of collagen?
type II
elastin cartilage has what type of collagen?
type II
fibrocartilage has what type of collagen?
type I
which two types of cartilage have perichondrium?
hyaline and elastin
name three common places for elastin cartilae
ear, epiglottis, laryngeal cartilages
where is hyaline cartilage found?
articular ends of bones, respiratory system
where is fibrocartilage found?
IV discs, insertion of tendons, meniscus
name the two matrices of bone
inorganic
organic
the inorganic matrix of bone mainly has what in it?
calcified tissue
the organic matrix of bone has what in it?
type I collagen
what cell differentiates into osteoblasts?
osteoprogenitor cells
what shape are osteoblast when active? what about inactive?
cuboidal when active and flat when inactive
what do osteoblasts secrete?
osteiod
what is osteiod?
uncalcified bone matrix…type 1 collagen
what is an osteocyte?
when osteoblast gets entrapped in its own matrix
how do osteocytes communicate?
through gap junctions via their caniliculi
what is osteoclasts role? where do they reside?
break down bone…reside in Howships lacunae
what is a Howship lacunae?
depressions representing bone resorption
what color is cytoplasm of osteoclasts?
very pink
PTH stimulates bone growth or resorption?
resorption
name the four zones of an osteoclast
basal zone
ruffled border
clear zone
vesicular zone
what happens at the ruffled border?
this is the active site of resorption
what is the clear zone of a osteoclast used for?
actin filaments to maintain contact with bone that is being resorbed
what are the three steps of bone resorption?
acid release from osteoclasts
different enzymes degrade bone
osteoclasts resorb everything
what is the periosteum?
outer layer of bone that is not calcified and makes articulations
what are sharpey fibers in the periosteum?
they are the type I collagen fibers that connect the periosteum to the underlying bone
what is the endosteum?
thin inner connective tissue layer that lines the bone marrow cavity
what does the endosteum provide to the marrow cavity?
osteoprogenitor cells and osteoblasts
what is spongy bone composed of?
interconnected trabeculae which surround cavities filled with bone marrow
what are the trabeculae of spongy bone made of?
osteocytes and osteoblasts on each surface
what is spongy bone surrounded by?
compact bone
what does primary bone mainly have in it?
many osteocytes with irregulary arranges type I collagen bundles…and low mineral content
what is primary bone replaced by?
secondary bone
what is secondary bone made of?
calcified matrix arranged in regular lamellae with osteocytes in lacunae
what are the long cylindrical structures that run parallel to bone axis in bone?
haversian systems or canals
what connects different haversian canals?
Volkmann channels
what surrounds haversian canals?
lamellae
what are interstitial lamellae?
irregularly shaped lamellae that are between haversian canals…remnants of old bone
what are the five zones of cartilage at epiphyseal plates?
zone of reserve proliferation maturation and cell hypertrophy calcification ossification
what happens in zone of reserve?
regular cartilage is there
what happens in zone of proliferation? how does it look?
rapid mitotic division of chondrocytes..stacked on each other
what happens in zone of maturation and hypertrophy?
cells grow in size and get ready to die
what happens in zone of calcification?
chondrocytes die and get calcified
what happens in zone of ossification?
osteoblasts start dropping some bone matrix around calcified cartilage
what movement occurs in synarthroses joints?
NONE
what movement occurs in diarthroses joints? what is another name?
maximum movement….synovial joints
name two joint types
synarthroses and diarthroses
what are the two layers of an articular cavity in a joint?
fibrous capsule
internal synovial capsule
what are the two cell types of internal synovial capsule in joint?
Type A and B
what do type A synovial capsule joint cells do?
phagocytic
what do type B synovial capsule joint cells do?
secrete synovial fluid and serve as fibroblasts