Cartilage Flashcards
o smooth-surfaced and resilient, providing a shock-absorbing and sliding area for joints and facilitates bone movements
o Essential for the development and prenatal and postnatal growth of long bones
o flexible and avascular
o nutrient is acquired through diffusion from adjacent tissue or from capillaries of the neighboring tissue
CARTILAGE
CARTILAGE Consists of:
Chondrocytes
Extensive ECM
Principal macromolecules present in all types of cartilage ECM:
o Collagen
o hyaluronic acid
o proteoglycans
o small amounts of several glycoproteins
ECM is synthesize and secreted by
chondrocytes
chondrocytes are located in matrix cavities called
LACUNAE
provides nutrients to the cartilage
PERICHONDRIUM
Firm gel-like consistency of cartilage depends on:
electrostatic bonds
binding of water
the most common form of cartilage
HYALINE CARTILAGE,
HYALINE CARTILAGE principal collagen type
type II collagen
more pliable and distensible type of cartilage
ELASTIC CARTILAGE
o ELASTIC CARTILAGE,
in addition to collagen type II, possess abundance of
elastic fibers
present in regions of the body subjected to pulling forces
FIBROCARTILAGE
FIBROCARTILAGE characterized by a matrix containing a dense network of
coarse type I collagen fibers
Hyaline cartilage examples of localization
cartilages in nose
articular cartilage of a joint
costal cartilage
meniscus (padlike cartilage in knee joint)
Respiratory tract cartilages in the lungs, trachea and larynx
Fibrocartilage examples of localization
cartilage of intervertebral disc
pubic symphysis
Elastic cartilage examples of localization
Epiglottis
cartilage in external ear
is a sheath of dense connective tissue that surrounds cartilage in most places
perichondrium
All three forms of cartilage are
avascular
harbors the vascular supply for the avascular cartilage and also contains nerves and lymphatic vessels
perichondrium
covers the surfaces of the bones in movable joints
ARTICULAR CARTILAGE
devoid of perichondrium
ARTICULAR CARTILAGE
ARTICULAR CARTILAGE is sustained by the diffusion of oxygen and nutrients from the
synovial fluid
o precursors of the bone that develops through endochondral ossification
o bluish white and usually translucent
o glassy translucent appearance
HYALINE CARTILAGE
HYALINE CARTILAGE Located in:
o articular surfaces of the movable joints
o walls of larger respiratory passages
o ventral ends of ribs
o epiphyseal plate
In routine histology preparations, the collagen is indiscernible for two reasons:
- collagen is in the form of fibrils which have submicroscopic dimensions
- refractive index of the fibrils is almost the same as that of the surrounding substances
hyaline cartilage o contains primarily
type II collagen
help anchor chondrocytes in the matrix
multiadhesive glycoprotein-
what are the multiadhesive glycoproteins
anchorin II, fibronectin, tenascin
proteoglycans contain:
- CHONDROITIN 4-SULFATE
- CHONDROITIN 6-SULFATE
- KERATAN SULFATE
proteoglycans resemble
bottle brushes
parts of proteoglycans
stem
bristles
bristles of proteoglycans are made of
radiating GAG chains
stem of proteoglycans are made of
protein core
proteoglycan monomer:
AGRECAN
many proteoglycans attached to hyaluronic acid
proteoglycan aggregates
macromolecule that binds specifically to GAGs, collagen type II and integrins, mediating the adherence of chondrocytes to the ECM
CHONDRONECTIN-
cells of cartilage
Chondrocytes
chondrocytes respire under
low oxygen tension
Synthesis of sulfated GAGs is accelerated by
GROWTH HORMONE, THYROXINE, AND TESTOSTERONE
Synthesis of sulfated GAGs is slowed by
by CORTISONE, HYDROCORTISONE, AND ESTRADIOL
Cartilage growth depends mainly on the pituitary- derived growth hormone:
SOMATOTROPIN
SOMATOTROPIN
- promotes the endocrine release in the liver of
insulin-like growth factor-1 (IGF-1), somatomedin
are round chondrocytes and appear in groups of up to eight cells originating from mitotic divisions of a single
ISOGENOUS AGGREGATES
layer of dense connective tissue that covers all hyaline cartilage except the articular cartilage of joints
Perichondrium
Perichondrium consists largely of __________ s and contains numerous _______—
collagen type I fiber
fibroblasts
ELASTIC CARTILAGE color
yellowish
ELASTIC CARTILAGE Contains
collagen type II fibrils
ECM of what cartilage does not calcify?
elastic cartilage
ELASTIC CARTILAGE are found in?
o auricle of the ear
o walls of the external auditory canals
o auditory (eustachian) tubes
o epiglottis
o cuneiform cartilage in the larynx
FIBROCARTILAGE components:
combination of hyalin cartilage + dense connective tissue
FIBROCARTILAGE chondrocyte formation
singly or in isogenous aggregates,
usually arranged axially,
in long rows separated by coarse collagen type I fibers
Fibrocartilage are Found in:
o intervertebral disks
o In attachments of certain ligaments
o in the pubic symphysis
o Intervertebral disks are composed of fibrocartilage
o two major histological components of each disk:
PERIPHERAL ANNULUS FIBROSUS
CENTRAL NUCLEUS PULPOSUS
histological components of Intervertebral disks that is rich in bundles of type I collagen
PERIPHERAL ANNULUS FIBROSUS
histological components of Intervertebral disks that has a gel-like matrix rich in hyaluronic acid
CENTRAL NUCLEUS PULPOSUS
presence of perichondrium in HC, EC, and FC
HC- YES (except for articular cartilage and epiphyseal plate)
EC- YES
FC- NO
calcification of HC, EC, and FC
HC- YES
EC- NO
FC- YES
main cell type in HC, EC, and FC
HC- CHONDROBLASTS AND CHONDROCYTES
EC- CHONDROBLASTS AND CHONDROCYTES
FC- CHONDROCYTES AND FIBROBLASTS
characteristic features of ECM in HC, EC, and FC
HC- TYPE II COLLAGEN AND FIBRILS AND AGGRECAN
EC- TYPE II COLLAGEN, FIBRILS, ELASTIC FIBERS, AGGRECAN
FC- TYPE I AND II COLLAGEN FIBERS AND VERSICAN
Hyaline cartilage calcification example
endochondral bone formation, during aging process
Fibrocartilage calcification example
calcification of fibrocartilaginous calus during bone repair
the most important proteoglycan
aggrecan
a proteoglycan secreted by fibroblasts
versican
All cartilage derives from the embryonic mesenchyme in the process of
chondrogenesis
resulting from the mitotic division of preexisting chondrocytes
- occurs in the epiphyseal plates of long bones and within articular cartilage
- important in increasing the length of long bone
INTERSTITIAL GROWTH
resulting from the differentiation of perichondrial cells
- more important postnatally
- During postnatal (childbirth), the appositional growth is more important than the interstitial growth.
APPOSITIONAL GROWTH
