Embed Size (px)
DESCRIPTION
Cartilage. Dr. Amam Ali Amam PhD: Periodontal Disease. Cartilage , Definition. Is a special form of connective tissue in which the firm consistency of the extra-cellular matrix allows the tissue to bear mechanical stresses. Is a semi-rigid form. Cartilage. - PowerPoint PPT Presentation
Citation preview
Dr. Amam Ali AmamPhD: Periodontal Disease
Dr. Amam Ali AmamPhD: Periodontal Disease
Cartilage
Cartilage, Definition
Is a special form of connective tissue in
which the firm consistency of the extra-
cellular matrix allows the tissue to bear
mechanical stresses.
Is a semi-rigid form.
Is a special form of connective tissue in
which the firm consistency of the extra-
cellular matrix allows the tissue to bear
mechanical stresses.
Is a semi-rigid form.
Cartilage
Cartilage is characterized by:
an extracellular matrix enriched
with glycosaminoglycans and
proteoglycans, macromolecules
that interact with collagen and
elastic fibers.
Cartilage is characterized by:
an extracellular matrix enriched
with glycosaminoglycans and
proteoglycans, macromolecules
that interact with collagen and
elastic fibers.
Cartilage, Functions
1- Bearing mechanical stresses. 1- Bearing mechanical stresses.
2- Support soft tissue. 2- Support soft tissue.
4- Developmental and growth of long
bones
before and after birth.
4- Developmental and growth of long
bones
before and after birth.
3- Shock-absorbing and sliding area
for joints and facilitates bone
movements.
(Because it is smooth surfaced and
resilient)
3- Shock-absorbing and sliding area
for joints and facilitates bone
movements.
(Because it is smooth surfaced and
resilient)
We have to study :• 1- cells• 2- fibers• 3- ground substance
We have to study :• 1- cells• 2- fibers• 3- ground substance
Cartilage is a connective tissue
2- Ground substance2- Ground substance1- Fibers1- Fibers
1- CellsCalled Chondrocytes
1- CellsCalled Chondrocytes
Cartilage consist of:
2- Extracellular matrix2- Extracellular matrix
1- Collagen.1- Collagen.
2- Elastic .2- Elastic .
1- Hyaluronic acid.1- Hyaluronic acid.
2- Proteoglycans.2- Proteoglycans.
3- Small amount ofseveral glycoproteins
3- Small amount ofseveral glycoproteins
• It is derived from chondroblast, which
resembles fibroblast
• It synthesizes and secretes the
extracellular matrix .
• It is interacted in the matrix that it’s
secretes it!
• Histological: it is seen in cavities called
lacunae.
• It is derived from chondroblast, which
resembles fibroblast
• It synthesizes and secretes the
extracellular matrix .
• It is interacted in the matrix that it’s
secretes it!
• Histological: it is seen in cavities called
lacunae.
Chondrocyte
Variations in the composition of these
matrix components produce three
types of cartilage adapted to local
biomechanical needs .
Variations in the composition of these
matrix components produce three
types of cartilage adapted to local
biomechanical needs .
3 Types of cartilage
1- Hyaline cartilage. 1- Hyaline cartilage.
2- Fibro cartilage.2- Fibro cartilage.
3- Elastic cartilage.3- Elastic cartilage.
Articular cartilage.Articular cartilage.
1- Hyaline cartilage. 1- Hyaline cartilage.
It is the most common type & the best
studied of the three forms. It is the most common type & the best
studied of the three forms.
Small aggregation of chondrocytes
embedded in an amorphous matrix of
ground substance reinforced by collagen
fibers ( II )
Small aggregation of chondrocytes
embedded in an amorphous matrix of
ground substance reinforced by collagen
fibers ( II )
1- Hyaline cartilage, cont... 1- Hyaline cartilage, cont...
Location:
1- in the articular surfaces of the
movable joints.
2- in the walls of larger respiratory
passage
(nose, larynx, trachea, bronchi).
3- the ventral ends of the ribs
Location:
1- in the articular surfaces of the
movable joints.
2- in the walls of larger respiratory
passage
(nose, larynx, trachea, bronchi).
3- the ventral ends of the ribs
40 % of the dry weigh of Hyaline Cartilage consist of : 40 % of the dry weigh of Hyaline Cartilage consist of :
1- collagen embedded in a firm
1- collagen embedded in a firm
2- hydrated gel of Proteoglycans.2- hydrated gel
of Proteoglycans.3- structural
Glycoproteins 3- structural
Glycoproteins
Hyaline cartilage
Hyaline cartilage
Cartilage matrix
Is a tissue intermediate between dense
connective tissue and hyaline cartilage.
Is a combination of dense supporting tissue
and cartilage.
Presents in regions of the body subjected to
pulling forces.
Is characterized by a matrix containing a dense
network of coarse type I collagen fibers.
It contains chondrocytes (singly or groups).
Is a tissue intermediate between dense
connective tissue and hyaline cartilage.
Is a combination of dense supporting tissue
and cartilage.
Presents in regions of the body subjected to
pulling forces.
Is characterized by a matrix containing a dense
network of coarse type I collagen fibers.
It contains chondrocytes (singly or groups).
2- Fibro cartilage.2- Fibro cartilage.
2- Fibro cartilage, cont...2- Fibro cartilage, cont...
It is found at :
- intervertebral discs.
- the symphysis pubica.
- the knee joint.
- the mandibular joint.
- the sternoclavicular Joint.
- the shoulder Joint.
- Ligaments and the connections of some
tendons of bone.
It is found at :
- intervertebral discs.
- the symphysis pubica.
- the knee joint.
- the mandibular joint.
- the sternoclavicular Joint.
- the shoulder Joint.
- Ligaments and the connections of some
tendons of bone.
Fibrocartilage
3- Elastic cartilage.3- Elastic cartilage.
Elastic Cartilage, characterized by its
great pliability, contains significant
amounts of the protein elastin in the
matrix.
The more pliable and distensible elastic
cartilage possesses, in addition to
collagen type II, an abundance of elastic
fibers within its matrix.
Elastic Cartilage, characterized by its
great pliability, contains significant
amounts of the protein elastin in the
matrix.
The more pliable and distensible elastic
cartilage possesses, in addition to
collagen type II, an abundance of elastic
fibers within its matrix.
3- Elastic cartilage, cont...3- Elastic cartilage, cont... Elastic Cartilage is found in:
- The auricle of the ear.
- The walls of the external auditory
canal.
- The auditory (Eustachian) tube.
- The epiglottis.
- The larynx.
Elastic Cartilage possesses a
perichondrium (like hyaline
cartilage) .
Elastic Cartilage is found in:
- The auricle of the ear.
- The walls of the external auditory
canal.
- The auditory (Eustachian) tube.
- The epiglottis.
- The larynx.
Elastic Cartilage possesses a
perichondrium (like hyaline
cartilage) .
Elastic cartilage
Articular cartilageArticular cartilage
Covers the surface of the bones of
movable joints.
Is devoid of perichondrium.
Is sustained by the diffusion of
oxygen and nutrients from the
synovial fluid.
Covers the surface of the bones of
movable joints.
Is devoid of perichondrium.
Is sustained by the diffusion of
oxygen and nutrients from the
synovial fluid.
PerichondriumPerichondrium
At the periphery of mature cartilage is
a zone of condensed supporting tissue
called perichondrium containing
chondroblasts with cartilage – forming
potential .
At the periphery of mature cartilage is
a zone of condensed supporting tissue
called perichondrium containing
chondroblasts with cartilage – forming
potential .
PerichondriumPerichondrium
• Is a sheath of dense connective tissue
that surrounds cartilage in most
places, forming an interface between
the cartilage and the tissue supported
by the cartilage.
Most cartilage is devoid of blood vessels
• Is a sheath of dense connective tissue
that surrounds cartilage in most
places, forming an interface between
the cartilage and the tissue supported
by the cartilage.
Most cartilage is devoid of blood vessels
PerichondriumPerichondrium
• All cartilage is covered by a layer of dense connective tissue (perichondrium)
(except in the articular cartilage of joints & fibro cartilage).
• It’s essential for the growth & maintenance of cartilage.
• It’s rich in collagen type I fibers & contains numerous fibroblasts.
• contains nerves lymphatic vessels.
• All cartilage is covered by a layer of dense connective tissue (perichondrium)
(except in the articular cartilage of joints & fibro cartilage).
• It’s essential for the growth & maintenance of cartilage.
• It’s rich in collagen type I fibers & contains numerous fibroblasts.
• contains nerves lymphatic vessels.
• Nutrition• Growing• Regenerating• Degenerative• Histogenesis
• Nutrition• Growing• Regenerating• Degenerative• Histogenesis
Cartilage Properties
Nutrition: is nourished by the diffusion of nutrients from capillaries in adjacent connective tissue (perichondrium) or by synovial fluid from joint cavities.
• Cartilage has no lymphatic vessels or nerves.
Nutrition: is nourished by the diffusion of nutrients from capillaries in adjacent connective tissue (perichondrium) or by synovial fluid from joint cavities.
• Cartilage has no lymphatic vessels or nerves.
Cartilage Properties
Growth : 1- Interstitial growth
2- Appositional growth Growth : 1- Interstitial growth
2- Appositional growth
• In all 3 forms, Cartilage is avascular (no vascular).
• In all 3 forms, Cartilage is avascular (no vascular).
1- Interstitial growth:
Resulting from the mitotic division of preexisting Chondrocytes.
Less important process.
important in increasing the length of long bones
occurs during the early phase of cartilage formation.
1- Interstitial growth:
Resulting from the mitotic division of preexisting Chondrocytes.
Less important process.
important in increasing the length of long bones
occurs during the early phase of cartilage formation.
The Growth of CartilageThe Growth of Cartilage
2- Appositional growth
Resulting from the differentiation of perichondrial cells.
Grows in girth only by opposition.
2- Appositional growth
Resulting from the differentiation of perichondrial cells.
Grows in girth only by opposition.
HistogenesisHistogenesis
A- mesenchyme.
B- Mitotic Proliferation of mesenchyme.
C- Chondroblasts. D- rise to isogenous
group.
A- mesenchyme.
B- Mitotic Proliferation of mesenchyme.
C- Chondroblasts. D- rise to isogenous
group.
Perichondrium & Hyaline cartilage
Degenerative changesDegenerative changes
• Hyaline cartilage is more susceptible to
degenerative aging processes ( in
contrast of other tissues).
• Calcification of the matrix, preceded by
an increase in the size & volume of the
chondrocytes and followed by their
death.
• Hyaline cartilage is more susceptible to
degenerative aging processes ( in
contrast of other tissues).
• Calcification of the matrix, preceded by
an increase in the size & volume of the
chondrocytes and followed by their
death.
Poor Regeneration of Cartilage TissuePoor Regeneration of Cartilage Tissue
• Except in young children, damage
cartilage regenerates with difficulty &
often incompletely by activity of the
perichondrium, which invades the
injured area and generates new
cartilage
• Except in young children, damage
cartilage regenerates with difficulty &
often incompletely by activity of the
perichondrium, which invades the
injured area and generates new
cartilage
Fibrocartilage, young animal
