Supporting c.t. 2009new

8/13/2019 Supporting c.t. 2009new

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SUPPORTING CONNECTIVE

TISSUE :

1. Cartilage

2. Bone


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General feature of cartilage :

Characteristic by firmness & resiliency. It form

fetal skeleton and persist where mechanical

properties are needed. Most fetal cartilage is

replace by bone.

Blood supply : most cartilage is enveloped by a

dense CT layer, the perichondrium, which

contains the vascular supply and fibroblast-like

stemcell from additional chondrocyte arise.


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Cartilage:

There are three 3 types cartilage:

1. Hyaline Cartilage

2. Elastic cartilage

3. Fibrous cartilage

They are differ in appearance andmechanical properties and in extracellular

matrix composition. No distinction is madeamong the cells in defferent cartilagetypes


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Component of cart. :

Cells

Extracellular substance :

Fibers : Hyaline cart.: type II collagen

Elastic cart. : Elastic & type II collagen

Fibrocart. : type I collagen ( coarse)Ground substance


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Cells :

Chondrocyte : in lacuna

Chondroblast: elliptic shape with the long

axis parallel to the surface.

Synthese collagen & matrix molecules

May appear in groups up to 8 cell called

isogenous (mitotic division of chondrocyte) In routine preparation retraction from

capsul, in living tissue fill the lacuna


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Matrix :

40 % consist of collagen type II

Ground substance : Proteoglycans : * chondroitin 4 sulfat

* Chodroitin 6 sulfat

* Keratan sulfat

* Hyaluronic acid

Glycoprotein, Glycoaminoglicans

Terrritorial matrix : Rich of glycoaminoglycans &

Poor in collagenGround substance composition control of nutrition

and oxygen to chondrocyte from perichondrium


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Perichondrium :

Outer layer(fibrous layer):

A layer dense CT. It is rich in collagen type I.It contains numerous fibroblast

Inner layer(chondrogenic layer) :Contains cells resemble fibroblasts, they arechondroblast. It harbors the vasc. supply.

All form of cartilage are avascular and nourished

by diffusion of nutrient from capillaries inperichondrium or by synovial fluid from jointcavities.


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Histogenesis :

All cartilage derived from embryonic

mesenchym

Cells at the first mesenchymal

condensation become a chondroblast and

secrete cartilage matrix.After it surroundedby cartilage matrix is termed chondrocyte.

Peripheral mesenchyme condenses

around the developing cartilage mass toform dense regular CT of the

perichondrium.


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Growth:

Cartilage grew in 2 processes; both involve mitosis

and deposition of additional matrix

Matrix synthesis is enchanced by growth hormon,

thyroxin and testosteron and inhibited by estradiol andexcess cortison

1. Interstitial growthinvolves the division of existingchondrocyte and gives rise to the isogenous group.

2. Appositional growthinvolves the differentiation intochondrocyte by chondroblast and stem cells on the

perichondriums inner surface


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Hyaline cartilage:

The chondrocyte are embedded in matrix

either singly or in isogenous groupsof 28 cells derived from one parent cell.

The space occupied by each chondrocyte

called alacuna, is visible only after cells

death or after shrinkage during tissue

processing.


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The matrix surrounding the chondrocytes

called the capsular (terr i to r ial matr ix), is

more basophilic and PAS (+) thanintercapsular (interterr i to r ial matr ix),

owing the higher sulfated GAG

consentration and lower collagen.

Hyaline cartilage is surrounded and

nourished by perichondrium except for

articular cartilage. Articular cartilage is

nourished by the synovial fluid in the jointcavity.


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The Location Of Hyaline Cart. :

Fetal skeletal tissue mainly made by hyaline

cart. As fetal cart. is replaced by bone,

hyaline cart. remains in the epiphyseal

plates at the ends of long bones.

Hyaline cart. is the most abundant and widelydistributed in the body. The tissue are found at.

The costal cart.

Most of the laryngeal cart.

The cart. ring of the trachea

The irregular cart. plates in the walls of the bronchi

Articular surface of the moveable joint.


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REGENERATION OF CARTILAGE

Injuries not repaired by the cartilage

Adult cells of cartilago likely do not divide

or have very limited ability.

Perichondrium proliferates to fill defect/gap

Fibroblasts transform into chondroblasts

Chondroblasts deposit new matrixFractures: may be united by permanent fibrous tissue

Fibrous tissue may be replaced by bone.


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Elastic cartilage :

Composition :

Elastic cart. contains dense network of branching elasticfiber and type II collagen, fibers. The colour is yellowishbecause the presence of elastin.

The perichondrium encloses elastic cartilage.

Elast ic cart i lage can be foun d at.

The external ear

The external auditory canals and auditory tubes The epiglottis

The corniculate & cuneiform of the larynx


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Fibrocartilage:

Intermediate between dense CT & hyalin Cart.

Border is not clear

Characterised by type I collagen

Chondrocyte (singly or isogenous) lies among

the densely packed type I collagen bundles

The capsular matrix contains type II collagen

No perichondrium..Fibrocartilage never occurs alone!

Merges with hyaline cartilage or surrounding

fibrous tissue


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Fibrocartilage

Occurrence:

Intervertebral disks

Pubic symphsis

Articular cartilagesand capsules

Lining tendon

grooves

Insertions of

tendons and

ligaments (some)

Intervertebral disc (Rat). C =

chondrocytes (H&E/Alcian Blue)


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BONE

dr. Arliek R.J. MS

Protection


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SupportProtection

Storage and productionLeverage


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Composition of Bone


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Function :

Supporting fragile structure

Protect vital organ,Harbors hematopoietic t

Reservoir calcium, phosphat

Composition :

*Cellular: osteocyte, osteoblast, osteoclast

*Intercellularbone matrix :

Fibers : collagen type I

Ground substance


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Type of bone tissue :

I. Architectur :* Spongy/ primary(woven)

*Compact/ secondary lamellar

II. Histogenesis :- Intramembranous

- Endochondral

III. Shape : long bone, flat bone


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Surface :

ExternalPeriosteum: double layered CT

* Outer : Fibrous layerdense CT

* Inner : Osteogenic layerloose CT

bone precursor

Sharpey fibers : periostal collagen fiberspenetrate

bone matrix to anchor periosteum to bone InternalEndosteum: thin, reticular CT- bone

& blood cell precursor, line marrow cavities


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Part of long bones :

Diaphysis : long bone shaft, walls of

compact bone & central marrow cavity line

with endosteum

Epiphysis : bulbous end, mostly spongy B.

Bones to form movable joint covered by

articular cartilage


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Bone tissue: obtaining thin sectionwith grinding bone slices until translucent &

demineralized in dilute acid or Ca chelating agentBone cel ls:a. Osteoprogenitor cell, stem cell found in :

Endosteum & Periosteum

2 types : 1. Form osteoblastfrom mesenchym

2. Form osteoclast-from monocyte

b. Osteoblast :*One cell thick sheet on surface-simple cuboid

*High alkaline phosphatase

*Secrete all organic the organic component*participate on bone mineralization


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C. Osteocyte :

* found in cavity in bone matrix -> called lacuna* Long, thin cytoplasm processes> filopodia

radiate from the cell body in canaliculi

* Osteocyte isolated from one another by

impermeable bone matrix and contact one

another at the tips of filopodiagap junction

nutrien & oxygen and dispose of waste.

* Incapable of mitosis

* Derived from osteoblast round lacunaflattened

lacuna


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d. Osteoclast

* bone resorbing cell

* Lying on bone surface in shallow depressionHowships lacuna.

* Large & multinucleated ( 250/ cell)

* acidophilic cytoplasmmany lysosome


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Primary bone :


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Primary bone :1. Intramembranous ossification/

Desmal - C.t membraneosteoblastosteoidmineralizedprimary oss. Center

trabeculaemembrane bone.

Ex. : - temporal bone

- parietal

- periostal bone collar in enchondral


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2. Endochondral ossification

Basic steps :

a.Cartilage modelreplacing with bone

b. Periostal bone collarintramembranoes

C. Zone : - Reserve- Proliferation

- Hypertrophy

- Calcificationatrophy- Ossification


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Supporting c.t. 2009new

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