Histology of Cartlage by Dr Roomi

8/2/2019 Histology of Cartlage by Dr Roomi

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HISTOLOGY OF

CARTILAGE

BY

DR. MUDASSAR ALI ROOMI (MBBS, M. Phil.)


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cartilage

One of the skeletal tissue, the other being thebone.

Rigid in nature like bone

Like all other C.T it has cells and intercellularmatrix.

Intercellular matrix= fibers +ground substance

incartilage, the ground substance has mainly

chondroitin SO4. In bonethe ground substance is mainly

impregnated with inorganic salts.


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Features ofthecartilage

Avascular

No lymphatics

No nerves


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Perichondrium

Found on peripheries of non-articular hyaline andelastic cartilage (MCS)

It has got two layers:

1. fibrouslayer:Peripheral layer is dense vascularconnective tissue with type I collagen

2. cellularlayer:Inner layer is chondrogenic andgives rise to chondroblasts that secrete cartilage

matrix Articular hyaline cartilage of bones and

fibrocartilage not lined by perichondrium (MCQ)


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Cartilage Matrix

Produced and maintained by chondrocytes andchondroblasts

Contains large GAGs, proteoglycan aggregates and

is highly hydrated

Allows diffusion and is semi rigid shock absorber

GAGs: chondroitin SO4, Keratan SO4 and

hyaluronic acid

Adhesive glycoprotein chondronectin binds cellsand fibrils to surrounding matrix


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Cartilage Cells

Primitive mesenchyme cells differentiate into

chondroblasts that synthesize the matrix

Mature cartilage cells, chondrocytes, becomeenclosed in lacunae

Inner layer of surrounding connective tissue

perichondrium is chondrogenic

Chondroblasts enlarge the cartilage


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Hyaline Cartilage

Mostcommoncartilage in the body

Hyaline= glass like

Covered by perichondrium

serves as a skeletal model for most bones (MCQ)

Replaced by bone during endochondral ossification

Contains type II collagen fibrils (MCQ)

Fibers are invisible Under light microscope because the

refractive index of type II collagen fibers and that ofground substance is the same (MCQ)


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Hyaline Cartilage


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Hyaline Cartilage


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Hyaline Cartilage


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Distribution ofhyalinecartilage

1. Articular cartilage (no perichondrium)

2. Costal cartilages

3. Nasal cartilages4. Cricoid, thyroid and arytenoid cartilages of

larynx

5. Cartilages of trachea and bronchi6. Epiphyseal cartilage of growing long bones.


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hyalinecartilage


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Elastic Cartilage

Contains branching elastic fibers in matrix and

is highly flexible

The fibers are visible but of elastic variety.

Occurs at places where support with flexibilty

is required.

Type II collagen fibers also present here (MCQ) This cartilage is covered by perichondium

(MCQ)


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Elastic Cartilage


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Distribution ofElastic cartilage

1. Auricle of the External ear

2. Cartilagenous part of the External auditary

meatus3. Epiglotis

4. Eustachian tube

5. Smal laryngeal cartilages (cuneiform andcorniculate)


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Fibrocartilage


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Histology of Fibrocartilage


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fibrocartilage


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Distribution of fibrocartilage

Intervertebral disc

Disc of the pubic symphysis

Intra-articular discs e.g. semilunar cartilages(menisci) of the knee joint

Glenoid labrum (of shoulder joint)

Acetabular labrum(of hip joint)


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Functions ofcartilage

1. Support soft tissues of the body

2. Provides smooth sliding surfaces in the joints

to facilitate the movements3. Cartilage is essential for the growth of long

bones before and after birth

Histology of Cartlage by Dr Roomi

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