Dr. Archana RaniAssociate Professor

Department of AnatomyKGMU UP, Lucknow

2.12.2014

CARTILAGE

Modified connective tissueForms skeletal basis of some parts of bodyMatrix is firm giving it the characteristic

consistencyResists compressionAvascular (nutrients diffuse through matrix)Perichondrium is rich in blood vessels

PERICHONDRIUMDense irregularly

arranged fibrous tissue Ensheaths the cartilageComposed of cells &

matrixMatrix consists of fibres

& ground substanceHouses the blood vessels

that nourish chondrocytes

Present in most of the hyaline & elastic cartilage

Absent in fibrocartilage

Fibrous layer

Cellular layer

CHONDROBLASTMesenchymal

(embryologically)Progenitor of

chondrocytesLines border between

perichondrium and matrixProduce the intercellular

matrix and collagen fibresCells which become

imprisoned within this matrix become chondrocytes.

CHONDROCYTE

Mature cartilage cellReside in a space

called the lacunaIsogenous cell groupBasophilicClear areas = Golgi

and lipid droplets

CHONDROCYTE

Chondrocytes completely fill their lacunae

RER and euchromatic nuclei

Synthetically active, secrete matrix

Synthesize type II collagen, proteoglycans and chondronectin.

Cartilage matrix

RER

N

MATRIXProvides the rigidity,

elasticity, & resilienceFIBERS

Collagenous and elastic

GROUND SUBSTANCEGlycosaminoglycans

(chondroitin sulfates & keratan sulfate)

ProteoglycansWater

BasophilicTerritorial matrixInterterritorial matrix

CARTILAGE GROWTH

InterstitialNewly formed

cartilage grows by multiplication of cells throughout its substance.

AppositionalAddition of new

cartilage over the surface of existing cartilage.

TYPES OF CARTILAGE

HYALINE

ELASTIC

FIBROUS

CARTILAGE: LOCATIONS

HYALINE CARTILAGE Sites: Tracheal rings, nasal

septum, larynx, costal cartilage & articular surfaces of joints

Cartilage cells: Present singly or in groups of 2 or 4 cells inside lacunae

Cartilage Matrix: Collagen type II

Ground substance: Homogenous, clearly basophilic

Functions: supportive

ELASTIC CARTILAGE Sites: Auricle, ext.

auditory meatus, auditory tube, epiglottis, apices of arytenoid cartilage

Cartilage cells: larger, more numerous, packed more closely

Cartilage Matrix: elastic fibres, collagen type II

Ground substance: Rich in elastic fibres

Functions: supportive with resilience

Elastic fibers stain with orcein.

FIBROCARTILAGE Sites: intervertebral

discs, arytenoid cartilage (except apices), pubic symphysis, manubriosternal joint, articular disc of TM joint.

Cartilage cells: fewer, smaller, scattered singly or in rows

Cartilage Matrix: collagen type I & II

Ground substance: acidophilic

Functions: supportive with tensile strength

Intervertebral disc

Clinical application

Osteoarthritis

Pseudoachondroplasia

bonE

Modified connective tissueHighly vascular mineralized connective

tissue consisting of cells and dense intercellular organic matrix impregnated with inorganic salts.

Provide support & protection to the vital organs

Forms skeletal framework

Articular cartilage

Spongy bone

Marrow cavity

Compact bone (location of haversian systems)

Periosteum

Composition

Cells: a.Osteogenic cellsb.Osteoblastsc.Osteocytesd.Osteoclasts

• Fibers: collagen type I

• Ground Substance: Proteoglycans & glycoproteins

The matrix of bone is a mixture of organic (collagen) and inorganic (calcium phosphate)

90% of bone is matrix, with the remaining 10% made of osteocytes.

Microscopic Anatomy of BoneMicroscopic Anatomy of Bone

Figure 5.3

Lamellar arrangementLamellar arrangement

Slide 5.11a

Lamellae Rings around the

central canal

Sites of lacunae

Lacunae Cavities containing

bone cells (osteocytes)

Arranged in concentric rings

Figure 5.3

Slide 5.11b

Canaliculi

Tiny canals

Radiate from the central canal to lacunae

Form a transport system

Figure 5.3

Lamellar arrangementLamellar arrangement

compact bone

The morphofunctional unit of the bone is osteon, or Haversian system.

Lamellar pattern of compact bone:

i. Haversian system ii.Interstitial lamellaeiii.Circumferential

lamellae

T.S. through compact bone

‘Haversian Systems’

Dark spots are called ‘lacunae’ and would contain osteocytes in living bone

Central canal containing an artery, vein, lymph vessel and nerves

What happens when excessive bending force compresses the bone…!

compression

force

Clinical application

ScurvyRicketsOsteomalaciaOsteoporosisOsteogenesis imperfecta

Pseudoachondroplasia

Save your bones

Take home message

Aerobic exercisesLow impact, weight bearing

exercisesResistance exercises

References

1. diFiore’s Atlas of Histology with functional Correlations, 12th Edition.

2. Essentials of Anatomy for Dentistry Students,1st Edition.

3. Textbook of Histology, 3rd Edition.

MCQ

• Fibrous cartilage is present in:1.Auricle2.Nose3.Tracheal rings 4.Intervertebral discs

Label the following

A

BC

Don’t confuse this picture with the Liver Lobule!

MCQ• Elastic cartilage is present in:1.Apices of arytenoid cartilage2.Epiphysis3.Tracheal rings 4.Temporomandibular joints

MCQ• Hyaline cartilage is present in:1.Tracheal rings 2.External auditory meatus3.Semilunar cartilages of knee joint4.Intervertebral discs

MCQ

The blood vessels and nerves go inside the compact bone through:

1. Haversian canal2. Volkman’s canal3. Canaliculi4. Interstitial lamellae