Cartilage is a type of specialized connective tissue. Like the fibroblast and the adipocyte, the chondroblast derives from a mesenchymal stem cell.
Similar to typical connective tissue, the cartilage consists of cells embedded in Extracellular matrix. The perichondrium is formed by a layer of undifferentiated cells that can differentiate into chondroblasts which during their secretory process, become entrapped within the matrix they secreted and become known as chondrocytes, occupying small cavities called lacunae.
The space between the chondrocyte and the wall of the lacuna seen in histologic preparations is an artifact of fixation.
Because cartilage does not possess a vascular supply, nourishment must reach these cells by diffusion through the matrix from the vascular supply located in the connective tissue, perichondrium, surrounding the cartilage.
 Perichondrium is absent in Fibrocartilage.
 Articular cartilage (Type of Hyaline Cartilage) lacks a perichondrium.
There are three major types of cartilage
1. Hyaline cartilage.
2. Elastic cartilage.
The cartilage contains
The three different types of cartilage differs in combination of these in which they are present.
CELLS = Chondrocytes, usually arranged in groups.
FIBRES = Fibres are type II collagen and are sparsely located.
ECM = Matrix is abundant and so basophilic in appearance. ( See image below ) www.pgmeeuploads.com
CELLS = Chondrocytes arranged in parallel rows between bundles of collagen fibers.
FIBRES = Fibres are type I collagen and are abundant
ECM = Matrix is sparse and predominant component is collagen Type I so eosinophilic in apperance. (see image below)www.pgmeeuploads.com
CELLS = Chondrocytes are more numerous and larger than the chondrocytes of its hyaline counterpart.
FIBRES = Coarse elastic fibers in its matrix that impart an opaque yellowish tinge (Gross appearance) to it and a greater degree of flexibility. Note that it also contains type II collagen
ECM = Matrix of elastic cartilage is less abundant than the matrix of hyaline cartilage. (See image below)www.pgmeeuploads.com
Q1. Gene responsible for differentiation of Mesenchymal cells into Chondroblasts/Carilage formation :- www.pgmeeuploads.com
Ans =  Mesenchymal cells located in the vicinity where cartilage is to form assemble into chondrification centers, express the gene Sox9,and differentiate into chondroblasts. Sox9-null chondrogenic cells remain in the perichondrium and do not differentiate into chondrocytes. www.pgmeeuploads.com
Also remember : Sox9 participates in male sex determination.
Mutations of the Sox9 gene cause skeletal defects (campomelic dysplasia), and sex reversal (XY females).
Q2. Which of the following is elastic cartilage :-www.pgmeeuploads.com
 Articular ends of long bones
 Auditory tube
 Intervertebral disks
 Pubic symphysis
Ans =  &  www.pgmeeuploads.com
 Epiglottis = Elastic cartilage
 Articular ends of long bones = Hyaline
 Auditory tube = Elastic cartilage
 Intervertebral disks = Fibrocartilage
 Pubic symphysis = Fibrocartilage
Hyaline cartilage = It occurs in the temporary skeleton of the embryo, articular cartilage, Epiphysis and the cartilage of the respiratory tract (nose, larynx*, trachea and bronchi) and costal cartilages.
Larynx = All except Epiglottis & cuneiform cartilage of larynx. These two are elastic. www.pgmeeuploads.com
Elastic cartilage = Pinna of ear, walls of auditory canal, auditory tube, epiglottis, cuneiform cartilage of larynx.
Fibrocartilage = Intervertebral disks, articular disks of the knee, sternoclavicular joints, and pubic symphysis and sites of insertion of tendon and ligament into bone.
High Yield Point : Appositional growth is the major method of growth of cartilage except in locations where a perichondrium is absent (e.g. at articular joints and epiphyseal plates of long bones).
High yield Point : Aggrecan is a large proteoglycan "characteristic" of cartilage. It provides a hydrated gel-like structure that facilitates the load bearing properties of cartilage.
High Yield Point : The adhesive glycoprotein which facilitates
the adhesion among the various cellular and extracellular elements of hyaline cartilage = Chondronectin
High Yield Point www.pgmeeuploads.com
Q. Most abundant collagen in Cartilage :- Type II
Q. Most abunt collagen in Fibrocartilage :- Type I