Histology of Cartilage

Questions and Answers

What is the consistency of cartilage?

Firm

What are the three types of cartilage?

Hyaline cartilage, Yellow elastic fibrocartilage, White fibrocartilage

What is the function of the perichondrium?

Acts as a mechanical support to the cartilage

Acts as a barrier to the cartilage

Acts as a waste removal system for the cartilage

Acts as a source of O2 and nutrients to the cartilage cells (correct)

What is the difference between young and mature chondrocytes?

Young chondrocytes are flat cells with open-face nuclei and pale basophilic cytoplasm, while mature chondrocytes are oval or rounded and have rounded and open-face nuclei. Signup and view all the answers

What are chondrocytes also known as?

Chondrocytes cells Signup and view all the answers

What is the function of chondrocytes?

They synthesize and secrete the components of the cartilage matrix and are responsible for the growth of the cartilage. Signup and view all the answers

Where is hyaline cartilage present?

Tracheal ring, Intervertebral disc, Symphysis pubis, Ear pinna Signup and view all the answers

What is the composition of the cartilage matrix?

Collagen fibers, proteoglycans, glycoproteins, and proteins Signup and view all the answers

What is the difference between yellow elastic fibrocartilage and hyaline cartilage?

Yellow elastic fibrocartilage contains an abundant network of elastic fibers, whereas hyaline cartilage does not. Signup and view all the answers

Where is yellow elastic fibrocartilage present?

Auricle of the ear, External auditory meatus, Eustachian tube, Epiglottis Signup and view all the answers

What is the difference between white fibrocartilage and hyaline cartilage?

White fibrocartilage is not covered by perichondrium, and its matrix contains bundles of coarse type I collagen fibers. Signup and view all the answers

Where is white fibrocartilage present?

Intervertebral discs, Semilunar cartilage of knee joints, Symphysis pubis, Lips of glenoid cavity, Terminal parts of tendons Signup and view all the answers

Perichondrium is not present in which type of cartilage?

White fibrocartilage Signup and view all the answers

Study Notes

Cartilage

Cartilage is a type of connective tissue with a firm consistency of the extracellular matrix.
There are three types of cartilage: hyaline cartilage, yellow elastic fibrocartilage, and white fibrocartilage.

Hyaline Cartilage

Appearance: translucent pale blue in fresh state
Consistency: firm or rigid with some degree of flexibility
Structure:
- Formed of perichondrium, cartilage cells (chondrocytes), and cartilage matrix
Sites:
- Constitutes the majority of the foetal skeleton
- Articular surface of bones
- Costal cartilage in the thoracic cage
- Nose, trachea, and bronchi

Perichondrium

A vascular connective tissue membrane that surrounds the cartilage except at the articular surfaces of the joints
Formed of two layers: outer fibrous layer and inner chondrogenic layer
Function:
- Acts as a source of O2 and nutrients to the cartilage cells
- The inner chondrogenic layer is responsible for new cartilage formation

Cartilage Cells (Chondrocytes)

There are two types of chondrocytes: young chondrocytes and mature "old" chondrocytes
Young chondrocytes:
- Arise from the inner chondrogenic layer
- Flat cells with open-face nuclei and pale basophilic cytoplasm
- Present singly in their lacunae at the periphery of the cartilage and parallel to the perichondrium
Mature "old" chondrocytes:
- Site: deep in the cartilage in the form of rows perpendicular to the perichondrium
- Shape: oval or rounded when single, and triangular or semicircular when in groups
- Have rounded and open-face nuclei and granular, basophilic cytoplasm rich in glycogen, fat, and phosphatase enzyme
Function:
- Synthesize and secrete the components of the cartilage matrix
- Can divide, responsible for the growth of the cartilage

Cartilage Matrix

General characters:
- Rubbery in consistency
- Non-vascular
Staining reaction:
- Appears homogenous basophilic by Hx and E due to the presence of sulphated glycosaminoglycans
- Shows strong PAS positivity
Components:
- Collagen fibers (Type II)
- Proteoglycans (chondritin 4 sulphate and 6 sulphate)
- Glycoprotein (chondronectin)
- Protein (chondrocalcin)

Yellow Elastic Fibrocartilage

Appearance: yellow in color due to the presence of elastic fibers
Consistency: elastic and flexible due to the presence of elastic fibers
Structure:
- The matrix contains an abundant network of elastic fibers
- Can be stained by standard elastic stains (e.g. Verhoeff's stains)
Sites:
- Auricle of the ear
- External auditory meatus
- Eustachian tube
- Epiglottis

White Fibrocartilage

Appearance: white in fresh state
Consistency: tense and resists stretch due to the presence of collagen fibers
Structure:
- Differs from hyaline cartilage in:
  - Not covered by perichondrium but surrounded by dense C.T. rich in blood vessels
  - Chondrocytes are arranged in rows or columns
  - Matrix contains bundles of coarse type I collagen fibers in between rows of chondrocytes
Sites:
- Intervertebral discs
- Semilunar cartilage of knee joints
- Symphysis pubis
- Lips of glenoid cavity
- Terminal parts of tendons

Description

This quiz covers the histological structure and differentiation of various types of cartilage, including hyaline, yellow elastic fibrocartilage, and white fibrocartilage. Learn about the characteristics of each type and their differences.