Histology of Cartilage

Questions and Answers

What is the primary function of chondronectin in cartilage matrix?

To synthesize proteoglycan molecules

To mediate the adherence of chondrocytes to the ECM (correct)

To provide firm consistency to cartilage

To produce type II collagen fibers

What type of collagen fibers are present in fibrocartilage and perichondrium?

Type I collagen (correct)

Type III collagen

Type II collagen

Elastic fibers

What is the typical arrangement of chondrocytes in hyaline cartilage?

In large groups throughout the cartilage

In a linear fashion

In small isogenous groups or isolated (correct)

In a lattice-like pattern

What is the primary component of the outer region of the perichondrium?

Fibroblasts and collagen type I fibers Signup and view all the answers

What is the function of the perichondrium in cartilage growth and maintenance?

To provide a source for new chondroblasts Signup and view all the answers

What is the characteristic of the extracellular matrix in hyaline cartilage?

Homogeneous with type II collagen and aggrecan Signup and view all the answers

What is the reason for the formation of groups of chondrocytes in hyaline cartilage?

Due to the division of a single parent cell Signup and view all the answers

What is the characteristic of hyaline cartilage in the fresh state?

Homogeneous and semitransparent Signup and view all the answers

What is the characteristic of cartilage that allows it to provide firm structural support for soft tissues?

High tensile strength Signup and view all the answers

What is the function of chondroblasts in cartilage development?

To differentiate into chondrocytes Signup and view all the answers

What is the main component of the ground substance in cartilage?

Proteoglycans Signup and view all the answers

What is the typical diameter of mature chondrocytes?

40 μm or more Signup and view all the answers

What is the primary source of nutrition for cartilage?

Diffusion through the extracellular matrix Signup and view all the answers

Which type of cartilage is characterized by the presence of elastic fibers?

Elastic cartilage Signup and view all the answers

What is the function of the Golgi complex in chondrocytes?

Secretion of ECM components Signup and view all the answers

What is the primary component of the proteoglycan molecule in cartilage?

Aggrecan Signup and view all the answers

What is the primary location of cartilage differentiation during embryonic development?

From the center towards the periphery Signup and view all the answers

What is the term for the cartilage cells during the period of rapid proliferation?

Chondroblasts Signup and view all the answers

What is the function of the perichondrium in cartilage growth?

Is the source of progenitor cells for appositional growth Signup and view all the answers

What is the characteristic of the cytoplasm of chondroblasts and chondrocytes?

Basophilic and rich in RER Signup and view all the answers

What is the significance of interstitial growth in cartilaginous regions within long bones?

Increases the length of the bone Signup and view all the answers

What is the purpose of the ECM in cartilage formation?

Encloses the cells in their lacunae and separates them Signup and view all the answers

During which stage of cartilage growth is matrix synthesis more important?

Interstitial growth Signup and view all the answers

What is true about the arrangement of chondrocytes in the intervertebral disc?

They are arranged in axially arranged aggregates Signup and view all the answers

What is the main difference between elastic cartilage and hyaline cartilage?

The presence of elastic fibers Signup and view all the answers

What is the primary function of elastic cartilage in the auditory tubes?

To allow for flexibility and recovery after deformation Signup and view all the answers

What type of collagen fibers are present in fibrocartilage?

Both type I and type II collagen Signup and view all the answers

Where is fibrocartilage typically found?

In intervertebral discs and attachments of certain ligaments Signup and view all the answers

What is the characteristic of the matrix in fibrocartilage?

It is sparse and contains few proteoglycans Signup and view all the answers

What is the primary difference between fibrocartilage and hyaline cartilage?

The presence of dense connective tissue Signup and view all the answers

What is the function of fibrocartilage in intervertebral discs?

To serve as a shock absorber and cushioning support tissue Signup and view all the answers

What is unique about the arrangement of chondrocytes in fibrocartilage?

They are arranged in aligned isogenous aggregates Signup and view all the answers

What is the term used to describe groups of cartilage cells?

Cell-nests Signup and view all the answers

Where are the cells found to be small and elongated in a direction parallel to the surface?

Towards the periphery of the cartilage Signup and view all the answers

What is the term used to describe the deep staining matrix found around lacunae and cell nests?

Territorial matrix Signup and view all the answers

In adults, where is hyaline cartilage typically located?

In the ventral ends of ribs, where they articulate with the sternum Signup and view all the answers

What is the function of the epiphyseal plate in growing children?

To facilitate bone growth Signup and view all the answers

What happens to hyaline cartilage in old people?

It undergoes calcification Signup and view all the answers

What type of cartilage does not undergo calcification or ossification?

Articular cartilage Signup and view all the answers

What is the function of hyaline cartilage in joints?

To provide smooth, low-friction surfaces in joints Signup and view all the answers

Study Notes

Characteristics of Cartilage

Cartilage is a special form of connective tissue that develops from the mesenchyme.
It consists of cells (chondrocytes and chondroblasts) and extracellular matrix.
Cartilage is nonvascular (avascular) and receives its nutrition via diffusion through the extracellular matrix.
It exhibits tensile strength, provides firm structural support for soft tissues, allows flexibility without distortion, and is resilient to compression.

Types of Cartilage

There are three main types of cartilage in the body:
- Hyaline cartilage
- Elastic cartilage
- Fibrocartilage

Cells of Cartilage

Chondroblasts are embryonic cartilage-producing cells.
Chondrocytes are mature cells that synthesize and maintain all ECM components.
Chondrocytes lie in spaces (or lacunae) present in the matrix.
Chondrocytes synthesize and maintain all ECM components.
The cytoplasm of chondrocytes may also contain glycogen and lipids.

Ground Substance

The ground substance of cartilage is made up of complex molecules containing proteins and carbohydrates (proteoglycans).
The carbohydrates are chemically glycosaminoglycans (GAG) which include:
- Chondroitin sulphate
- Keratin sulphate
- Hyaluronic acid
The core protein is aggrecan.
Proteoglycan molecules are tightly bound, along with the water content, these molecules form a firm gel that gives cartilage its firm consistency.

Fibers of Cartilage

Fibers of cartilage are collagen and elastic fibers according to the type of cartilage.
The collagen fibers present in cartilage are described as type II collagen.

Perichondrium

Except in the articular cartilage of joints, all hyaline cartilage is covered by a layer of dense connective tissue, the perichondrium.
The perichondrium is essential for the growth and maintenance of cartilage.

Hyaline Cartilage

Hyaline cartilage is the most common of the three types.
It is homogeneous and semitransparent in the fresh state, and covered by perichondrium except at epiphyses and articular cartilage.
The extracellular matrix is homogeneous, with type II collagen and aggrecan.
Major cells are chondrocytes and chondroblasts.

Elastic Cartilage

Elastic cartilage is essentially similar to hyaline cartilage except that it contains an abundant network of elastic fibers.
It is more flexible than hyaline cartilage, and readily recovers its shape after being deformed.
Elastic cartilage is found in the auricle of the ear, the walls of the external auditory canals, the auditory (Eustachian) tubes, and the epiglottis, and the upper respiratory tract.

Fibrocartilage

Fibrocartilage is essentially a mingling of hyaline cartilage and dense connective tissue.
It is found in intervertebral discs, in attachments of certain ligaments, and in the pubic symphysis, and serves as very tough, yet cushioning support tissue for bone.

Cartilage Formation, Growth, and Repair

All cartilage forms from embryonic mesenchyme in the process of chondrogenesis.
During embryonic development, cartilage differentiation takes place primarily from the center outward.
Once formed, the cartilage tissue enlarges both by interstitial growth, involving mitotic division of preexisting chondrocytes, and by appositional growth, which involves chondroblast differentiation from progenitor cells in the perichondrium.

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Description

This quiz covers the characteristics, features, and types of cartilage, a type of connective tissue. It also explores growth and regeneration of cartilage.