Cartilage (Part 2 of 2)

Question 1

Name the primary germ layer that cartilage is derived from?

Answer 1

Cartilage = connective tissue = mesoderm

Question 2

Describe the functions of cartilage?

Answer 2

Support:
Found in locations such as the trachea and external ear, where it provides structural support.

Providing smooth joint surfaces:
Provides a smooth surface to reduce friction between the bones forming the joint.

Providing a model for bone formation:
Most bones in the body are formed by endochondral ossification, where a hyaline cartilage model is slowly replaced by bone.

Question 3

Describe the basic components and cell types in cartilage?

Condroblast
Condrocyte

Answer 3

Chondroblast:
- Immature cartilage cells.
- Derived from stem cells at the surface of the cartilage.
- Once they become entrapped in the cartilage matrix they produce, they become chondrocytes.

Chondrocyte:
- Mature cartilage cells.
- Derived from chondroblast.
- Occupy small spaces within the cartilage matrix called lacunae.
- Responsible for maintaining the cartilage matrix.

Question 4

Describe the structure, function and location of the three types of cartilage - hyaline cartilage?

Answer 4

Structure:
1. The chondrocytes within their lacunae are scattered throughout the cartilage matrix and the collagen fibres are not readily visible on histological slides.

Function:
1. Support other structures.
2. Provide a model for bone formation, as it forms the cartilage precursor in endochondral ossification.

Location:
1. Found in parts of the resp tract (larynx and trachea).
2. Costal cartilages attached to the ribs.

Question 5

Describe the structure, function and location of the three types of cartilage - fibrocartilage?

Answer 5

Structure:
1. Contains many interwoven collagen fibres, which are visible on histological slides.
2. Chondrocytes within their lacunae are often arranged in parallel rows between the collagen fibres.
3. Little ground substance.

Function:
1. Provide strength and act as a shock absorber.

Location:
1. Intervertebral discs.
2. In the pubic symphysis.
3. In the wedge-shaped pads of cartilage in the knee joint called menisci.

Question 6

Describe the structure, function and location of the three types of cartilage - elastic cartilage?

Answer 6

Structure:
1. Contains many interwoven elastic fibres.
2. Chondrocytes within their lacunae are often closely packed and are surrounded by a visible meshwork of elastic fibres.

Function:
1. Support other structures while allowing for flexibility.

Location:
1. In the external ear and nose.
2. In the epiglottis of the larynx, which prevents from from entering the airways.

Question 7

Describe the structure, function and location of the perichondrium?

Answer 7

Structure:
1. Outer fibrous layer made of dense irregular CT.
2. Inner cellular layer containing cartilage stem cells and chondroblasts.

Function:
1. Protect the cartilage.
2. Anchor the cartilage to other structures.
3. Provide cells for cartilage growth and repair.

Location:
1. The tough sheet covering the external surface of cartilage.

Question 8

What is interesting about cartilage?

Answer 8

Cartilage is avascular, meaning that it lacks blood vessels.

∴ Cartilage receives its blood supply via diffusion from the blood vessels outside the perichondrium.

Question 9

Name the types of cartilage covered by perichondrium?

Answer 9

Hyaline cartilage:
Covered by perichondrium.

***Articular cartilage = lacks perichondrium.
–> A type of hyaline cartilage covering the articular surfaces of bones.

Fibrocartilage:
Lacks perichondrium.

Elastic cartilage:
Covered by perichondrium.