Cartilage

Question 1

Where is cartilage found in the embryo?

Answer 1

Cartilage is more prevalent in the embryo than in adult. The skeleton is initially mostly cartilage. Bone replaces cartilage during foetal development and childhood.

Question 2

Where is cartilage found in the adult?

Answer 2

Skeleton (costal cartilage) ribs
Nose
External ear
Trachea and larynx

Question 3

Describe, in general terms, the function of cartilage.

Answer 3

Cartilage is a semi-rigid, flexible connective tissue. It gives support in tissues and organs and acts as a scaffold for bone development.
It is avascular and aneural, and obtains nutrition by long range diffusion from blood vessels on its periphery.
Cartilage has high mechanical strength.

Question 4

Describe the composition of cartilage.

Answer 4

Cells; chondroblasts; chondrocytes.
Extracellular matrix; around 75% water, a mixture of molecules and fibres.

Question 5

Name the 3 kinds of cartilage.

Answer 5

Hyaline
Elastic
Fibrocartilage

Question 6

Describe hyaline cartilage.

Answer 6

Found in articular, costal and nasal. The chemical composition of the matrices of each of these is different. They have a glassy appearance and are the weakest type of cartilage.

Question 7

Describe elastic cartilage.

Answer 7

Found in external ear, larynx and epiglottis, where it maintains their shapes.
Elastic cartilage is flexible and resilient, containing elastic and collagen fibres.
The chondrocytes are found among a threadlike network of collagen fibres within the matrix.

Question 8

Describe fibrocartilage.

Answer 8

Found in joint capsules, ligament and tendon insertions and intervertebral discs. Contains dense bundles of collagen fibres. Along with alternating layers of hyaline cartilage matrix. Fibrocartilage is the strongest type of cartilage.

Question 9

Describe nutrition of cartilage.

Answer 9

Cartilage is avascular and so is nourished by cartilage channels = pores from blood vessels into cartilage matrix. Most cells are distant from vascular supply, so use diffusion from surface (perichondral) vessels.
Articular cartilage obtains nutrients via synovial fluid.
This means cartilage can never be very thick.

Question 10

What happens to cartilage as we age?

Answer 10

Water content of cartilage decreases and this causes;
Reduced shock absorption
Less protection of articular surfaces and increased risk of damage.