Question

In which of the following, elastic cartilage is present?
(a) Pinna
(b) Eustachian tube
(c) Epiglottis
(d) All of the above

Answer 1

Hint: Elastic cartilage is also known as yellow cartilage. It contains elastic fiber networks and collagen type II fibers. The principal protein is elastin. Elastic cartilage provides strength, and elasticity, and maintains the shape of certain structures. They are known to have certain functions in the ear and part of the larynx.

Complete answer:
Elastic cartilage is the type of cartilage present in the outer ear or pinna, Eustachian tube, and epiglottis. It provides strength and maintains the shape. Elastic cartilage is histologically similar to hyaline cartilage but contains many yellow elastic fibers lying in a solid matrix. These fibers form bundles that appear dark under a microscope. These fibers give elastic cartilage great flexibility so that it is able to withstand repeated bending. The chondrocytes lie between the fibers. Elastin fibers stain dark purple/black with Verhoeff’s stain present in the outer ear, Eustachian tube, and epiglottis.

Additional Information:
- Cartilage is a smooth elastic tissue, rubber-like padding that covers and protects the ends of long bones at the joints and nerves. It is a structural component of the rib cage, the ear, the nose, the bronchial tubes, the intervertebral discs, etc.
- It is not as hard and rigid as bone, but it is much stiffer and much less flexible than muscle. Cartilage does not contain blood vessels or nerves.
 - Nutrition is supplied to the chondrocytes by diffusion. Cartilage is classified into three types, elastic cartilage, hyaline cartilage, and fibrocartilage.
So, the correct answer is '(d) All of the above'.

Note:
- In elastic cartilage, the cells are closer together creating less intercellular space. Elastic cartilage is found in the external ear flaps and in parts of the larynx etc.
- Hyaline cartilage has fewer cells than elastic cartilage. There is more intercellular space. Hyaline cartilage is found in the nose, ears, trachea, parts of the larynx, and smaller respiratory tubes.
- Fibrous cartilage has the fewest cells so it has the most intercellular space. Fibrous cartilage is found in the spine and the menisci.