Question

In hens egg, the flask shaped white yolk extending from the blastodisc to the centre of the yellow yolk is known as :

• A. Blastoderm
• B. Chalaza
• C. Latebra
• D. Nuclear of ponder

Hint:

The yolk of a hen's egg is deposited in alternating concentric layers of yellow yolk (deposited during the day when more fat is available) and white yolk (deposited at night), with the latebra at the center serving as the primary reservoir of white yolk.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
An avian egg contains several specialized structural components, including the shell, albumen, chalazae, and a centrally suspended yolk consisting of concentric layers of light and dark yolk.

Step 2: Detailed Explanation:
Let us analyze the terms provided in the options to identify the correct structure:
- Latebra:
The latebra is a flask-shaped or balloon-like central column of white yolk located in the center of the egg yolk.
It extends upward as a narrow neck towards the blastodisc (germinal disc) on the surface of the yolk.
The upper flared end of this neck is called the Nucleus of Pander (often misspelled as "nuclear of ponder").
- Blastoderm:
This is the early embryonic disc of cells formed by cleavage of the fertilized ovum, situated on the surface of the yolk.
- Chalaza:
The chalazae are two spiral, spring-like cords of dense albumen extending from the yolk membrane to the ends of the egg, which keep the yolk suspended in the center of the albumen.
- Nucleus of Pander (Nuclear of ponder):
This is the flattened, disc-shaped top of the latebra neck located immediately beneath the blastodisc.
Since the question asks for the entire flask-shaped white yolk structure extending from the blastodisc to the center, it refers to the Latebra.

Step 3: Final Answer:
This structure is known as the Latebra.