Question

Which of the following layers in the antral follicle is acellular?
A)Granulosa
B)Theca interna
C)Stroma
D)Zona pellucida

Answer 1

A layer is called acellular when it is either not made up of cells or is not divided into cells.

Complete answer:
Graffian follicles are also antral follicles are the follicles which forms an antrum during the menstruation. Antral follicles are present in a small fluid filled sac containing immature eggs. It is a resting follicle and can be measured on the second, third and fifth day of the cycle.

Option a: Granulosa cells are somatic cells which are closely related to the development of the female gamete in the ovary. These cells are not acellular. Therefore, this is the incorrect option.
Option b: Theca interna are a type of theca cells which are involved in estrogen synthesis. It is responsible for producing androgens. But this layer is not acellular, therefore this is the incorrect option.
Option c: Stroma is basically a connective tissue present in the ovary which has an abundant supply of blood vessels. As it is a tissue, it definitely contains cells, therefore, this is the incorrect option.
Option d: Zona pellucida is formed during the development of the follicle. It is a glycoprotein polymer capsule which is acellular and forms around the oocyte. It separates the oocyte from the nearby granulosa cells. After ovulation, the layer remains with the oocyte and helps in penetrating of sperm as it contains enzymes which help in the process of penetration. Therefore, this is the correct option.

Thus, the correct option is (d) Zona pellucida.

Note: The function of zona pellucida is as follows,

1. It helps in communication between the oocytes and follicle cells
2. It protects the eggs, embryos and oocytes during development