Question

Atretic follicles occur in
A. Ovary
B. Thymus
C. Testis
D. Liver

Answer 1

Hint: Follicles degenerate until it reaches maturity. The atretic follicles appear before puberty. It is a periodic phenomenon in which immature ovarian follicles degenerate and are then reabsorbed.

Complete answer: An ovary is a follicle that degenerates until it reaches maturity. Atretic follicles appear in the ovary before puberty. The production of ovarian follicles atresia is a periodic phenomenon through which immature ovarian follicles degenerate and are then reabsorbed during the follicular phase of the menstrual cycle. The follicular atresia is a natural ovarian mechanism that regulates the number of follicles in the growing pool. Changes in the follicular atresia can be found secondary to xenobiotic administration. Since the growth of small preantral follicles is independent of gonadotropin, an improvement in atresia in these follicles is usually seen with direct-acting cytotoxic agents, heavy metals or radiations. When follicles evolve into the early antral phase and require development support for gonadotropin, there may be a rise in follicular atresia in the pool of follicles secondary to hormonal disruptions. Because the number of follicles in ovaries and the amount of apoptosis in the granulosa cells may differ greatly in control rats, a close comparison with controls is needed to identify a rise in the occurrence of follicular atresia. Through prolonged exposure, an increase in the number of follicular atresias leads to a decreased or absence of corpora lutea and eventually atrophy.
Hence, the correct answer is option A.

Note: The follicular atresia is a dynamic, hormonally mediated mechanism affecting all putative survival factors, e.g., insulin-like growth factor-1, epidermal growth factor, essential fibroblast growth factor, E2 and activin; and putative teratogenic factors, e.g., tumour necrosis factor-ш, GnRH, and androgens.