Graafian or Antral Follicles

Image from: Conti, M. and Chang, R. (2016). Folliculogenesis, Ovulation, and Luteogenesis.Endocrinology: Adult and Pediatric, [online] pp.2179-2191.e3. Available at: https://www.sciencedirect.com/science/article/pii/B9780323189071001256 [Accessed 7 Mar. 2020].

These follicles tend to be rather big and belong to a heterogenous family as they have liquor folliculi inside an antrum (Conti and Chang, 2016). There are two specific groups of graafian follicles: healthy and atretic (Conti and Chang, 2016). As shown in the diagram on the left, both of these cells follow the same growth cycle to the preovulatory step (Conti and Chang, 2016). The predominant difference between both these types of graafian follicles is whether or not apoptosis occurs in the granulosa cells (Conti and Chang, 2016). In the non-dominant type, apoptosis is activated and in the dominant type it is not, and the cells go on to differentiate and grow (Conti and Chang, 2016).

References: CONTI, M.&CHANG, R.J., 2016. Folliculogenesis, Ovulation, and Luteogenesis. In: Endocrinology: Adult and PediatricSeventh Edition ed., pp. 2179-2191.e3.