In addition, follicles that have formed an antrum are called antral follicles or Graafian follicles. Primordial follicles are activated to grow into antral follicles. Low intragastric pH stimulates antral D cells to release somatostatin. The follicles then transition to tertiary, or antral, follicles. An antral follicle is also called a "Graafian follicle". In the antral follicle, it may be regarded as an extension of the membrana granulosa. The selected follicles, called antral follicles, compete with each other for growth-inducing FSH. Maxillary antral washout involves puncturing the sinus and flushing with saline to clear the mucus. Women are about twice as often diagnosed with gastric antral vascular ectasia than men. Of these small antral follicles, 1 will become dominant and ovulate (in monoovulatory species). The maneuver is performed to determine if a perforation or antral communication exists. Fracture of maxilla&colon; Antral Lavage may result in escape of the fluid through fracture lines.