the concentrations of steroids in antral fluid , the number of granulosa cells , the status of the oocyte , and the diameter of each follicle were determined in human ovaries so that follicles at each stage of the menstrual cycle could be classified as large ( greater than or equal to 8 mm diameter ) or small ( less than 8 mm diameter ) and healthy or atretic .
C0029045
oocyte
C0018120
follicle