Oogenesis

what is oogenesis

production of female gametes

where do oocytes develop

within follicles (fluid filled spaces providing protection and nutrition for developing oocyte

what are primary follicles

formed before birth

only mature when level of Follicle stimulating hormone (FSH) increases

primary follicle contains primary oocyte

what is a secondary follicle

develop from primary follicles and contain secondary oocytes

as it matures it becomes fluid filled and secondary oocyte becomes surrounded by small follicular cells known as corona radiata

what is a Graafian follicle

a fully. mature follicle

formed when secondary oocyte is ready to be released at ovulation

What stages of oogenesis occur before birth

1. germinal epithelium cells (2n) undergo mitosis to produce two Oogonia (2n)

2. One oogonia used to regenerate a germinal epithelium cell, the other undergoes growth, interphase, and then pauses at prophase 1

3. A primary oocyte is formed

what stages of oogenesis happen between puberty and menopause

1. primary oocyte undergoes rest of meiosis 1 and the cytoplasm divides unevenly

   •a secondary oocyte and a 1st polar body are formed

2. Secondary oocyte and 1st polar body undergo meiosis 2 but stop at metaphase 2

3. Secondary oocyte and 1st polar body released from ovary in ovulation

What happens if fertilisation occurs

• meiosis 2 completes

• forms a fertilised ovum with a 1st and 2nd polar body

what happens if fertilisation doesn’t occur

• secondary oocyte and 1st polar body released in menstrual blood