This document summarizes the hormonal control of gametogenesis in males and females. It explains that the hypothalamus and pituitary gland control the process by secreting gonadotrophic hormones like follicle stimulating hormone (FSH) and luteinizing hormone (LH) in response to gonadotropin-releasing hormone (GnRH). In females, it describes the menstrual cycle process where FSH and LH stimulate egg production and uterine thickening in response to estrogen and progesterone levels throughout the cycle.

1. Hormonal control of gametogenesis
• Control centre – hypothalamus and
pituitary gland (act as controlling link
between the nervous system and the
endocrine system)
• Pituitary gland:
– 2 gonadotrophic hormones
• stimulate gonads
• secreted in response to gonadotrophin
releasing hormone (GnRH)
– follicle stimulating hormone (FSH)
– luteinising hormone (LH)
ALBIO9700/2006JK

2. ALBIO9700/2006JK

3. Menstrual cycle and hormonal
control of oogenesis
• In the female, gametes and sex hormones
production is cyclic (menstrual cycle)
• The first day of the cycle is counted from
the start of menstruation (shedding of
the bloody lining of the uterus
(endometrium) through the vagina)
• 2 halves:
– Egg is produced
– Uterus is prepared for implantation in case the
egg is fertilised
ALBIO9700/2006JK

4. ALBIO9700/2006JK

5. • Anterior lobe (pituitary gland) – FSH in blood – ovary – stimulates
development of a primary follicle
• Maturing follicle – oestrogen in blood – uterus and anterior lobe
(pituitary gland) – stimulates repair and thickening of
endometrium (uterus)/inhibits secretion of FSH and LH (anterior
lobe) except when increased greatly
• LH – ovary – causes ovulation; stimulates the remains of Graafian
follicle to develop into the corpus luteum; stimulates secretion of
progesterone; reduces oestrogen production, which in turn reduces
FSH and LH
• Corpus luteum – progesterone and oestrogen – uterus and
anterior lobe (pituitary gland) – stimulates glandular activity in
endometrium; helps oestrogen in maintaining thickness of
uterus/enhance the negative feedback effects of oestrogen and
inhibit FSH and LH secretion (anterior lobe)
– Absence of FSH – no second egg
– Progesterone – temperature rise in female body
• If pregnant, corpus luteum receives hormone stimulus from
implanted embryo (if not it degenerates)
– As it degenerates, supply of oestrogen and and progesterone is cut off
– FSH no longer inhibited and switched on (completing cycle)
– Lining of uterus breaks down (menstruation)
ALBIO9700/2006JK