Hormonal control of fertility Flashcards
What hormones are released by the picture gland
Hormones released by the pituitary gland at puberty are:
• Follicle stimulating hormones (FSH)
Luteinising hormone (LH)
• Interstitial cell stimulating (ICSH)
What triggers puberty
A releaser hormone produced in the hypothalamus stimulates the release of hormones by the pituitary gland to trigger the onset of puberty.
describe the hormonal control of sperm production
FSH promotes sperm production and ICSH stimulates the production of testosterone. Testosterone promotes sperm production and activates the prostate gland and seminal vesicles
Describe the negative feedback of testosterone
Pituitary gland releases FSH and ICSH
Stimulates production of testosterone in the testes
Testosterone concentration increases in the blood inhibiting the production of FSH ICSH.
Decrease in FSH and ICSH stops the production of testosterone
Testosterone concentration drops
Describe the menstrual cycle
The menstrual cycle takes approximately twenty-eight days and the first day of menstruation is regarded as day one.
The menstrual cycle is split into three distinctive phases:
• The follicular phase
• The luteal phase
• The menstrual phase.
describe the role of FSH
Follicle stimulating hormones (FSH) stimulates the development of the follicle and production of oestrogen by the follicle in the follicular phase.
describe the effects of oestrogen
Oestrogen stimulates the proliferation of the endometrium (lining of the uterus) preparing it for implantation and affects the consistency of cervical mucus. The mucus becomes thinner and waterier in consistency making it more easily penetrated by sperm.
Describe the release of LH
Peak levels of oestrogen stimulate the surge in the secretion of LH. The surge in LH triggers ovulation.
Describe ovulation
Ovulation is the release of (ovum) from a follicle in the ovary. It usually occurs around the mid-point of the menstrual cycle.
Describe the luteal phase
The follicle develops into a corpus luteum which secretes progesterone.
What is the role of progesterone
Progesterone promotes further development and vascularisation (development of capillaries) of the endometrium (lining of the uterus) preparing it for implantation if fertilisation occurs.
Progesterone and oestrogen inhibit further secretion of FSH and LH to prevent further follicles from developing. The lack of LH leads to degeneration of the corpus luteum with a subsequent drop in progesterone levels leading to menstruation.
What happens to the progesterone if fertilisation occurs
Progesterone levels remain high and the corpus luteum does not regenerate if fertilisation occurs.
