Unit 2 - Gamete production & fertilisation Hormonal control of reproduction Key Area 1 & 2 Flashcards
What does the testes produce?
Testes produce sperm in the seminiferous tubules and testosterone in the interstitial cells
What does the prostate gland and seminal vesicles do?
The prostate gland and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm.
What do ovaries contain and what is a follicle?
The ovaries contain immature ova in various stages of development. Each ovum is surrounded by a follicle that protects the developing ovum and secretes hormones.
Describe fertilisation
Mature ova are released into the oviduct where they may be fertilised by sperm to form a zygote. (The nucleus of the sperm and egg fuses together to form a zygote.)
a) What does the pituitary gland do ?
b) What causes it to act that way?
c) Whats the consequence of that act?
The pituitary gland is stimulated to release follicle stimulating hormone (FSH), luteinising hormone (LH) or interstitial cell stimulating hormone (ICSH) by a releaser hormone produced in the hypothalamus. This triggers the onset of puberty.
What does FSH stand for?
Follicle stimulating hormone
What does LH stand for?
Luteinising hormone
What does ICSH stand for
Interstitial cell stimulating hormone
What is the function of Follicle stimulating hormone (FSH)?
FSH promotes sperm production
What does Interstitial cell stimulating hormone (ICSH) stimulate?
ICSH stimulates the production of the hormone testosterone.
What does testosterone stimulate?
Testosterone also stimulates sperm
production and activates the prostate gland
and seminal vesicles
What do FSH and ICSH control?
Negative feedback control of testosterone by FSH and ICSH
Describe the menstrual cycle?
The menstrual cycle takes approximately 28
days with the first day of menstruation
regarded as day one of the cycle.
What does Oestrogen stimulate?
Oestrogen stimulates proliferation of the endometrium preparing it for implantation, and affects the consistency of cervical mucus making it more easily penetrated by sperm.
What do peak levels of oestrogen stimulate?
Peak levels of oestrogen stimulate a surge in the secretion of LH. This surge in LH triggers ovulation.
What is ovulation?
Ovulation is the release of an egg (ovum) from a follicle in the ovary. It usually occurs around the mid-point of the menstrual cycle.
What happens in the luteal phase of ovulation?
In the luteal phase the follicle develops into a corpus luteum which secretes progesterone.
What does Prgesterone promote in the luteal stage of ovulation?
Progesterone promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs.
What does the negative feedback of ovarian hormones do?
The negative feedback effect of the ovarian hormones on the pituitary gland and the secretion of FSH and LH prevent further follicles from developing.
What does the negative feedback of ovarian hormones do?
The negative feedback effect of the ovarian
hormones on the pituitary gland and the
secretion of FSH and LH prevent further
follicles from developing.
What does a lack of LH lead to?
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 corpus luteum if fertilisation does occur?
If fertilisation does occur the corpus luteum
does not degenerate and progesterone levels
remain high.
