Flashcards in Key Area 2.2 - Hormonal Control of Reproduction Deck (20):
What are hormones?
Chemical messengers produced the endocrine glands.
Where are hormones released?
Directly into the bloodstream and travel to their target tissue or organ where they have their effect.
What do hormones control?
The onset of puberty, sperm production and the menstrual cycle.
What does the hypothalamus secret at puberty?
A released hormone that targets the pituitary gland.
What hormones are released when the pituitary gland is stimulated?
Follicle stimulating hormone (FSH), luteinising hormone (LH) in women and interstitial cell stimulating hormone (ICSH) in men.
What does FSH promote?
Sperm production in the seminiferous tubules of the testes.
What does ICHS stimulate?
The interstitial cells in the testes to produce the male sex hormone called testosterone.
What does testosterone stimulate?
Sperm production in the seminiferous tubules and also activates the prostate gland and the seminal vesicles to produce their fluid secretions.
What is overproduction of testosterone prevented by?
Explain negative feedback.
High testosterone levels inhibit the secretion of FSH and ICSH from the pituitary gland, resulting in a decrease in the production of the testosterone by the interstitial cells.
What hormones are associated with the menstrual cycle?
Describe what happens in the follicular phase of the menstrual cycle.
FSH stimulates the development and maturation of follicle surrounding the ovum and the production of the sex hormone oestrogen by the follicle.
What does oestrogen stimulate?
The repair and vascularisation of the endometrium, thickening it and preparing it for implantation.
Describe what happens in the literal phase.
A surge of LH triggers ovulation and then stimulates the development of the corpus luteum from the follicle.
What does LH stimulate?
The corpus luteum to secrete the sex hormone progesterone.
What does progesterone promote?
The dither development and vascularisation of the endometrium preparing it for implantation of a blastocyst, if fertilisation occurs.
What does high levels of oestrogen and progesterone inhibit?
The secretion of FSH and LH by the pituitary gland, this prevents further follicles from developing.
Describe negative feedback in females.
The inhibition of FSH and LH by high levels of oestrogen and progesterone.
What happens if fertilisation doesn’t occur?
There is a drop in LH levels which causes the corpus luteum to break down, in turn causing a decrease in progesterone and oestrogen levels.