Hormonal control of Reproduction Flashcards
State the site of gamete production in males
Sperm are produced by seminiferous tubules in the testes.
How can seminiferous tubules produce sperm?
The tubules are lined with specialised germline cells which can carry out meiosis - a special type of cell division that produces gametes only.
State the site of testosterone production
Testosterone (the male sex hormone) is produced by interstitial cells, in the testes. Interstitial cells are found in-between the seminiferous tubules.
What is fertilisation
Fertilisation is the fusion of two haploid gamete nuclei to form a diploid zygote - this depends on the mobility of the sperm (their ability to swim and having fluid to swim in)
What is the function of the seminal vesicles and the prostate gland?
The fluid secreted by both the seminal vesicle and prostate gland maintains the mobility and viability of sperm.
These fluid, along with the sperm, make up the liquid called semen.
What is the term for cells which divide to form gametes?
Germline cells
What are the stages of the hormonal control of reproduction in males?
1) The hypothalamus produces a releaser hormone which triggers the onset of puberty.
2) The pituitary gland produces FSH and ICSH.
3) FSH and ICSH travels through the bloodstream to locate their target tissues at the testes.
4) FSH promotes sperm production in the seminiferous tubules. ICSH promotes testosterone production in the interstitial cells.
What are the roles of testosterone?
As the male sex hormone, testosterone has two roles to play.
1) Stimulates sperm production same as (FSH).
2) Activates the prostate gland and seminal vesicles to produce secretions that maintain the mobility and viability of sperm.
How is hormone production in males regulated?
Testosterone production is regulated by negative feedback control.
How does negative feedback control regulate testosterone levels?
1) High levels of testosterone inhibits FSH and ICSH production at the pituitary gland, leading to a decrease in testosterone production.
2) Low levels of testosterone stimulates FSH and ICSH at the pituitary gland, leading to an increase in the production of testosterone.
What are the phases of the menstrual cycle?
These are a series of events lasting approximately 28 days - day 1 of the cycle if the first day of menstruation.
Phase 1) The follicular phase (days 1-14 approx)
Phase 2) The Luteal Phase (days 14-28 approx)
What are the stages of the hormonal control of puberty and the menstrual cycle?
1) The hypothalamus produces a releaser hormone which triggers the onset of puberty.
2) The pituitary gland produces FSH and LH.
The Follicular Phase
3) FSH travels through the bloodstream to locate its target tissue at the ovary.
4) FSH stimulates the development of a follicle (becomes a mature follicle) inside the ovary, oestrogen is produced from the follicle.
The luteal phase
5) LH travels through the bloodstream to locate its target tissues at the ovaries.
6) LH stimulates ovulation (around day 14 of the cycle) and the development of the empty mature follicle into a corpus luteum which secretes progesterone until menstruation (the ovum will be shed along with the endometrium.), if fertilisation does not take place.
What allows the luteul phase phase of the menstrual cycle to begin ?
Peak levels of oestrogen stimulates a surge in the production of LH in the pituitary gland, this surge in LH triggers ovulation, allowing the luteal phase of the menstrual cycle to begin.
What is the role of oestrogen?
As the primary female sex hormone, oestrogen has two roles to play:
1) Stimulates the proliferation of the endometrium, preparing it for implantation.
2) Thins the cervical mucus, making it more easily penetrated by sperm.
What is the role of progesterone ?
As the secondary female sex hormone, progesterone has one role to play:
1) Promotes further proliferation and vascularisation of the endometrium, preparing it for implantation.
