How are testosterone levels held in equilibrium?
FEMALE Human Reproduction
After puberty, the female reproductive (menstrual) cycle is
28 days
. It consists of:
1.
Ovarian cycle
- the maturation and release of eggs from the ovaries.
2.
Uterine Cycle
- the preparation of the uterus for the implantation of a fertilized egg
(zygote)
After Puberty, monthly hormonal cycles control the menstrual cycles
Hormones ensure that the timing of the uterine and ovarian cycles are in synch to give an
individual the best chance at successful pregnancy and reproduction.
Endometrium: lining of the uterus wall. It is vascularized and needed for a fertilized egg to
develop.
Female Sex Hormones
:
5.
Gonadotrophin-releasing hormone (GnRH):
released by the hypothalamus. stimulates
the anterior pituitary gland which triggers the release of FSH and LH
6.
Luteinizing hormone (LH):
Produced from anterior pituitary gland.
Causes ovulation to
occur. NO effect on the endometrium. --- High levels stimulate ovulation –STIMULATES
ESTROGEN PRODUCTION
7.
Follicle Stimulating Hormone (FSH):
stimulates the development of the follicle and
induces the production of estrogen. NO effect on the endometrium. ---Helps eggs
mature in follicles – AIDS IN FOLLICLE MATURATION
8.
Estrogen:
released from follicles in ovarian tissue. Repairs and thickens the
endometrium. Inhibits the hypothalamus and pituitary gland. (Less GnRH and therefore
LH FSH)
9.
Progesterone:
secreted from the Corps Luteum. Repairs and thickens (maintains) the
endometrium. MAINTAINS UTERINE LINING
Ovarian Cycle –
how eggs mature and are released from ovary
1.
Follicular Phase:
The development of the Graafian follicle (the egg). Menstruation
happens during the follicular phase.
2.
Ovulation:
The release of the egg from the ovary to the fallopian tube.
3.
Luteal Phase:
The formation and break down of the Corpus Luteum within the ovary. It
produces progesterone that interacts with uterus to maintain a thick endometrium.
Uterine Cycle –
how the uterus prepares for implantation of a fertilized egg
(zygote/embryo)
THREE stages of the uterine cycle (MPS)
1.
Menstrual Phase:
the breakdown and release of the endometrium by a period. Occurs
during the follicular phase of the ovarian cycle.
2.
Proliferative Phase:
The repair and build-up of the uterine lining. Occurs during the
follicular phase of the ovarian cycle. The walls are building up in preparation for the egg.
3.
Secretory Phase:
Maintaining the thickness of the uterine lining. (needed for the
implantation of the egg). Occurs during the Luteal phase of the ovarian cycle.
PLEASE look at the pictures Pucko put up on eLC “reproDiagrams” to understand below!!
Menstrual Phase (Days 1-5)
Day 1: GnRH releases and therefore FSH and LH is then released by the pituitary gland.
Day 2-5: This increase in FSH and LH stimulates follicle development.
Due to a reduction in estrogen and progesterone (from day 28) the lining breaks down and
deteriorates through the period.
