Menstrual cycle - look at MIND MAP Flashcards
What are the two major circulating oestrogens? Where are these produced?
Oestrones and Oestradiol. Primarily produced in ovaries directly, or can be converteed by aromatase into Androstenedione.
Two peaks one estrogen come in the menstural cycle, when are they?
- Just before ovulation
- one mid luteal phase
The primary location of androgen production is by the theca cells in the ovary. What other androgens are produced by the ovaries, and where else can they be produced?
- Androstenediol
- Dehydropiandrosterone (DHEA)
- Small amounts of testerone
Adrenal cortex also produces around half of androstenedione and DHEA, and essentially all of the sulfated form of DHEA.
Summarise roles of oestrogen
- facilitate growth of ovarian follicles
- regulate uterine blood flow
- Impotnat in development of secondary sex characteritics during puberty
What molecule is required for the production of progesterone?
Where is progestrone produced?
What are it’s roles?
Cholesterol
Corpus lutem, adrenal glands and placena
Endometrial matienance and smooth muscle control. Maintenance of pregnancy. Mammary gland development (during pregnancy)
What is congenital adrenal hyperplasia caused by? What is the presentation?
21-hydroxylase deficiency or, by one step ower down in the pathway, 11Beta-hydroxylase deficiency.
Ambigious genitalia at birth, early puberty (precocious puberty), anovulation, hirsutism (excess hair).
you can have disroders where you have aromatase deficiency, or aromatase excess. What would each of these result in, and what would the presentation be?
- Either prevention of oestrogen synthesis
- Or excessive conversion of andrgens to oestrogens
For the former - you would expect ambigious genitalia
For the latter, you would expect femeninisation of the male genitalia.
Regulation of female reproduction is gverned by the Hypothalamic-pituitary-ovaruan axis, as well as the uterus.
The hypothalamus is responsible for releasing the master regulator, ??????. It’s main job is to stimulate the release of the gonadtrophins from the ?????, which are ???? and ????.
As a result, the gonadotrophins allow the ovary (and the placenta) are thus able to respond to the gonadtrophins and secrete ??????.
Gonadotrophin releasing hormone (GnRH)
Anterior Pituitary
Follice-stimulating-hormone (FSH)
Lutenising hormone (LH
Steroid sex hormones (oestrogen and progesterones)
Neurosecretory cells in the hypothalamus produce GnRH. It is a ?? amino acid peptide with ??? half-life. It is secreted into the portal vessels of the anterior pituitary, and is secreted in a ??? manner. GnRH activates ??? receptor, which stimulates the release of gonadorophins.
10
short
pulsatile
GnRH-receptor in anterior pituitary
State the subtances produced from the anterior and posterior pituitary
The 3rd level of hormonal control is the ovaries (2nd being anterior pituitary and 1st being hypothalamus). Levels of FSH and LH will have triggered follice maturation and also regulate the production of hormones by the ovary. This includes estrogen, progesterone and testosterone. These travel via the blood and can have various affects on the Uterus, vagina and cervix.
What is the role of follice stimulating follice?
What is the role of Lutenizing hormone?
initiates recruitment and supports growth of follicles in the ovaries - by acting on FSH-R on granulosa cells.
It is going to act on the OTHER cells of the follicle, the THECA cells, supporting their development. . The recetors for LH are only abundant at the primary follice stage. It’s main role is to trigger ovulation.
When thinking about the menstrual cycle - it’s good to firstly split it up into what happens before ovulation and what happens after ovulation.
The mesntrual cycle can actually be split into two cycles - the Ovarian cycle and the Uterine cycle - since this is where the major changes/effects are occuring.
When thinking about the ovarian cycle, what are the two phases?
When thinking about the uterine cycle, what are the three phases?
Follicular phase - preovulation.
Luteal phase -post ovulation
Menses(menstuation) and proliferative - preovulaion
Secretory phase - post ovulation
let’s look at the follicular phase. At this point, a woman will have a bunch of primary oocytes which are currently inside primordial follices.
Describe the changes the primordial follices will go through in the follicular phase.
- The primordial follice starts with a single layer of follicular cells
- This first change is to a primary follice - this basically a slightly bigger follice - although the ovum size is basically the same
- A secondary follicle is formed - with the formation of antrum
- Next is Tertiary/graffian follicle (will be secondary oocyte at this stage) - the dominant follcle that will go onto be ovulated is usually dertmined at this stage - whilst unsuccessful follicles will undergo atresia.
Turner syndrome - female missing X chromsome - often accompanied with poor oestrogen levels. Cannot ovulate properly.
Kallman’s syndrome - GnRH deficiency
