Lecture 3: Preparation for pregnancy and ovulation Flashcards
Define myometrium
Thickest layer of smooth muscle tissue
What is the structure and layers of the endometrium
-columnar surface epithelium with uterine glands, connective tissue base, and spiral arterioles
The layers of the endothelium are the functional and the basal layers
Describe the cervix
mucosal surface is characterized by crypts
epithelium produces a glycoprotein rich cervical mucous (thinnest in ovulation)
Describe the vaginal
nonkeratinized squamous epithelium that secretes glycogen throughout the menstrual cycle
Why is the pH of the vagina low?
because the glycogen breakdown causes acidic components to be present
What are the two sub cycles of the menstrual cycle?
- ovarian cycle
2. endometrial cycle
What are the ovarian cycle substages?
- follicular phase
- ovulation
- luteal phase
What are the substages of the endometrial cycle?
- menstrual phase
- Proliferation phase
- secretory phase
Describe the follicular phase of the ovarian cycle
days 1-14 of the menstrual cycle
-FSH helps the development and maturation of the Graafuan follicle
Describe ovulation
occurs on day 14
caused by a rise in FSH And a sharp rise in LH; egg is released from the follicle. The graafian follicle continues to secrete progesterone
Describe the egg as it is released from the Graafian follicle during ovulation
- surrounded by follicle cells (corona radiata)
- egg is arrested in second half of meiosis (metaphase 2)
- egg will not complete meiosis unless fertilized
- has a little buddy with it called the polar body
Describe the luteal phase of the ovarian cycle
The remaining portion of the follicle secrete estrogen and progesterone
breakdown of the membrane granulaosa allows the growth of blood vessels into the cavity of the ruptured follicle
luteinization of granulose cells
corpus luteum is formed from residual theca and granulose cells
What happens in the luteal phase if fertilization does not occur?
- corpus luteum regresses and the levels of progesterone and estradiol decreases, beginning the next menstraul cycle
- inhibin inhibits FSHwhich causes the corpus luteum to regress
- formation of the corpus albicans
How is the corpus luteum broken down?
apoptosis and uterine luteolytic factors
What happens if fertilization does occur in the luteal phase of the ovarian cycle?
chorioic gonadotropin from the future placental tissues maintain the function of the corpus luteum
granulosa lutein cells are replaced by theca lutein cells
corpus luteum is function for several months into pregnancy
Describe the menstraul phase of the endometrial cycle
endometrium sloughs off
menstruation begins with the vasoconstriction (mediated by prostaglandins) of the spiral arteries)
inflammatory cells come in and break down the endometrium
clotting process is inactivated and the women can menstruate
Describe the proliferation phase of the endometrial cycle
Due to an increase in the levels of estradiol secreted by the granulose cells of the ovarian follicle
endometrial thickness goes from 1-2mm to 8-10 mm by day 14
blood vessels grow via the old cells from the previous endometrium that were deep enough to survive the period
Near the end: sharp rise in estradiol levels
Describe the secretory phase of the endometrial cycle
levels of estrogen decrease and the endometrial growth stops
mucous glands go nuts
spiral arteriole expand and highly vascularize
controlled by rising levels of progesterone that is secreted by the granulose and the theca cells of the follicle
What happens in the endometrial cycle if the egg is fertilized
It is implanted about 7 days after ovulation
What happens in the endometrial cycle if the egg is not fertilized?
estradiol and progesterone levels decrease and cause vasoconstriction of the spiral arterioles which allows for the sloughing off
Describe what is happening on day 14 prior to ovulation
There is a mature graafian follicle. The oocyte is arrested in diplotene of prophase 1
follicle expands with FSH and LH
meiosis 1 is completed but arrested at metaphase of meiosis 2
formation of stigma (follicle weak spot)
Describe what happens on day 14 during ovulation
LH surge
increased blood flow tot the follicle wall that thickens the outer layers
release of fluid from the blood vessels
local production of matrix metalloproteinases
secretion of hyaluronic acid
inflammatory action resulting in the rupture of the follicle wall
What is ovulated?
ovum at metaphase 2 first polar body zona pellucida corona radiata expanded cumulus oophorus
