Menarche, Puberty and menstrual disorders Flashcards
what is the hypothalamic, pituitary, and ovarian axis?
Gonadotropin releasing hormone (GnRH) from the hypothalamus stimulates the follicle stimulating hormone (FSH) and the lutenizing hormone (LH) from the anterior pituitary that stimulate estrogen and progesterone from the ovarian follicle
how can the normal ovulatory cycle be divided into?
Follicular phase
-begins with the onset of menstruation and culminates in the preovulatory surge of LH
Luteal phase
-begins with the onset of the preovulatory LH surge and ends with the first day of menses
what does the regressing corpus luteum mean for the ovulatory cycle?
Decreasing levels of estradiol and progesterone from regressing corpus luteum of the preceding cycle will initiate an increase in FSH by a negative feed back mechanism which stimulates follicular growth and estradiol secretion
what does LH and FSH stimulate in the ovarian follicle?
LH stimulates:
-the theca cells to produce androgens (androstenedione and testosterone)
FSH stimulates:
-the granulosa cells to convert the androgens made by the theca cells to estrogens (E1 estrone and E2 estradiol)
what occurs in the luteal phase?
Both the LH and FSH are significantly suppressed through the negative feedback effect of the elevated circulating estradiol and progesterone
If conception does not occur progesterone and estradiol levels decline near the end of the luteal phase as a result of corpus luteal regression
FSH will then rise which initiates new follicular growth for the next cycle
this always occurs 14 days after ovulation
characteristics of Gonadotropin releasing hormone?
Decapeptide synthesized in the arcuate nucleus
Responsible for the synthesis and release of LH and FSH
-both LH and FSH are present in 2 different forms (releasable and storage) within the pituitary gonadotrophs
GnRH reaches the anterior pituitary and stimulates the synthesis and release of FSH and LH into the curculation
Estradiol appears to enhance the hypothalamic release of GnRH and induce the midcycle LH surge
Gonadotropins have an inhibitory effect on GnRH release
how does estrogen levels behave in the ovarian cycle?
during the the follicular development estradiol levels are low
one week prior to ovulation estradiol (E2) levels begin to increase and will reach a maximium 1 day prior to the midcycle LH surge
after the peak and before ovulation there is a marked and precipitous fall
During the luteal phase, estradiol rises to a maximum 5 to 7 days after ovulation and returns back to baseline when the corpus luteum regresses
how does progestins levels behave in the ovarian cycle
During the follicular development the ovary secretes only very small amounts of progesterone
-the bulk of the progesterone comes from the peripheral conversion of the adrenal pregnenolone and pregnenolone sulfate
Prior to ovulation the unruptured luteinizing graafian (mature) follicle begins to produce increasing amounts of progesterone
secretion of progesterone by the corpus luteum reaches a maximum 5-7 days after ovulation and returns to baseline before menstruation
what is a graafian follicle?
it is a mature follicle in an adult ovary that is the dominant follicle
the innermost 3-4 layers of multiplying granulosa cells become cuboidal and adherent to the ovum this is known as the cumulus oophorus
A fluid filled antrum forms along the granulosa cells
- will enlarge and the centrally located primary oocyte migrates to the wall of the follicle
- innermost layer of the granulosa cells of the cumulus become elongated and form the corona rdiata
- the corona radiata is released with the oocyte at ovulation
what does the preovulatory LH surge initiate?
sequence of biochemical and structural changes that result in ovulation
cells on the follicular wall surface degenerate and a stigma forms, the follicular basement membrane bulges through the stigma
when this ruptures the oocyte is expelled into the peritoneal cavity and ovulation has occured
Function of the corpus luteum?
After ovulation the granulosa cells of the ruptured follicle undergo luteinization
The luteinized granulosa cells, theca cells, capillaries and connective tissue form the corpus luteum
Corpus luteum produces copious amounts of progesterone and some estradiol that functions for 9-10 days
if pregnancy does not occur, menses ensues and the corpus luteum is gradually replaced by an avascular scar called the corpus albicans
what are the two zones of the endometrium?
Endometrium is responsive to circulating progestins, androgens, and estrogens
Outer portion or Functionalis:
- this layer undergoes cyclic changes in morphology during the menstrual cycle and is sloughed off at menstruation
- contains spiral arteries
Inner portion of basalis
- this layer remains relatively unchanged during each cycle and after menstruation provides stem cells for the renewal of the functionalis layer
- contains basal arteries
endometrial changes in the menstrual cycle?
only portion of the cycle that is visualized externally
the first day of menstruation is known as cycle day 1
- Disruption and disintegration of the endometrial glands and stroma, leukocyte infiltration and red blood cell extravasion
- sloughing of the functionalis layer and compression of the basalis layer
Endometrial changes in the proliferative phase
Characterized by endometrial growth/proliferation secondary to estrogenic stimulation
increase in the length of the spiral arteries and numerous mitoses can be seen in these tissues
endometrial changes in the secretory phase
Following ovulation, progesterone secretion by the corpus luteum stimulates the glandular cells to secrete mucus, glycogen and other substances
glands become tortuous and lumen are dilated and filled with these substances
stroma becomes edematous
mitosis is rare
Spiral arteries continue to extend into superficial layer of the endometrium and become convoluted
endometrial lining reaches its maximal thickness
if conception does not occur by day 23 the corpus luteum begins to regress, secretion of progesterone and estradiol declines, and the endometrium undergoes involution
what medications can affect the coagulation pathway that would affect menstruation?
Warfarin, Aspirin, Clopidogrel can impair coagulation system and be associated with heavy bleeding
What occurs in an initial reproductive health visit?
occurs between the ages of 13-15 years
- important for building trust between physician and patient
- provide preventative health care services
- informational and guidance rather than problem focused
age appropriate discussion of:
- pubertal development
- normal menses
- timing of visits
- STIs
- Pregnancy prevention
- sexual orientation and gender identitiy
- rape prevention
a general exam, visual exam, and external pelvic exam may be indicated
when is the first pap test recommended?
recommended by ACOG at the age of 21 years
what is an importan vaccine that women and men should get to prevent cervical cancer?
at the ages of 9-26 they should look into the human papillomavirus vaccine
offers protection against cervical cancer, cervical dysplasia, vulvar or vaginal dysplasia, and genital warts associated with:
- Gardasil HPV genotypes 6,11,16, and 18
- Gardasil 9 genotypes 6, 11, 16, 18, 31, 33, 45, 52, and 58
when does menarche begin?
Median age of menarche is 12.43 years
- 10% at 11.11
- 90% at 13.75
occurs within 2-3 years after thelarche (breast budding) at tanner stage IV and is rare before tanner stage III