exam 1 - menstruation Flashcards
useful facts
-normal length of the menstrual cycle is 21-35 days
-normal menstrual period lasts from hours to 7 days
-average amount of blood loss -> 30 cc
-range of normal blood loss -> minimal amount to 80 cc
-ovaries contain about 6 mil oocytes at 20 wks gestational age
-by menarche 300,000 are left due to atresia
-normally, a pt will ovulate up to 500x over reproductive life span -> 500 periods
commonly used terms
-first menses- menarche
-infrequent menses- oligomenorrhea
-absent menses (at least 6 months)- amenorrhea
-frequent menses- polymenorrhea
-heavy menses- menorrhagia
-bleeding between menses- metrorrhagia
-post coital bleeding- infection?
-excessive and prolonged bleeding at irregular and/or frequent intervals- menometrorrhagia
structures, hormones and target organs of the menstrual cycle
-estradiol turns off FSH not LH
-after the oocyte leaves the follicle -> now called corpus luteum -> makes progesterone
-progesterone necessary for every part of pregnancy
events in the menstrual cycle
ovarian events:
- follicular phase: 7-21 days
- ovulation
- luteal phase: almost always 14 days
endometrial events:
-menstruation
-production of proliferative endometrium (due to effect of estradiol)- rebuilding
-production of secretory endometrium (due to effect of progesterone)- prepares for possibility of pregnancy
US c-sections
35% are c-sections in the US
menstrual cycle graphic
days 1-6 (as example): menstruation and early follicular phase
-Day 1: menstruation begins
-The functional/basil layer of the endometrium has become necrotic and is shed
-Within one or more days -> hypothalamus secretes GnRH
-Secreted in a pulsatile fashion
-1 pulse every 70-90’
-GnRH stimulates secretion of FSH from anterior pituitary ->FSH downregulates GnRH
-FSH stimulates development of several follicles of the ovary
-Follicles contain several types of cells
-Granulosa cells produce estrogen (E), primarily estradiol
-Theca cells produce androgens
-> Only one double bond separates androgens from estrogens
-Easily aromatized to E
-E downregulates FSH
-E upregulates LH and LH receptor growth in ovary
theca and granulosa cells of ovarian follicle
days 6-12: late follicular phase: the ovarian epithelium
-surge of LH 26hrs before ovulation
- Estrogen levels increase
- increased E upregulates LH
- LH receptors increse
day 12-13: pre-ovulation; day 14: ovulation
-LH surge: sudden increase in LH occurs 36hrs prior to ovulation
prostaglandins are secreted just prior to ovulation:
-Cause disruption of follicular epithelium
-Ovulation occurs
-A small amount of blood may be seen at site of follicular rupture -> Hemoperitoneum may cause mild pain lasting <24 hrs known as mittelschmerz
-Blood degrades into its constituents
-Lipids turn the follicle yellow
-After ovulation, the follicle becomes known as the corpus luteum (Latin, “yellow body”)
retrieval of occytes at ovulation (for oocyte donation or in vitro fetilization)
days 15-28: luteal phase
The corpus luteum now produces progesterone (P) for remainder of luteal phase
-pic- corpus luteum cyst
-ultrasonic image of corpus luteum cyst
endometrial events
menstruation- days 1-6 (for example) - functional layer of endometrium (EM) is sloughed off down to basalis of EM
proliferative phase: days 7-14- E stimulates thickening of EM- reparative process stops bleeding
secretory phase: days 15-28- P stimulates EM to become edematous and vascular
Endometrial stripe in late luteal phase, right before menses vs
- 4x thicker = normal
There’s an oocyte on the loose, sperm running amok, and a lush, vascular endometrium…now what?
5% chance of pregnancy after intercourse
