Menstruation Flashcards
What is the average length of a menstrual cycle?
28 days
What is the average length of a menstrual flow?
4-6 days
What is the other term for the first menstruation?
Menarche
What are the four body structures involved in menstruation?
- hypothalamus
- anterior pituitary
- ovaries
- uterus
What initiates the menstrual cycle?
Release of GnRH from the hypothalamus
How does GnRH affect the pituitary gland?
Sigals the pituitary gland to release gonadotropic hormones to let the ovaries produce estrogen
What is the relationship between GnRH and estrogen?
If estrogen levels are high enough, GnRH is inhibited
What is another term for the anterior pituitary gland?
Adenohypophysis
What stimulates the growth of the uterine lining during the second half of the menstrual cycle?
LH
What hormone becomes the most active at the midpoint of the cycle and is responsible for ovulation?
LH
What hormone is responsible for the maturation of the ovum?
FSH
At what point of the cycle does the ovum divide by mitotic and meiotic division?
Midpoint
How does FSH affect the ovaries?
Causes the oocyte to grow and mature
What does the oocyte produce as it grows?
Follicular fluid that contains a high degree of estrogen and some progesterone
What is the graafian folicle?
the small ovum accompanied by the follicular membrane and fluid
What causes the graafian follicle to rupture leading to ovulation?
prostaglandins
What causes the release of prostaglandins?
LH
When does ovulation begin?
14 days before the end of the cycle
What happens to the ovarian follicles after ovulation?
produces lutein and is renamed to the corpus luteum
What causes the follicles to produce lutein?
LH
How many weeks does the corpus luteum remain if the ovum is fertilized?
16-20 weeks
How many days does it take for the ovum to atrophy if unfertilized?
4-5
How many days does the corpus luteum remain for if the ovum is unfertilized?
8-10 days
Uterine changes that occur monthly as a result of stimulation from ___________ and _____________ produced by the ovaries
estrogen and progesterone
What is the first phase of the menstrual cycle?
Proliferative (or estrogenic, follicular, postmenstrual)
When does the proliferative phase occur?
After menstrual flow (around 5-14 days)
What causes the endometrium to proliferate (grow) during this phase?
estrogen
What occurs in the proliferstive phase?
ovaries produce estrogen as instructed by the FSH
What is the second phase of the menstrual cycle?
Secretory (or luteal, progestational, premenstrual)
What hormone is formed in the secretory phase?
Progesterone
What secretes progesterone in the secretory phase?
Corpus luteum
(Secretory phase) The glands of the uterine endometrium become ____________ or ___________ in appearance
corkscrew or twisted
(Secretory phase) The uterine endometrium is dilated with quantities of _________ and ________
glycogen and mucin
What is the third phase of the menstrual cycle?
Ischemic
(Ischemic phase) If ___________ does not occur, the corpus luteum begins to regress after __ to __ days
fertilization; 8-10
What decreases in the ischemic phase?
Production of progesterone
(Ischemic phase) What happens when the progesterone levels drop?
Endometrium begins to degenarate, the capillaries rupture and the endometrium sloughs off
What is the fourth phase of the menstrual cycle?
Menses (or menstrual flow)
What composes the menstrual flow?
- mixture of blood from ruptured capillaries
- mucin
- fragments of endometrial tissue
- ovu
The first day of menstrual flow is used to mark the ____________ _______ of a new menstrual cycle
beginning day
