The physiology of the menstrual cycle Flashcards
What is the the duration of a normal menstrual cycle?
what is the average
21- 35 days
28days
What is menstruation?
Menstruation is the periodic discharge of blood, mucus and uterine cellular debris at cyclic intervals from menarche to menopause.
At what age do we expect menarche?
10 to 16
Average 13
how much blood loss is expected during the mensturating period?
less than 80mls
What does blood from one’s menses not coagulate?
due to the secretion of fibrinolysin enzyme (plasmin) secreted by the endometrium
Define the following ;
Dysmenorrhea
Molimina
Mittleschmerz
Dysmenorrhea-it is the lower abdominal pain shortly before or during menstruation in heh absence of pathologic findings that account for those symptoms
Molimina-mild symptoms that occur before menstruation occurs(headache, acne, bloating, negative moods, cramps, fatigue and tenderness of breast)
Mittelschmerz-physiological preovulatory pain in female individuals of reproductive age
What is the effect of estrogen on the endometrium?
-stimulates the repair of the endometrium.
What is the effect of progesterone on the endometrium?
Stimulates thickening of and maintains endometrium
What releases hCG? And what is the role of it?
-Embryo(if pregnant)
-Stimulates the production of progesterone.
What are the phases of the Ovarian Cycle?
1.Follicular
2.Ovulatory phase
3.Luteal phase
Describe what occurs during the follicular phase of the ovarian cycle?
Which hormone causes the ovulatory phase?
Lutenizing hormone
Describe the vents that occur during the luteal phase?
What is the function of inhibin?
It inhibits the release of FSH
What are the phases of the uterine cycle?
1.Menstrual and Proliferative phase
2.The secretory phase
Which layer of the endometrium is sloughed off during menstruation?
Stratum functionale
What causes shedding of the endometrium during the menstrual phase?
-Low levels of progesterone and estrogen results in the spiral arteries collapsing. endometrial lining becomes ischemic and as result ruptures and sloughs off causing the menstrual bleed.
How long does mesntrual bleeding take to occur?
2-7 days
Describe what occurs during the proliferative phase.
Estrogen are high and endometrium begins to regenerate
1. Thickness of endometrium 3-4mm
2. Glands are increased in number and length, but remain tubular.
3. The stroma cells proliferate and show mitosis.
4. Vascularity is increased, the spinal arteries increased in length and traverse the whole endometrium
Cervical changes occur that make it more hospitable for sperm.
Describe the Secretory phase ?
The corpus luteum (granulosa cells) is producing progesterone.
Progesterone maintains the lining of the endometrium.
Spiral arteries grow longer and uterine glands secrete more mucus
