Physiology Of Menstrual Cycle Flashcards
Overview
(6)
1-21 to 35,mean 28 d
2- 3 to 7 days, mean 5d
3- 30 to 50 ml/ cycle
4-400 cycles
5-irregular cycles in the first years and prior to menopause
6-It’s a synchronization between hypothalamus, pituitary gland, uterus, ovaries, vagina, and cervix.
Talk about hypothalmic releasing hormones
1-peptides
2-short half-life due to fast degradation
3-undetectable
4- secreted in a palsatile manner
What are they ( hypthalamic releasing h)
1- gnrh
2- trh
3- crh
4- ghrh
5- pih or dopamine
Talk about gnrh
(6)
1-Decapeptide
2- short half-life because of fast degradation
3-undetectable
4-secreted in a pulsatile manner
5- At first, it’s suppressed, then released in a pulsatile manner, starting the onset of puberty 6-Responsible for synthesis of pituitary gonadotropins FSH and LH.
Talk about pit ant , post
Anterior Pituitary, (Adenohypophysis)
1-FSH
2- LH from gonadotrophs
3-TSH from thyrotrophs
4- ACTH from adrenocorticotrophs
5-GH from somatotrophs
6-Prolactin from lactotrophs
Posterior Pituitary, (Neurohypophysis)
ADH, and Oxytocin.
Talk about fsh , lh
(5)
1-Glycoprotein
2- detectable
3- Fsh,LH at day 2 to 5
-level :
• 5:10~> (n)
• 10:20 ~>( slight + due to - e2)
• +20 ~> menopause
-FSH higher than LH
4- LH only at day 14
5- Similarity in the anterior pituitary hormones in alpha subunit, so beta subunit is required.
Nature of follicles in ovaries
(4)
1-At fetal life 7 million
2- at birth 1.5 to 2 million
3- at puberty 400,000
4- 400 cycles while depletion of others.
Talk about follicular phase
1- From menses to ovulation, 14 days
2- in which FSH stimulates the growth and maturation of pre-mordial follicles to secrete E2 that causes proliferative phase in endometrium.
Talk about primordial follicles
-Single oocyte that is arrested in meiosis 1, pro phase, diplotene stage, with a single layer of granulosa cells surrounded by a single layer of theca cells.
Talk about preantral follicles
-FSH stimulates growth of pre-mordial follicles, causing :-
-growth of oocytes
-transferring the one layer of granulosa cells to a multi-layer, forming pre-antral follicles.
Talk about two cell theory
- Theca cells : under LH influence
cholesterol ~> androstenedione, then transport to granulosa cells.
-Granulosa cells : under FSH influence,
androstenedione ~> E2 by aromatization
Products
-E2
-androgen
E2 : Increases FSH receptors on granulosa cells, and along with FSH, they increase LH receptors
Ando :Low-level inhibits aromatization, high-level inhibits aromatization and causes follicular atresia.
-Other factors
*inhibin :
-peptide from granulosa cells
-inhibit FSH and enhance LH-induced androgen production, inhibiting aromatization and causing follicular atresia, thus the dominant follicle can continue
*Activin :
-peptide from granulosa cells
- the opposite of inhibin
*Growth factor, insulin-like growth factor, fibroblast growth factor, epidermal growth factor, enhance FSH.
Selection of dominant follicle
(5)
1-The highest FSH receptors
2-the highest FSH-induced LH receptors
3-the highest aromatization activity
4-the highest in E2 and inhibin
5- the least requiring FSH and LH to complete follicular maturation.
Talk about preovulatory follicles ( matue graafin follicles)
-FSH stimulates pre-antral follicles, causing the oocyte to be aside, secreting gletanous material, forming zona bellicita.
-Theca cells are transformed into interna theca and externa theca.
Talk about ovulation
1-FSH continue to increase E2 and LH-induced receptors on granulosa cells of the dominant cell ( بيهيء الوضع لlh )
2-When E2 increases peakly, it has positive feedback on LH, causing LH surge.
3- ovulation imoccurs after 12 hours from the peak of LH surge or 36 from the onset of the LH surge.
4-Resumption of oocyte from prophase 1 to meta phase 2 until fertilization occurs to complete meiosis 2 and be mature ovum.
Talk about luteal phase
(4)
1-From ovulation to menstruation 14 days
2-the granulosa cells from the ruptured dominant follicle undergoes luteinization, transforming into corpus luteum under LH influence
3-secretes big amount of progesterone, small amount of estrogen, and inhibin, (dominant follicle in the past)to inhibit FSH and LH from follicular maturation during luteal phase
4-progesterone enters the endometrium to secretory phase.
Fate of corpus luteam
The uterine phase is 14 days, 5 of them is menses, so lifespan of CL is 9 days
1- (4)
If there is no pregnancy, corpus luteam is dead , ( no LH)
-undergoes luteolysis
-replaced by avascular corpus albicans
-decline of progesterone
-gonadotropin inhibition is released, causing FSH and LH to increase, beginning a new cycle
2- If there is pregnancy, b-HCG forces the corpus luteum, to secrete progesterone, until placental steroidogenesis, occurs during 8th week.
Negative, positive feedbackbacks
-E2, negative with FSH, positive with LH
-prg negative with LH.
Talk about proliferative phase
(4)
1-Meeting follicular phase
2- Menses + proliferative phase
3- E2 causing stromal and glandular growth
4-Transforming one layer of glands with low columnar cells into pseudosterified columnar cells with high mitotic activity and Stromal expansion ~> Increasing the thickness of the endometrium from 0,5 mm after menstruation to 8-12 mm at the end of proliferative phase
Talk about secretory phase
(4)
1-Meeting luteal phase
2-Progesterone is the upper hand hormone
3- Stimulating secretory activity
4- (4)
- Inhibiting estrogen proliferation, thus restricting the thickness of endometrium
-Increasing tortuosity of glands and spiral arteries to fit in the endometrium
-Massive irreversible secretory effect on stroma ( decidualization ) causing nuclear enlargement with high mitotic activity
- at the end ,Endometrium is of 3 portions
- Basal portion(basalis) :
~25% of all endometrium
-Restored in menstruation as it is important for regeneration of all endometrium layers
~Undergoes few changes during menstrual cycle - Intermediate portion( Spongiosum ): Edematous stroma ,Tortuous glands and spiral arteries with secretions
- Superficial portion (Compactum): Desitualized stromal cells
Talk about menstruation
(5)
1-Decline of prg/ E2 due to death of corpus luteum
2-Coiling and vasoconstriction of spiral arteries
3- ischemia of functional portion, (intermedial and superficial)
4-Vasoconstriction is also done by pgf2a ,endothelin-1, platelet activating factor ( paf )
5- Two days from menstruation, FSH and LH begins a new cycle, (follicular phase)
Cervical changes
1- Follicular phase, ( estrogen)
~profuse
~decreased viscosity(thin watery)
~ decreased leukocytes
~+ ferining test, (arborization test) due to high nutrients, NACL, and K, as a result of high E2
~+ spinebarkeit (stretchability ) test ( 7-10 cm)
2-luteal phase(, progesterone)
~scanty
~increased viscosity
~high leukocytes
~ - ferning test
~ -spinebarkeit (stretchability) tests.
Vaginal changes
By Endometrial cytology and maturation index
- follicular phase (estrogen)
Low leukocytes,
0, 30, 70,
-Luteal phase( prg)
-high leukocytes
- 0, 70, 30.
Talk about estro , prg
- Steroids
-detectable - e2: early at the follicular phase
- prg : at day 21, must be above 5 to indicate ovulation.
