Ovarian cycle Ovarian cycle Menstrual cycle Menstrual cycle Placentation Placentation Department of the Histology, Cytology and Department of the Histology, Cytology and Embryology Embryology Tatiana Globa Tatiana Globa State University of Medicine and Pharmacy “Nicolae State University of Medicine and Pharmacy “Nicolae Testemitanu” Testemitanu”
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Proliferative phase: day 4 – day 14 of menstrual cycle
Hormonal control of endometrial changes during the menstrual
cycle:
SECRETORY PHASESECRETORY PHASE
(days 14 – 28 of cycle)
Secretory phase
- under control of progesterone (luteal phase of ovarian cycle
- uterine glands coiled, larger lumens
- secrete glycogen, mucin
Secretory phase: day 14 – 28 of menstrual cycle
Gestational hyperplasiaProliferative: day 9 Secretory: day 15 Secretory: day19
Pregnancy
Hormonal control of endometrial changes during
the menstrual cycle:
MENSTRUAL PHASEMENSTRUAL PHASE
(days 1 – 4 of cycle)
Menstruation
At end of luteal phase of ovarian cycle,Progesterone Spiral arteries to constrict
Menstrual phaseMenstrual phase
- the involution of the corpus luteum results from a decrease in blood levels of steroid hormones, leading to an ischemic phase.
- a reduction in the normal blood supply-causing intermittent ischemia-and the consequent hypoxia determine the necrosis of the functional layer of the endometrium, which sloughs off during the menstrual phase.
Blastocyst
Blastocyst = inner cell mass (embryo) +
outer shell (trophoblast)
Fertilization1
2
3
4
56
7
8
9
Morula
Placenta
Implanted in the wall of the uterus
Composed of fetal portion (chorion) and maternal portion (decidua)
Exchange of gases, nutrients waste products without any mixing of maternal & fetal blood
Functions of placenta
Act as • respiratory organ• excretory organ• nutritive organ• protective organ• endocrine organ (progesterone, estrogens,
human chorionic gonatotropin, melanin spreading factor, other hormones also manufactured by the hypothalamus & pituitary.
This is a circumvallate placenta in which the membranes double back for a short distance over the fetal surface when the chorionic plate is too small. There may be increased fetal loss with this condition.
Decidual cells – glycogen, lipid for early embryonic nourishment; later, produce decidual prolactin (trophic effects on CL), prostaglandins
(prevent immunologic rejection of fetus)of fetus), relaxin (dilates cervix and softens pubic symphysis)
upper portion of decidua (near fetus)
Giant cells: multinucleated, trophoblast derivativesthat migrate into the decidua. Establish cleavage plane for separation of placenta from endometrium after birth.