Podcast
Questions and Answers
What type of contact occurs between the placental villi and maternal blood?
What type of contact occurs between the placental villi and maternal blood?
Which of the following is NOT produced by the placenta?
Which of the following is NOT produced by the placenta?
What is the average diameter of a term placenta?
What is the average diameter of a term placenta?
What covers the chorionic plate on the fetal side of the placenta?
What covers the chorionic plate on the fetal side of the placenta?
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How many operational units termed placentomes can be found in the human placenta?
How many operational units termed placentomes can be found in the human placenta?
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Which statement accurately describes the yolk sac and amnion during pregnancy?
Which statement accurately describes the yolk sac and amnion during pregnancy?
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What happens to the decidua during pregnancy?
What happens to the decidua during pregnancy?
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What are the two parts that make up the placenta?
What are the two parts that make up the placenta?
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How do cytotrophoblast cells contribute to the implantation process?
How do cytotrophoblast cells contribute to the implantation process?
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What defines the three areas of the decidua?
What defines the three areas of the decidua?
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What is the role of extravillous trophoblasts during early pregnancy?
What is the role of extravillous trophoblasts during early pregnancy?
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When do the lacunae surrounding the villi turn into the intervillous space filled with maternal blood?
When do the lacunae surrounding the villi turn into the intervillous space filled with maternal blood?
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What type of villi is present by day 20-21 of gestation?
What type of villi is present by day 20-21 of gestation?
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What is primarily found in the intervillous space before 12 weeks of gestation?
What is primarily found in the intervillous space before 12 weeks of gestation?
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Which component does the trophoblast cooperate with to develop into the basal plate?
Which component does the trophoblast cooperate with to develop into the basal plate?
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Study Notes
Pregnancy Overview
- Presented by Dr. Bushra M. Jarallah, Obstetrician/Gynecologist
- Medical school teacher at the University of Garmian
- 2024-2025 academic year
Embryonic Implantation, Decidua & Placenta
- Fertilization produces a zygote that undergoes mitotic cleavages as it moves to the uterus, forming blastomeres which develop into a morula
- No growth during cell cleavage, blastomeres get smaller, and the morula is similar in size to the initial oocyte
- About 5 days after fertilization, the embryo enters the uterine cavity
- Blastomeres arrange to form a blastocyst, comprising a trophoblast layer (outer cells) and an embryoblast/inner cell mass (inner cells)
- The blastocyst remains in the uterine lumen for 2 days, immersed in endometrial gland secretions on the mucosa
- Implantation, or nidation, involves blastocyst attachment and proteolytic penetration of the endometrium, lasting approximately 3 days
- During implantation, embryoblast cells rearrange to form the amnion and yolk sac
- The bilaminar embryonic disc develops, with the epiblast layer continuous to the amnion and the hypoblast layer continuous with the yolk sac
- The embryo develops completely from this initial embryonic disc
Placenta
- The site for nutrient, waste, oxygen, and carbon dioxide exchange between the mother and the fetus
- Consists of two main parts: chorion (embryonic) and decidua basalis (maternal)
- Maternal blood vessels within the placenta placental villi are in direct contact with maternal blood; no intervening layer
- Exchange occurs between embryonic blood and maternal blood in lacunae of the basalis
- By the end of the first trimester, the placenta is complete, with thousands of tertiary chorionic villi for extensive metabolite exchange
- The placenta produces hormones, like human chorionic gonadotropin (hCG), lactogen, relaxin, and various growth factors, in addition to estrogen and progesterone
- Term placenta average diameter: 22 cm
- Central thickness: 2.5 cm
- Weight: 450-500 g
Placental Development
- Trophoblast lineage starts early in development, with the transition from morula to blastocyst, differentiation begins.
- Trophoblast is the first layer to differentiate
- At this stage of development, there is creation of outer layer of fused trophoblast cells termed the outer syncytiotrophoblast
- This outer layer interacts with maternal tissues
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Description
Test your knowledge on the structure and function of the human placenta with this quiz! Explore key concepts such as placental villi, decidua, and the roles of various cells during pregnancy. Perfect for students and anyone interested in human biology.
