p.20
Placental Anomalies and Variations
What characterizes placenta accreta?
Chorionic villi extend to the myometrium.
p.3
Embryonic Development Stages
What forms the chorioallantoic membrane?
The fusion of the Allantois and Chorion.
How long does the implantation process continue?
Through the second week of development.
p.15
Chorion and Chorionic Villi Development
What happens to chorionic villi until the beginning of the 8th week?
They surround the whole chorionic sac and then differentiate.
p.18
Placental Membrane Composition
How does the placental membrane change after the 20th week?
It becomes more permeable and is formed of two layers.
p.13
Chorion and Chorionic Villi Development
What hormone does the syncytiotrophoblast secrete?
HCG (Human Chorionic Gonadotropin).
p.3
Embryonic Development Stages
What are the functions of the Amnion?
Nutrients, gas exchange, immunity, waste removal.
p.19
Placental Anomalies and Variations
Where do chorionic villi normally persist?
Only at the site of decidual basalis.
p.11
Decidual Reaction and Formation
What causes the enlargement of connective tissue cells in the decidual reaction?
Accumulation of lipid and glycogen.
p.7
Uterine Adaptations for Pregnancy
What is the process that prepares the uterus for implantation?
Adaptation of the uterus, including predecidualization and decidualization.
p.8
Uterine Adaptations for Pregnancy
What happens to the endometrium during predecidualization?
It increases in thickness, becomes vascularized, and its glands coil and increase their secretions.
p.14
Chorion and Chorionic Villi Development
What characterizes the secondary chorionic villi?
Extraembryonic mesoderm extends inside the villi, occurring early in the 3rd week.
p.7
Uterine Adaptations for Pregnancy
What changes occur in the endometrium during decidualization?
Accumulation of lipid and glycogen.
p.13
Chorion and Chorionic Villi Development
What happens to the trophoblast during implantation?
It thickens at the region of contact with the endometrium and differentiates.
p.17
Placental Circulation Mechanism
Through which vessels does poorly oxygenated blood travel from the fetus to the placenta?
Through the two umbilical arteries.
p.2
Components of the Placenta
What are the two components of the placenta?
Fetal part and maternal part.
p.8
Uterine Adaptations for Pregnancy
What are the two zones formed by the luminal and basalolateral cells in the endometrium?
Zona compacta (luminal cells) and zona spongiosa (basalolateral cells).
p.16
Placenta Structure and Function
Describe the fetal surface of the placenta.
Smooth, transparent, covered by amnion with umbilical cord attached near its center and umbilical vessels radiating from it.
p.14
Chorion and Chorionic Villi Development
What are the primary chorionic villi?
Finger-like processes formed of outer syncytiotrophoblast and inner cytotrophoblast that appear at the end of the 2nd week.
p.12
Decidual Reaction and Formation
What is the decidua basalis?
The part of the endometrium at the site of implantation that forms the maternal part of the placenta.
p.1
Placental Circulation Mechanism
What is the role of the placenta and umbilical cord?
They serve as a transport system for substances between the mother and the fetus.
p.8
Uterine Adaptations for Pregnancy
When do decidual cells cover the endometrium toward the uterine cavity?
About 9 to 10 days after ovulation.
p.17
Placental Circulation Mechanism
Where does the exchange of materials between fetal and maternal blood occur?
In the intervillous spaces.
p.5
Embryonic Development Stages
What is the process of cleavage in the zygote?
Multiplication of total cell number with simultaneous reduction of their size.
p.19
Placental Anomalies and Variations
What is placenta membranacea?
A rare and abnormal variation of placental development where the placenta covers a larger area of the uterine wall than in a typical pregnancy.
p.14
Chorion and Chorionic Villi Development
What happens during the tertiary stage of chorionic villi development?
Arterioles, venules, and capillaries develop in the mesenchyme of villi and join umbilical vessels during the 3rd week.
p.18
Placental Membrane Composition
What is the primary function of the placental membrane?
To separate fetal blood from maternal blood.
p.12
Decidual Reaction and Formation
What is the function of the decidua parietalis?
It lines the rest of the endometrium in the body and fundus.
p.14
Chorion and Chorionic Villi Development
When does embryonic blood begin to flow through capillaries in chorionic villi?
By the end of the 3rd week.
p.13
Chorion and Chorionic Villi Development
What is a characteristic of the syncytiotrophoblast?
It contains multiple nuclei in a common cytoplasm with no cell boundaries.
p.3
Embryonic Development Stages
When does the Amnion form post-fertilization?
10 days post-fertilization.
p.21
Placental Anomalies and Variations
What is Battledore placenta?
A condition where the umbilical cord is attached to the margin of the placenta.
p.1
Components of the Placenta
What are the two components of the placenta?
Fetal part (from the chorionic sac) and maternal part (from the endometrium).
p.19
Placental Anomalies and Variations
What characterizes an accessory placenta?
A patch of chorionic villi that persists a short distance from the main placenta, which is smaller and less developed.
p.8
Uterine Adaptations for Pregnancy
When do the changes in the endometrium reach their maximum after ovulation?
About 7 days after ovulation.
p.16
Placenta Structure and Function
What is the average weight of the placenta?
About one-sixth that of the fetus (500 - 600 gm).
p.8
Uterine Adaptations for Pregnancy
What type of cells are produced on the surface of the endometrium during predecidualization?
Decidual cells (rounded cells).
What happens by the end of the second week of development?
The whole blastocyst is embedded in the endometrium.
p.2
Placenta Structure and Function
What role do the placenta and umbilical cord serve?
They act as a transport system for substances between the mother and the fetus.
p.3
Embryonic Development Stages
What does the Allantois derive from?
A diverticulum from the hindgut.
p.11
Decidual Reaction and Formation
What happens to the endometrium during the decidual reaction?
It becomes thicker and more vascular.
p.21
Placental Anomalies and Variations
What is velamentous insertion of the cord?
A condition where the umbilical cord is attached to the membranes surrounding the placenta, making umbilical vessels liable to rupture.
What is the process of implantation?
The attachment and invasion of the uterus endometrium by the blastocyst (trophoblast).
p.3
Embryonic Development Stages
What do the three germ layers give rise to?
The four extraembryonic membranes that surround the developing embryo.
Where does the human blastocyst implant in the uterus?
Along the anterior or posterior wall of the body of the uterus.
p.7
Uterine Adaptations for Pregnancy
What is the role of the trophoblast in the implantation process?
It interacts with the decidualized endometrium.
p.17
Placental Circulation Mechanism
What do the umbilical arteries divide into?
Several chorionic arteries.
p.20
Placental Anomalies and Variations
What is placenta percreta?
A condition where chorionic villi penetrate the whole thickness of the myometrium and extend to the perimetrium.
p.17
Placental Circulation Mechanism
What network is formed in the chorionic villi?
An arterio-capillary-venous network.
p.18
Placental Membrane Composition
What are the two layers of the placental membrane after the 20th week?
1. Syncytiotrophoblast 2. Endothelium of fetal blood vessels.
p.3
Embryonic Development Stages
What is the significance of the umbilical cord in relation to the Allantois?
It is associated with the Allantois.
p.10
Decidual Reaction and Formation
What is the decidua?
The functional layer of the endometrium of the gravid (pregnant) uterus.
p.4
Embryonic Development Stages
What is the initial stage of placentation?
The two-cell zygote undergoes mitotic divisions.
p.3
Embryonic Development Stages
What is the Chorion derived from?
The outer trophoblastic layer.
p.3
Embryonic Development Stages
What is the role of the Yolk sac?
Haematopoiesis and early nutrient and gas exchange.
p.11
Decidual Reaction and Formation
What occurs to the endometrial glands during the decidual reaction?
They become full of secretion.
p.10
Decidual Reaction and Formation
Which parts of the uterus are included in the decidua?
The endometrium of the fundus and body of the uterus.
p.9
Decidual Reaction and Formation
What develops further during decidualization?
Uterine glands, zona compacta, and epithelium of decidual cells.
p.4
Embryonic Development Stages
What are the stages of the embryo during early development?
2 cell, 4 cell, and 8 cell stages.
p.20
Placental Anomalies and Variations
What is placenta previa?
A condition where the blastocyst implants close to or overlying the internal os of the uterus, leading to late pregnancy bleeding.
p.7
Uterine Adaptations for Pregnancy
Which parts of the uterus are involved in the adaptation for implantation?
Fundus and body of the uterus.
p.18
Placental Membrane Composition
What are the four layers of the placental membrane until the 20th week?
1. Syncytiotrophoblast 2. Cytotrophoblast 3. Extraembryonic mesoderm 4. Endothelium of fetal blood vessels.
p.16
Placenta Structure and Function
Describe the maternal surface of the placenta.
Irregular, divided into convex areas called cotyledons.
p.15
Chorion and Chorionic Villi Development
What happens to the villi in contact with the decidua capsularis?
They degenerate and become avascular due to compression and disappearance of the decidua capsularis.
