Implantation and Placenta Flashcards
(116 cards)
1
Q
Implantation is the interactive process between the ____ and _____ that results in its hatching, attaching, adherence, invasion and inclusion within the _____
A
Blastocyst and endometrial epithelium; uterine wall
2
Q
_____ is the earliest stage of gestation.
A
Implantation
3
Q
Implantation is also referred to as ________.
A
Nidation
4
Q
Implantation is the process by which the ____ gets attached, embedded and included within the uterine wall
A
Blastocyst
5
Q
Implantation begins on the ________ day after fertilization.
A
6th
6
Q
Implantation occurs through the end of which week after fertilization?
A
1st week
7
Q
The blastocyst attaches to the ______ usually adjacent to ______
A
Endometrial epithelium; Embryonic pole
8
Q
Trophoblast proliferates rapidly and differentiates into which two layers?
A
Cytotrophoblast and Syncytiotrophoblast
9
Q
Mononucleated inner cellular layer describe which trophoblast layer?
A
Cytotrophoblast
10
Q
Multinucleated protoplasm with no cell boundaries describe which trophoblast layer?
A
Syncytiotrophoblast
11
Q
Finger-like processes of which trophoblastic layer extend through the endometrium and invade the endometrial connective tissue?
A
Syncytiotrophoblast
12
Q
By the end of the 7th day, the blastocyst is implanted in ______ layer of the endometrium and derives its nourishment from _____
A
Superficial compact layer; the eroded endometrium
13
Q
By the 10th day, the blastocyst is completely buried within which layer(s) of the endometrium?
A
Functional layer: Stratum compactum and stratum spongiosum
14
Q
The defect in endometrial epithelium at implantation site is closed by _____ by _____ day
A
Closing plug; 10th day
15
Q
The defect in the endometrial epithelium gradually disappears by day _____ due to ______
A
Days 12 and 13; Proliferation of surrounding cells
16
Q
By the end of _______ week, the blastocyst is completely embedded and the surface defect in the mucosa has healed.
A
2nd week
17
Q
What circulatory system begins after complete implantation by the end of 2nd week?
A
Uteroplacental circulation
18
Q
Before uteroplacental circulation, the embryo derive its nutrients from ______ and _____
A
From primitive yolk sac and uterine glandular secretions
19
Q
What phrase summarizes the developmental events of the 2nd week?
A
The Week of Two’s
20
Q
In the 2nd week, trophoblast differentiates into?
A
Cytotrophoblast and Syncytiotrophoblast
21
Q
In the 2nd week, embryoblast differentiates into?
A
Epiblast and Hypoblast
22
Q
In the 2nd week, extraembryonic mesoderm differentiates into?
A
Somatopleuric and Splanchnopleuric mesoderm
23
Q
In the 2nd week, the blastocyst cavity differentiates into?
A
Amniotic and yolk sac cavities
24
Q
Small cavities called lacunae appear in the _______ during implantation.
A
syncytiotrophoblast
25
Lacunae expand, get filled with maternal blood and establish ______
Primitive uteroplacental circulation
26
Primitive uteroplacental circulation is established by what structures in the syncytiotrophoblast?
Lacunae
27
Major changes during implantation occur due to increase in _____ and ______ between fetal and maternal components.
Nutritional exchange and surface area
28
List the four main stages of implantation in order.
Migration/hatching, Adplantation, Apposition, Invasion (MAdAI)
29
Blastocyst release from zona pellucida is known as?
Migration or hatching
30
The entry of blastocyst into the uterine stroma is called?
Invasion
31
The first loose contact between blastocyst and endometrium is termed?
Apposition
32
When the blastocyst aligns with the inner cell mass close to the endometrial epithelium, this is called?
Adplantation
33
Placental development: what is formed in week 2 and how?
Primary villi; Trophoblastic shell cells form fingerlike extensions into maternal decidual basalis
34
Placental development: what is formed in week 3 and how?
Secondary villi; Extraembryonic mesoderm grows into and covers the entire surface of the chorionic sac
35
Placental development: what is formed in week 4 and how?
Tertiary villi; Mesenchyme differentiate to blood vessel and cells fuse with placental vessels
36
______ forms fingerlike extensions into maternal ______ during week 2 of placental development (first stage of chorionic villi development).
Trophoblastic shell cells; decidual basalis
37
_______ grows into and covers the entire surface of the ______ in week 3 of placental development (second stage of chorionic villi development).
Extraembryonic mesoderm; chorionic sac
38
______ differentiates into _____ and cells fuses with _______ in week 4 of placental development (third stage of chorionic villi development)
Mesenchyme differentiates into blood vessels; placental vessels
39
What is the fetal part of the placenta?
Villous chorion
40
What is the maternal part of the placenta?
Decidual basalis
41
The placenta is continuous with which sacs?
Amniotic and chorionic sacs
42
What is the shape, average diameter, average thickness, average weight of the placenta at birth?
discoid; 20 cm; 3cm; 500-600 grams
43
The weight of the placenta is approximately what fraction of the fetal birth weight?
1/6 – 1/7
44
Name three variants of placental shape.
Accessory bidiscoid, diffuse, horse-shoe
45
What structure gives a cobblestone appearance on the maternal side of the placenta and it is covered with _____?
Cotyledons; covered with decidual basalis
46
What part of the chorion is smooth and lacks villi?
Chorion laeve
47
Maternal blood enters which space in the placenta?
Intervillous space
48
Fetal blood circulates through which vessels in the placenta?
Fetal capillaries
49
What attaches to the chorionic plate on the fetal surface of the placenta and it is covered with _____?
Umbilical cord; covered with amniotic membrane
50
What is the diameter, length range and average length of the umbilical cord?
1–2 cm diameter; 30-90cm long; 50cm average length
51
Four descriptions of the appearance of the umbilical cord on the fetal surface of the placenta.
Shiny, grey, soft, coiled, compressible
52
_____ connects fetus with placenta
Umbilical cord
53
List three contents of the umbilical cord.
1 vein, 2 arteries, Wharton's jelly
54
What is considered an extremely short and extremely long umbilical cord?
5 cm = extremely short; 150cm = extremely long
55
Three bases of placental classification.
histology, structural organization, layers between feto-maternal circulation
56
Three classifications of placenta based on histology, structural organization and layers between feto-maternal circulation.
Hemochorial, Endotheliochorial, Epitheliochorial
57
______ placentation features direct contact between chorion and maternal blood.
Hemochorial
58
In ______ placentation, maternal endometrial blood vessels are bare to endothelium in contact with chorion.
Endotheliochorial
59
In _____ placentation, maternal epithelium of the uterus is in contact with primitive chorion.
Epitheliochorial
60
Which species have a hemochorial placenta?
Humans
61
Name animals that have an endotheliochorial placenta.
Dog, cat
62
Name two animals with epitheliochorial placentas.
Pigs and cows
63
In hemochorial placenta, _____ is in direct contact with _____
Chorion in direct contact with maternal blood
64
In endotheliochorial placenta, ______ are bare to ______ in contact with ______
maternal endometrial blood vessels; endothelium; chorion
65
In epitheliochorial placental, ______ is in contact with ______
Maternal epithelium of the uterus; primitive chorion
66
List four types of placenta
Discoid, Zonary, Diffuse, Cotyledonary
67
Five animals with discoid placenta
Humans, monkeys, rabbit, rat, mice
68
Four animals with zonary placenta
Dogs, cat, bear, seal
69
Six animals with diffuse placenta
Horse, kangaroo, pig, camel, lemur, whale
70
Four animals with cotyledonary placenta
Cow, deer, goat, giraffe
71
The type of placenta in humans is ____
discoid
72
What are the six types of placenta in humans (discoid)?
Circummarginate/Circumvallate, Succenturiate lobe, Bipartite, Placenta fenestra, Placenta membranacae, Placenta praevia
73
What placental variant in humans has a double fold of chorion and amnion whitish ring with fibrin in between?
Circummarginate/Circumvallate placenta
74
Which placental type in humans features an accessory cotyledon?
Succenturiate lobe placenta
75
What is a bipartite placenta?
Placenta with two separate lobes
76
Avascular window in succenturiate variant is seen in which human placenta type?
Placenta fenestra
77
What characterizes placenta membranacae?
Vascularised decidual capsularis
78
What is placenta praevia?
Placenta located in lower uterine segment
79
In placental blood vessels, arteries are ____ and carry ____ blood from the ____ into the ____
Paired; deoxygenated blood; placenta; placental villi
80
In placental blood vessels, veins are initially ____, then _____ at _____ (period?).
paired; singled; end of embryonic period
81
Umbilical veins (placental blood vessels) carry ____ blood to the embryo via _____
oxygenated blood; sinus venosus
82
What are the two types of placental nutrition?
Histiotrophic and hemotrophic
83
Which type of nutrition occurs early in placental development and is involved in initial transfer of nutrients from mother to fetus?
Histiotrophic nutrition
84
Which type of placental nutrition is blood-borne and occurs later?
Hemotrophic nutrition
85
What separates maternal blood in the intervillous space from fetal blood in the placenta?
Chorionic derivative
86
Placental barrier is a _____ barrier and ____ membrane
pseudo; selectively permeable
87
In utero, fetomaternal blood can mix. T or F
False
88
List the four layers of the placental barrier that separate mother and fetus blood.
Cytotrophoblast, Syncytiotrophoblast, Villous core connective tissue, Fetal capillary endothelium
89
What are the two components of the placenta by the 4th month?
Fetal portion (chorionic frondosum), Maternal portion (decidual basalis)
90
Do most maternal hormones cross the placenta?
No
91
Name three maternal hormones that do not cross the placenta.
Thyroxine, progestins, synthetic estrogens
92
Name seven viruses that easily cross the placental barrier.
Rubella, Cytomegalovirus, Coxsackie, Variolla, Varicella, Measles, Poliomyelitis
93
Drugs and their metabolites traverse the placental barrier readily to cause ____
Serious congenital malformations
94
What maternal substances have been linked to habituation?
Cocaine and heroin
95
What are the four major functions of the placenta?
Hormone production, Nutrients and electrolyte exchange, Gaseous exchange, Transmission of immunoglobulins
96
Which fetal membrane is involved in blood-gas exchange with maternal blood?
Chorionic villi
97
In ____ months, decidua forms _____ which project into ____ but do not reach _____
4-5 months; decidual septa; intervillous spaces; chorionic plate
98
Do decidual septa reach the chorionic plate?
No, they do not
99
Decidual septa have core of _____ but their surfaces are covered by ______
Maternal tissue; Syncytial cells (syncytiotrophoblasts)
100
What separates maternal blood in intervillous lakes from fetal tissue?
Syncytial layer on decidual septa
101
What does the formation of decidual septa lead to structurally?
Division of the placenta into cotyledons
102
_____ and _____ enlarges the placenta in a ____ fashion with the former structures throughout the pregnancy
Continuous fetal and uterine growth; parallel
103
How much of the maternal surface of the uterus does the placenta cover?
15–30%
104
What causes the increase in placental thickness?
Arborisation (branching) of existing villi
105
Attachment of the umbilical cord is usually _____ but occasionally _____ and rarely ____
eccentric; marginal; velamentous
106
How much blood is present in the intervillous space of a mature placenta and how often is the blood replenished?
Approximately 150 ml; 3–4 times per minute
107
What is the surface area of chorionic villi in a mature placenta?
4–14 m²
108
What increases the surface area of the intervillous space and thus increase the exchange rate between maternal and fetal circulation?
Microvilli on chorionic villi
109
Where does normal implantation of the placenta occur?
Upper part of uterine body, more often on the posterior wall
110
______ determines placenta localization.
Implantation site
111
What is the consequence of implantation in the lower uterine segment?
Placenta previa
112
The two major abnormal implantation sites are:
Uterine (lower segment of the uterus), Extrauterine (fallopian tube, ovary, abdominal cavity)
113
Name three sites of extrauterine (ectopic) implantation.
Fallopian tube, ovary, abdominal cavity
114
By the end of the _______ day, the blastocyst is implanted in superficial compact layer of the endometrium
7th day
115
By the _____ day, the blastocyst is completely buried within the functional layer (Stratum compactum and stratum spongiosum) of the endometrium
10th day
116
Hatching of the blastocyst involves the removal of what structure?
Zona pellucida
