Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Embryology > Bilaminar Embryo (week 2) > Flashcards

Bilaminar Embryo (week 2) Flashcards

1
Q

what are the two forms of trophoblast during week 2 (bilaminar embryo)

A

Trophoblast: cytotrophoblast & syncytiotrophoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the two blastocoele transformations during week 2 (bilaminar embryo)

A

Blastocoele transformations: to primary yolk sac & to secondary yolk sac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the two cavities that form during week 2 (bilaminar embryo)

A

Cavities: Amniotic & chorionic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what placental (chorionic) villi are formed during week 2 (bilaminar embro)?

A

Chorionic Villi (placental): primary & secondary villi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

which pole (dorsal or ventral) invades the endometrium first?

A

dorsal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how many days after fertilization does implantation occur? what are the two stages of implantation?

A

occurs 6-8 days after fertilization; 2 stages = attachment and invasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the two stages of attachment?

A
  1. apposition

2. adhesion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens during the apposition stage of attachment?

A

it is the first stage of attachment; the blastocyst forms an unstable interaction with the uterine wall via interdigitation between pinopodes (uterine epithelium) and microvilli (blastocyst surface)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

During apposition, the blastocyst forms an unstable interaction with the uterine wall via ________ on the uterine epithelium and __________ on the blastocyst

A

pinopodes (uterine epithelium); microvilli (on the blastocyst)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens during the adhesion stage of attachment?

A

second stage of attachment; increased physical contact between the animal pole of the blastocyst and the uterine epithelium (more stable binding) via specific integrin receptors and components of the ECM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what facilitates the more stable attachment of the blastocyst to the uterine epithelium during adhesion stage?

A

specific integrin receptor that bind to extracellular matrix components that are produced by trophoblast and the uterine wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

During Invasion, the trophoblast cells differentiate into mononuclear ______ and mulitnuclear ________.

A

cytotrophoblast and synctiotrophonblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what penetrates through the uterine eptithelium first, synctiotrophoblast or cytotrophoblast?

A

synctiotrophoblast first, followed by cytotrophoblast and the rest of the blastocyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what facilitates the penetration of the blastocyst through the uterine epithelium and into the endometrium? how?

A

the synctiotrophoblast secretes matrix metalloproteinase (MMPs) which degrade components of the basement membrane and EXM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what generally occurs during invasion?

A
  1. Synctotrophoblast penetrates uterine epithelium preceded by retraction of epithelium cells
  2. Synctotrophoblast breaches the basement membrane
  3. Invasion of endometrium by Synctotrophoblast (via release of MMPs) followed by the rest of blastocyst
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what happens to the embryoblast cells as soon as the blastocyst begins to invade the endometrium?

A

the embryoblast cells (inner cell mass) begin to proliferate and differentiate, separating into two distinct layers: hypoblast and epiblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what two cell layers does the embryoblast divide into? What are their respective locations

A

hypoblast– cell layer facing blastocyst cavity

epiblast – cell layer adjacent to the trophoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the amnionic cavity formed by?

A

cavitation of the epiblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what cells line the amnionic cavity on the side adjacent to the hypoblast?

A

epiblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what cells line the amnionic cavity on the side adjacent to the trophoblast?

A

aminoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the bilaminar embryo?

A

2 adjacent flat disks formed by the epiblast and hypoblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what does the trophoblast give rise to?

A

nothing! it is terminally differentiated tissue (cant turn into anything else but trophoblast cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the inner cell mass give rise to?

A

everything! it is pluripotent and splits into the hypoblast and epiblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what do the hypoblast and amnioblast cells give rise to?

A

only extraembryonic tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what do the epiblasts give rise to?

A

all tissues and organs of the embryo

26
Q

What cells gives rise to the exocoelomic (Heuser) membrane?

A

hypoblast cells

27
Q

what lines the primitive yolk sac?

A

exocoelomic (Heuser) membrane

28
Q

What is the extraembryonic mesoderm formed by?

A

hypoblast cells that migrated into the space between the Heuser membrane and trophoblast and they transdifferntiated into mesenchymal cells

29
Q

what are extraembryonic coelom? where are they found? what is its function?

A

aka “chorionic cavity” ;
lacunae that form within the extraembryonic mesoderm and that gradually become larger; function is to split the extraembryonic mesoderm into two layers (splanchnopleuric and somatopleuric)

30
Q

what are the two layers of the extraembryonic mesoderm? what does each layer cover?

A
  1. splanchnopleuric mesoderm (covers the yolk sac)

2. somatopleuric mesoderm (lines the trophoblast and amnionic cavity)

31
Q

What is the external lining of the primitive yolk sac? the internal lining?

A

external: extraembryonic mesoderm
internal: Heuser’s membrane

32
Q

What forms from the second wave of proliferating and differentiating hypoblast cells?

A

extraembryonic endoderm; displacing the primitive yolk sac and form a much smaller secondary/definitive yolk sac

33
Q

what do the remnants of the primitive yolk sac become?

A

exocoelomic cysts

34
Q

what is the internal lining of the secondary yolk sac? what is the external lining?

A

internal: extraembryonic endoderm (second wave hypoblast)
external: splanchnopleuric mesoderm

35
Q

what forms the chorionic plate?

A

somaptopleuric mesoderm with adjacent cytotrophoblast

36
Q

what is the only place where the embryo remains to be attached to the chorionic plate?

A

connecting stalk

37
Q

what is the connecting stalk?

A

a mass of extraembryonic mesoderm that is the only place where embryo remains to be attached to the chorioinic plate

38
Q

why is it necessary that the embryo establish a communication with maternal blood supply?

A

because mammalian embryos require an external source of nutrients to grow and develop

39
Q

How does the embryo begin to establish a communication with maternal blood?

A

the synctiotrophoblast begin to engulf maternal endometrial capillaries and the maternal blood fills the trophoblastic lacunae creating an anastomotic network of blood filled spaces within the synctiotrophoblast. The lacunar blood then comes into contact with the placental (chorionic) villi and provides an interface between the embryo and maternal blood circulation

40
Q

what are the placental (chorionic) villi formed from?

A

cytotrophoblast forming cellular columnar structures and then transforming into 4 diff types of villi

41
Q

what are primary villi characterized by? What day post-fertilization are they usually present?

A

cellular columns of cytotrophoblasts

days 11-13

42
Q

what are secondary villi characterized by? What day post-fertilization are they usually present?

A

primary villi + mesenchymal core

day 16-17

43
Q

what are tertiary villi characterized by? What day post-fertilization are they usually present?

A

secondary villi + blood capillaries that differentiate into blood vessels that connect up with embryonic blood vessels later in development
day 21

44
Q

when is the primitive placenta established?

A

by the end of the third week of gestation (with the formation of the tertiary villi)

45
Q

What is an early spontaneous abortion (ESA)?

A

a pregnancy that is lost during the first 3 weeks after fertilization ; random and usually represents natural selection; usually goes undetected

46
Q

what is a recurrent spontaneous abortion (RSA)

A

3+ consecutive pregnancy losses before the 20th week of gestation

47
Q

what is recurrent spontaneous abortion caused by?

A
  1. genetic anomalies
  2. anatomical anomalies
  3. endocrine factors
  4. immunological factors
  5. infections
  6. smoking, alcohol consumption, and other environmental factors
48
Q

What type of genetic anomalies are common in recurrent spontaneous abortion?

A

usually there is a normal karyotype (genome), with triploidy or tetraploidy of sex hormones, or monosomy of X chromosome

49
Q

what is an ectopic pregnancy?

A

pregnancy resulting from embryo implantation outside the normal sites in the uterus (usually in the fallopian tube or peritoneal cavity)

50
Q

what are the main causes of ectopic pregnancy?

A
  1. infection (gonorrhea, chlamydia)
  2. inflammation (pelvic inflammatory disease.. from STDs)
  3. scar tissue from previous abdominal or fallopian surgeries
  4. abnormal fallopian tube development
51
Q

what are the symptoms and treatment of ectopic pregnancy?

A

symptoms: severe abdominal pain in pregnant women, severe internal bleeding
treatment: surgical removal of ectopic embryo

52
Q

What is a complete hydaidiform mole (CHM)

A
  • human conceptus that develops into a disorganized mass of placental derivatives (fetus is absent)
  • 2 sets of chromosomes solely of paternal origin (no expression of maternally expressed imprinted genes)
  • normal embryo cannot develop, but trophoblast can develop, do the fetus does not develop at all and conceptus is comprised solely of the trophoblast
53
Q

where does CHM usually occur? why?

A

in the trophoblast because expression of maternally expressed imprinted genes is not required for trophoblast development and funciton, but both maternal and paternal expressed imprinted genes are necessary for normal embryo development

54
Q

what are imprinted genes?

A

genes that are only expressed from the maternal or paternal copy of the chromosome

55
Q

what is placenta previa?

A

an obstetric complication in which the placenta is inserted partially or wholly in lower uterine segment\
Four stages: I-IV, where I is placenta in lower segment and does not cover the internal os –> complete covering of cervix)

56
Q

What is Recurrent biparental mole (BiCHM)

A

both maternal and paternal chromosomes are present, but no expression of maternally imprinted genes

57
Q

What are some of the symptoms presend with CHM?

A
  1. vaginal bleeding toward the end of the first trimester
  2. ultrasound reveals the absence of a fetus
  3. hCG levels become excessive early in pregnancy
58
Q

What is choriocarcinoma?

A

aggressive cancer that represents a highly vascularized malignant transformation of a trophoblast; characterized by early spread of metastasis to the lungs

59
Q

what are the clinical signs of choriocarcinoma?

A
  1. excessive levels of hCG
  2. vaginal bleeding
  3. chest pain
  4. coughing up blood
  5. shortness of breath
  6. chest x-ray showing multiple infiltrates of various shapes in both lungs
60
Q

How is choriocarcinoma treated?

A

surgical removal; the level of hCG must be checked after the surgery to ensure eradication; or chemotherapy with methotrexate

Embryology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions