Early Embryology Flashcards Preview

Anatomy > Early Embryology > Flashcards

Flashcards in Early Embryology Deck (45):
1

Where does fertilization take place?

Ampulla of the uterine tube

2

What processes must sperm undergo to be able to fertilize the egg?

Capacitation and acrosome

3

Female pronucleus

Formed after sperm has entered the egg via meiosis II of the oocyte's nucleus

4

Male pronucleus

Formed by enlargement of the sperm's nucleus

5

When and what is cleavage?

Occurs about 30 hrs post-fertilization, and is the cell division to form the blastocyst

6

Morula

when the cell have reached about 16-32 cells from division

7

What layers does the blastocyst separate into?

Embryo proper (inner cell mass) and Trophoblast (outer cell mass)

8

What portion of the trophoblast penetrates into the endothelium?

Syncyiotrophoblasts

9

Where is the extraembryonic mesoderm and what is it derived from?

Forms between the inner surface of the cytotrophoblast and outer surface of the amnion/exocoelomic membrane, and is derived from the umbilical vesicle

10

How is the chorionic cavity (extraembryonic cavity) formed?

Large cavities form in the extraembryonic mesoderm to form the cavity

11

What 2 layers does the extraembryonic mesoderm form?

Extraembryonic somatic mesoderm and extraembryonic splanchnic mesoderm

12

Hydatidiform Mole

Trophoblast forms placenta membranes, but no embryonic development. Secretes high levels of hCG and may become malignant. Most arise from fertilization of an oocyte with no nucleus

13

Placenta Previa

Placenta forms over the cervix, causing severe and possibly life-threatening bleeding later in pregnancy

14

Placenta percreta

Chorionic villi penetrate the myometrium all the way to the perimetrium

15

Placenta Accrete

Abnormal adherence of placenta to the myometrium

16

Ectopic pregnancy

Implantation of blastocyst outside of the uterus

17

Gastrulation

Process of establishing trilaminar germ disc. Cells slip underneath the epiblast forming the primitive streak

18

3 primary germ layers

ectoderm, mesoderm, endoderm

19

Mesoderm

Forms the paraxial/lateral/intermediate mesoderms

20

Ectoderm

Forms the neuroectoderm and neural crest cells

21

Primitive node

Cephalic end of primitive streak surrounding the primitive pit

22

Nodal gene

establishes the primitive streak, which is the body axis

23

Fate map: Cranial region cells

Turn into notochord

24

Fate map: Intraembryonic mesoderm

turns into Paraxial mesoderm

25

Fate map: Intermediate mesoderm

Turns into lateral plate of mesoderm

26

Fate Map: Extraembryonic mesoderm

Continuous with the lateral mesoderm

27

Growth of embryonic disc

w3: cephalic region broadens and differentiates
w4: caudal region differentiates, primitive streak regresses

28

Embryonic period

w3-8: Organogenesis, cranio/caudal/lateral folding, vasculogenesis

29

Derivates: Ectoderm

CNS, PNS, eyes, epithelial skin, neural plate

30

Derivatives: Paraxial Mesoderm

Bones, tendons, cartilage, muscles, dermis of skin

31

Derivative: Intermediate mesoderm

Urogenital

32

Derivates: lateral mesoderm

Parietal: serous membrane that lines the body cavity
Visceral: membranes around the organs

33

Endoderm

GI and epithelium of the organs

34

When do most large structural defects occur?

Weeks 3-8

35

Holoprosencephaly

aka fetal alcohol syndrome– high doses of EtOH kill the anterior midline, creating craniofacial structure deficiencies

36

Sirenomelia

Caudal region has insufficient mesoderm, impacting lower limb/vertebral/urogential development

37

Situs inversus

Left and right organ positions are switched

38

Sacrococcygeal teratoma

Remnants of the primitive streak proliferate, forming a teratoma on the new borns coccygeal region. Is the most common type of tumor in new borns

39

Weeks 9-12 of fetal development

External genitalia is formed, liver is main site of erythropoiesis

40

Weeks 13-16 of fetal development

Rapid growth, limb movement, face forms, ovaries have oogonia

41

Weeks 17-20 of fetal development

Movements can be felt by mom, CRL size increases another about 50mm

42

Weeks 21-25 of fetal development

Sucking movements begin, fetus reacts to sound, surfactant is beginning to be secreted at 24w

43

Weeks 25-29 of fetal development

Higher survival rate, erythropoiesis switches to the bone marrow

44

Weeks 30-34 of fetal development

Pupillary light reflex, 32+w usually survive

45

Weeks 35-38 of fetal development

CRL:36cm, CHL:50cm, weight:3-3.4kg