Chapter 2: First 8 Weeks of Development

Question 1

Where does fertilization occur?

Answer 1

in the ampulla of the uterine tube

Question 2

Label the image?

Answer 2

Refer to labeled image.

Question 3

What are the 2 changes spermatozoa undergo in the female genital tract prior to fertilization?

Answer 3

capacitation
cortical reaction

Question 4

Capacitation?

Answer 4

removal of several proteins from the plasma membrane of the acrosome of the spermatozoa

Question 5

Cortical reaction.

Answer 5

hydrolytic enzymes are released from the acrosome used by the sperm to penetrate the zona pellucida.

This reaction prevents other spermatozoa from penetrating the zona pellucida thus preventing polyspermy

Question 6

Morula has how many cells?

Answer 6

32 or more varies really

Question 7

Which comes first blastula stage or morula?

Answer 7

blastula

Question 8

How does the blastocyst form?

Answer 8

forms as fluid develops in the morula

Question 9

What does the blastocyst consist of?

Answer 9

a cell mass known as the embryoblast and outer cell mass known as the trophobloast and blastocyst cavity

Question 10

What does the trophoblast become?

Answer 10

the placenta

Question 11

What does the trophoblast differentiate into by the end of week 1?

Answer 11

cytotrophoblast

Question 12

What is the most common form of ectopic pregnancy?

Answer 12

tubal

Question 13

What are the risk factors for an ectopic pregnancy?

Answer 13

endometriosis,
pelvic inflammatory disease,
tubular pelvic surgery,
exposure to DES (diethylstilbestrol)

Question 14

What are some signs of a tubal pregnancy?

Answer 14

abnormal or brisk uterine bleeding
sudden onset of abdominal pain that may be confused with appendicitis,
missed menstrual period (e.g LMP 60 days ago)
positive human chorionic gonadotropin test
culdocentesis showing intraperitoneal blood
positive sonogram

Question 15

Where does the abdominal form of ectopic pregnancy usually occur?

Answer 15

in rectourterine pouch (pouch of Douglas)

Question 16

For implantation to occur, what structure must degenerate?

Answer 16

zona pellucida

Question 17

Where does the blastocyst usually implant?

Answer 17

within the posterior wall of the uterus

Question 18

What layer of the uterus does the blastocyst implant in?

Answer 18

within the functional layer of the endometrium

Question 19

What stage of the menstrual cycle implantation take place in?

Answer 19

progestational phase

Question 20

At what week of development does the embryoblast differentiate into epiblast and hypoblast?

Answer 20

week 2

Question 21

What is the bilaminar embyronic disk composed of?

Answer 21

epiblast and hypoblast

Question 22

What is the prechordal plate?

Answer 22

the place where epiblast and hypoblast cells fuse and is site of future mouth

Question 23

What layer is extraembryonic mesoderm derived from?

Answer 23

epiblast

Question 24

Extraembryonic somatic mesoderm is found where?

Answer 24

lines the cytotrophoblast, forms connective stalk, and covers the amnion.

Question 25

Extraembryonic visceral mesoderm location?

Answer 25

covers the yolk sac

Question 26

What is the name for the lining of the chorionic cavity?

Answer 26

chorion

Question 27

What does the chorion consist of?

Answer 27

extraembryonic somatic mesoderm, the cytotrophopblast, and. synctiotrophoblast

Question 28

Does mitosis occur in synctiotrophoblast?

Answer 28

no

Question 29

Are cytotrophoblast mitotically active?

Answer 29

yes

Question 30

Where does hematopoiesis initially occur and at what stage?

Answer 30

occurs initially in the mesoderm surrounding the yolk sac (up to 6 weeks) and later in the fetal liver, spleen, thymus (6 weeks to third trimester) , and bone marrow

Question 31

What produces hCG?

Answer 31

human chorionic gonadotropin is a glycoprotein produced by synctiotrophoblast

Question 32

What is the purpose of hCG?

Answer 32

to stimulate progesterone production by corpus luteum

Question 33

What may low hCG predict?

Answer 33

a sponatenous abortion or ectopic pregnancy

Question 34

What may high hCG predict?

Answer 34

multiple pregnancy, hydatididorm mole, or gestational trophblastic disease

Question 35

What structures are formed within weeks 3-8 in major organ systems?

Answer 35

embryo starts to look human, and the nervous and cardiovascular systems start to develop

gastrulation takes place

Question 36

What is gastrulation?

Answer 36

process by which the 3 primary germ layers are produced:
ectoderm
mesoderm
endoderm

Question 37

What does ectoderm form during week 3?

Answer 37

neuroectoderm and neural crest cells

Question 38

What does mesoderm form during week 3?

Answer 38

paraxial mesoderm (35 pairs of somites),
intermediate mesoderm, and lateral mesoderm

Question 39

What is a sacrococcygeal teratoma?

Answer 39

a tumor that arises from remnants of the primitive streak; contains various types of tissue (bone, nerve, hair, etc.)

Question 40

Chordoma?

Answer 40

a tumor that arises from remnants of the notochord, found either intracranially or in the sacral region

Question 41

Hydatidiform mole?

Answer 41

results from the partial or complete replacement of the trophoblast by dilated villi

Question 42

Complete mole?

Answer 42

there is no embryo; a haploid sperm fertilizes a blighted ovum and reduplicates so that the karyotype is 46, XX, with all chromosomes of paternal origin

Question 43

Partial mole?

Answer 43

there is a haploid set of maternal chromosomes and usually 2 sets of paternal chromosomes so that the typical karyotype is 69, XXY

Question 44

Molar pregnancy hCG levels?

Answer 44

have high levels of hCG

Question 45

20% of molar pregnancies develop into what other conditions?

Answer 45

trophoblastic disease, including choriocarcinoma