Fertilization and Gastrulation

Question 1

corona radiata

Answer 1

surround ovum, follicles from mom

Question 2

zona pellucida

Answer 2

glycoprotein layer of ovum

Question 3

perivitelline space

Answer 3

between PM and zona pellucida of ovum

Question 4

acrosome

Answer 4

part of head of sperm, contains enzymes

Question 5

middle piece of sperm

Answer 5

part of tail, have mitochondria

Question 6

fertilization occurs in the

Answer 6

ampula (distal 1/3 of fallopian/uterin tube)

Question 7

capacitation

Answer 7

glycoprotein coat and seminal plasma proteins removed from PM of head of sperm, need this to happen to release acrosome enzymes (acrosome reaction)

Question 8

sperm release ____ to penetrate corona radiata

Answer 8

hyaluronidase (and mucosal proteins)

Question 9

sperm release _____ to penetrate zona pellucida

Answer 9

esterases, acrosin, neuraminidase

Question 10

zona reaction

Answer 10

block to polyspermy, granules are released by egg into perivitelline space, react with zona, zona changes configuration into solid meshwork to block other sperm

Question 11

cleavage happens ___ hours after fertilization

Answer 11

30

Question 12

fertilization takes approximately ___ hours

Answer 12

24

Question 13

cleavage

Answer 13

inc in cell #, dec in cell size
embryo size unchanged
morula development (day 3)

Question 14

day 4

Answer 14

morula enters uterus

Question 15

zona pellucida starts to degenerate around day __

Answer 15

5

Question 16

late blastocyst

Answer 16

day 7, NO zona pellucida (embryo “hatches”)

Question 17

cells of trophoblast give rise to ______

Answer 17

the placenta

Question 18

early pregnancy factor

Answer 18

immunosuppressive, can use to detect

Question 19

cytotrophoblast

Answer 19

eventually replaces trophoblast
stem cell layer, mitotically active
give rise to syncytiotrophoblast

Question 20

syncytiotrophoblast

Answer 20

release proteolytic enzymes that start to erode into uterine lining
responsible for implantation and initial signal of pregnancy (release hCG)

Question 21

complete hydatidiform mole results from

Answer 21

1) fertilization of an EMPTY oocyte followed by duplication of the sperm or 2) fertilization of an EMPTY oocyte by 2 sperm

Question 22

what is a hydatidiform mole and what can it lead to

Answer 22

abnormal proliferation of trophoblast, excessive amounts of hCG produced
can lead to choriocarcinomas

Question 23

partial hydatidiform mole results from

Answer 23

fertilization of a NORMAL oocyte by 2 sperm

Question 24

inner cell mass

Answer 24

gives rise to epiblast (ectoderm, amnion, amniotic cavity)

intraembryonic

Question 25

hypoblast

Answer 25

extraembryonic endoderm, only exists during week 2 | prechordal plate, primary and secondary yolk sac, extraembryonic mesoderm

Question 26

extraembryonic somatic mesoderm

Answer 26

lining trophoblast and covering amnion

Question 27

extraembryonic splanchnic mesoderm

Answer 27

lining yolk sac

Question 28

connecting stalk

Answer 28

formed from EE somatic mesoderm, becomes umbilical cord

Question 29

primitive blood

Answer 29

formed from EE splanchnic mesoderm, forms in wall of yolk sac

Question 30

chorion

Answer 30

formed from EE somatic mesoderm, cytotrophoblast, syncytiotrophoblast layer of the placenta

Question 31

placenta previa

Answer 31

implant too close to the cervic internal os: near uterus external os: near cervix suggest C section

Question 32

give rise to all 3 germ layers

Answer 32

epiblast

Question 33

why do the prechordal plate and cloacal membrane die?

Answer 33

no component of mesoderm=no blood supply

Question 34

septum transversum

Answer 34

mesoderm, becomes part of diaphragm

Question 35

cardiogenic area

Answer 35

mesoderm, becomes heart, forms cephalad to prechordal plate

Question 36

chordomas

Answer 36

neoplasms of bone that arise from remnants of notochord, occur in axial skeleton in spheno-occipital region of skull and sacral regions

Question 37

paraxial mesoderm gives rise to...

Answer 37

somites (myotomes, sclerotomes, dermatomes)

Question 38

intermediate mesoderm gives rise to...

Answer 38

urogenital (kidney, gonads)

Question 39

lateral plate mesoderm gives rise to...

Answer 39

connective tissue (blood, lymph, mesenteries, CV)