Fertilization and Gastrulation

Question 1

follicular cells that cover the egg

Answer 1

Corona Radiata

Question 2

Glycoprotein meshwork important for zone reaction

Answer 2

Zona Pellucida

Question 3

Part of the sperm which contains the mitochondria

Answer 3

Middle piece of tail, has mitochondrial sheath

Question 4

Where does fertilization occur?

Answer 4

ampulla of the fallopian tube

Question 5

Fertilization, cleavage, formation of blastocyst, formation of inner cell mass (embryoblast), and implantation

Answer 5

Week 1 events (0-7)

Question 6

occurs in uterus and uterine tubes; glycoprotein coat on the head of sperm is removed allowing for acrosome reaction and passage of sperm through corona radiata

Answer 6

Capacitation (7 hours)

Question 7

What enzyme is initially released by the sperm to penetrate the corona radiata?

Answer 7

hyalouronidase

Question 8

Penetration of zona pellucida

Answer 8

esterases, acrosin, and neuraminidase released to penetrate; perivitelline space releases granules to help the zone reaction

Question 9

Zona reaction

Answer 9

when one sperm breaks through zona pellucida a conformation change occurs to make it more rigid and prevent polyspermy

Question 10

Perivitelline Space

Answer 10

Where egg cells release granules to help zona reaction

Question 11

Morula

Answer 11

after 8 cell stage; day 3; 12-32 cells

Question 12

Morula enters body of uterus and fluid diffuses in, forming a cavity

Answer 12

formation of the blastocyst; day 5

Question 13

gives rise to placenta

Answer 13

trophoblast

Question 14

gives rise to embryo

Answer 14

inner cell mass

Question 15

Releases early pregnancy factor to protect embryo during first 10 days

Answer 15

trophoblast

Question 16

stem cell layer that is mitotically active

Answer 16

Cytotrophoblast

Question 17

multinucleate without a plasma membrane; release proteolytic enzymes for implantation chorionic gondatotropin (hCG)

Answer 17

Syncytiotrophoblast

Question 18

Formation of a bilaminar disc and implantation

Answer 18

Week 2 events

Question 19

Epiblast (ectoderm, amnion, amniotic cavity) and the hypoblast (only during week 2) derived from:

Answer 19

Inner Cell Mass

Question 20

Extraembryonic endoderm which gives rise to prechordal plate (fuses to epiblast forming future mouth), primary and secondary yolk sac (umbilical vesicles), and extraembryonic mesoderm

Answer 20

Hypoblast

Question 21

Hollow cavity outside of embryo

Answer 21

Extraembryonic coelom

Question 22

Lines the trophoblast and covers the amnion

Answer 22

Extraembryonic Somatic Mesoderm

Question 23

Lines the yolk sac (umbilical vesicle)

Answer 23

Extraembryonic Splanchnic Mesoderm

Question 24

from extraembryonic somatic mesoderm; forms at embryonic pole; position changes during development

Answer 24

Connecting Stalk (umbilical cord)

Question 25

Extraembryonic splanchnic mesoderm derivative; forms in the walls of the yolk sac

Answer 25

Primitive Blood

Question 26

Extraembryonic somatic mesoderm derivative; also includes cytotrophoblast and syncytiotrophoblast; part of placenta

Answer 26

Chorion

Question 27

Usually happens in posterior wall of uterus after 6 days

Answer 27

implantation

Question 28

zygote implants in the wrong area of the uterus; often in the uterine tube and can lead to severe problems

Answer 28

Abnormal Implantation or Ectopic Pregnancy

Question 29

vaginal bleeding beyond 20 weeks gestation; placenta implants over the internal cervical os; marginal, partial, and total

Answer 29

Placenta Previa

Question 30

formation of the three germ layers that give rise to all tissues; comes from the epiblast

Answer 30

Gastrulation

Question 31

Formed from ectoderm

Answer 31

skin, hair, nails, CNS, brain

Question 32

Formed from mesoderm

Answer 32

connective tissues, bone, muscle, blood, heart, spleen

Question 33

Formed from endoderm

Answer 33

lungs, GI organs, bladder, glands

Question 34

Forms in caudal portion of embryo; primitive node/knot at top with the streak coming down

Answer 34

Primitive Streak

Question 35

Cells at primitive streak meet and are pushed down to form true embryonic endoderm (replacing hypoblast) and mesoderm

Answer 35

Formation of the layers

Question 36

future diaphragm (rostral)

Answer 36

septum transversum (mesoderm)

Question 37

future heart (rostral)

Answer 37

cardiogenic area (mesoderm)

Question 38

Prechordal plate only made up of two layers (no blood supply); future mouth

Answer 38

endoderm and ectoderms

Question 39

Cloacal membrane only two layers and no blood supply; common membrane for urinary, digestive, and reproductive systems

Answer 39

endoderm and ectoderm

Question 40

mesoderm from primitive pit towards prechordal plate; template for vertebral column, longitudinal axis for embryo, and induces the formation of neural plate and CNS

Answer 40

Notochord

Question 41

posterior midline diverticulum from wall of yolk sac; endoderm; template for umbilical arteries and veins; BECOMES URACHUS

Answer 41

Allantois