Embryology

Question 1

conception to week 2

Answer 1

pre-embryonic period

Question 2

week 3-8

Answer 2

embryotic period

Question 3

week 9-38

Answer 3

fetal period

Question 4

pre-embryonic period

Answer 4

formation of morula; morula -> blastocyst; implantation

Question 5

embryotic period

Answer 5

gastrulation; neurulation; embryotic folder; major body systems form; most susceptible to teratogens during this time

Question 6

fetal period

Answer 6

structural and functional growth of major body systems

Question 7

fertilization

Answer 7

fertilization -> zygote travels down the uterine tube

Question 8

zygote

Answer 8

undergoes rapid mitotic cell divistion without increasing in size

Question 9

cleavage

Answer 9

cell division continues until blastomeres

Question 10

blastomeres

Answer 10

16 daughter cells within the zona pellucida

Question 11

zona pellucida

Answer 11

contains blastomeres; generated when blastocyst forms - growth and implant into iterus

Question 12

morula

Answer 12

compact sphere fo cell (4 days)

Question 13

blastocyst

Answer 13

embryoblast (cell cluster) - blastocyst cavity - trophoblast

Question 14

trophoblast

Answer 14

penetrate the endometrium lining of uterinr -> implantation begin at the end of week 1

Question 15

hypoblast

Answer 15

proliferate and migrate to form the lining of the primary yolk sac - source of nutrition for the embryo before the placenta is functional

Question 16

epiblast

Answer 16

amniotic cavisity - some spiblast cells become specialize to secrete amniotic fluid

Question 17

syncytiotrophoblast

Answer 17

invade maternal capillaries and establish the uteroplacental circulation; produce hCG (human chorionic gonadotrophin) detected by pregnancy tests/

Question 18

cytotrophoblast

Answer 18

inner layer of trophoblast (actively divising). Loose cell walls and form syncytiotrophoblast

Question 19

chorionic cavity

Answer 19

lined by extraembryomic mesoderm (loose CT from primary yolk sac)

Question 20

amniotic cavity

Answer 20

above epiblast

Question 21

primary yolk sac degenerate

Answer 21

a smaller secondary or definitive yolk sac is created -> gut tube

Question 22

connecting stalk

Answer 22

extension of extraembryonic mesoderm connectsthe embryo to the cytotrphoblast -> eventually forms the umbilical cord

Question 23

Gastrulation

Answer 23

trilaminar enbryonic (germ) disc

Question 24

primitive streak

Answer 24

appears during gastrulation and is used to determin the three main body axes.

Question 25

ectoderm

Answer 25

outer skin - covering of the body (spidermis) and nervous system

Question 26

mesoderm

Answer 26

skeletal connective, muscule tissues

Question 27

endoderm

Answer 27

inner lining of the GI and respiratory systems

Question 28

Surface ectoderm

Answer 28

epidermis of the skin, glands, hair, nails, tooth enamel, lens and cornea of the eye, and induces the development of the limb buds.

Question 29

Neuroectoderm

Answer 29

neuro tube + neuro crest

Question 30

neuro tube

Answer 30

gives rise to the central nervous system (brain and spinal cord)

Question 31

neuro crest

Answer 31

migrate and form many structures in the developing embryo including portions of the heart, bones of the face, and ganglia (nerve cell bodies) of the peripheral nervous system. Neural crest cells are particularly vulnerable to teratogenic insult.