Lab Exam 2: Embryology

Question 1

zygote

Answer 1

fertilized egg

Question 2

fertilization

Answer 2

egg and sperm nuclei fuse to form single nucleus

Question 3

blastomeres

Answer 3

zygote begins to divide

forms mass of successively smaller and smaller cells

Question 4

cleavage

Answer 4

series of mitotic divisions without intervening growth periods
results in multicellular embryonic body

Question 5

morula

Answer 5

solid ball of cells
at the 32-cell stage
embryo resembles a berry shape

Question 6

blastula

Answer 6

the cell mass hollows out
ball of cells surrounding a central cavity
this is the final product of cleavage

Question 7

early gastrula form

Answer 7

one end of blastula has been indented or pushed into the central cavity forming a 2 layered embryo

Question 8

gastrulation

Answer 8

3 layered embryo forms

each layer corresponds to a primary germ layer that all body tissues develop from

Question 9

endoderm

Answer 9

innermost layer of primary germ layer

- epithelial lining of respiratory, GI, reproductive tracts, liver, gallbladder

Question 10

mesoderm

Answer 10

middle layer of primary germ layer

- dermis, skeleton, cardiac, smooth muscle, blood vessels, serous membranes

Question 11

ectoderm

Answer 11

outer layer of primary germ layer
forms surface tissues of the body
- skin, nervous system, senses, nasal and anal cavities

Question 12

blastocyst

Answer 12

fluid filled sphere outlined by trophoblast

final product of cleavage

Question 13

trophoblast

Answer 13

single layer of flattened cells enclosing the embryoblast

Question 14

embryoblast

Answer 14

inner cell mass

Question 15

chorion

Answer 15

this is what a trophoblast forms , it is an extraembryonic membrane
forms the fetal portion of the placenta

Question 16

embryonic disc

Answer 16

forms the embryo proper

has 2 layers

Question 17

How long is implantation?

Answer 17

about 5 days, it is completed by 12 days after fertilization

Question 18

portion of embryoblast that eventually lies beneath the embryo

Answer 18

decidua basalis

Question 19

portion of endometrium on the luminal face of the uterus

Answer 19

decidua capsularis

Question 20

by the time implantation has completed, embryonic development has progressed to what stage?

Answer 20

gastrula stage

Question 21

when is the embryo considered a fetus?

Answer 21

by week 9 of development

Question 22

composite of decidua basalis and chorionic villi

Answer 22

placenta

Question 23

three extraembryonic membranes

Answer 23

amnion, yolk sac, and allantois

Question 24

encases the young embryonic body in a fluid-filled chamber that protects embryo against mechanical trauma and temperature extremes , prevents adhesions during rapid embryonic growth

Answer 24

amnion

Question 25

in humans: yolk sac lost original function which was to | pass nutrients to embryo after digesting the yolk mass , now the role of?

Answer 25

placenta

Question 26

where embryos first blood cells originate and primordial germ cells migrate from it into embryo's body to seed gonadal tissue - forms part of digestive tube

Answer 26

yolk sac

Question 27

protrudes from posterior end of yolk sac - redundant in humans bc of placenta - birds and reptiles: embryonic wastes - humans: structural basis on which the mesoderm migrates to form umbilical cord

Answer 27

allantois

Question 28

attaches embryo to placenta

Answer 28

umbilical cord

Question 29

4 cell stage

Answer 29

2 days

Question 30

oocyte

Answer 30

egg

Question 31

early blastocyst

Answer 31

morula hollows out and fills with fluid, 4 days

Question 32

zona pellucida

Answer 32

area around the blastocyst

Question 33

ceolom

Answer 33

hollow, fluid-filled cavity that will provide cushion for internal organs

Question 34

uterus

Answer 34

organ where offspring are conceived

Question 35

uterine cavity

Answer 35

inside of uterus, triangular shape

Question 36

fertilization membrane

Answer 36

membranous layer that forms post fertilization by thickening membrane, on microscope it looks like halo around cell

Question 37

amniotic cavity vs amnion

Answer 37

amniotic cavity : closed sac between amnion and embryo containing amniotic fluid amnion: is the membrane forming the fluid-filled cavity

Question 38

endometrium

Answer 38

mucous membrane lining the uterus, thickens during menstrual cycle

Question 39

blastocyst cavity

Answer 39

cavity in the morula that is filled with fluid

Question 40

ovulation

Answer 40

process when mature egg is released from an ovary - it is halfway through a menstrual cycle, about 6 days - best time to get pregnant

Question 41

fallopian tube

Answer 41

where conception occurs

Question 42

ovary

Answer 42

female glands where estrogen and progesterone are made | eggs are also made in the ovaries