1-F Early Development

Question 1

Explain the process of gametogenesis- the formation of female and male germ cells as described in these notes

Answer 1

a. Process that forms gametes (ovum and sperm) converting diploid cells into haploid cells by meiosis

Question 2

At birth all oogonium have become primary oocytes that are stuck in

Answer 2

prophase I

Question 3

What is the sequence of primordial follicule to ovulation?

Answer 3

primordial follicle, primary follicule, secondary follicle, ovulationof secondary oocyte with zona pellucida and corona radiata

Question 4

Primordial follicles consist of primary oocyte surrounded

Answer 4

zona pellucida and supported by follicular cells

Question 5

Maturation of primordial follicles mature through primary and secondary follicles and what forms in the follicular cell layer

Answer 5

antrum

Question 6

What is ovulated

Answer 6

a secondary oocyte including a zona pellucida and corona radiata

Question 7

After the ovum is released into the peritoneal most enter ____

Answer 7

the fimbriated end of the oviduct

Question 8

Ovulation causes the oocyte to re-enter what part of the cycle

Answer 8

meiosis and once again halting at metaphase II

Question 9

Locate where fertilization occurs

Answer 9

normally occurs at the ovarian end of the uterine tube, occurs once the sperm enters the secondary oocyte to form the zygote

Question 10

After fertilization all mitotic divisions are called:

Answer 10

cleavages

Question 11

Define early development

Answer 11

the process of zygote transforming into an embryonic disc (multicellular, tralaminar disc, period lasting 3 weeks

Question 12

Define differential growth

Answer 12

some areas grow more than others

Question 13

Define cavitaiton

Answer 13

hollowing out of a ball of cells

Question 14

Define cell migration

Answer 14

movement of cells from one place to another

Question 15

Define cell death

Answer 15

programed destruction of tissue due to development

Question 16

Define bud formation

Answer 16

bulging of cells open at one end

Question 17

Define tube formation

Answer 17

a cylinder of cells open at two ends

Question 18

Zygote

Answer 18

fusion of primary oocyte and sperm forming a diploid cell

Question 19

zona pellucida

Answer 19

glycoprotein layer which protects and nourishes the oocyte, found around the oocyte in the primordial follicule, primary and secondary follicle and zygote pre-implantation

Question 20

morula

Answer 20

16- cells stage of embryo made of a solid ball of blastomeres (undiferentiated and plueripotent)

Question 21

blastula

Answer 21

embryo after the morula cavitates, creating a hollow cavity called the bastocoel

Question 22

trophoblastic cells

Answer 22

of the blastula, the cells that form the outer surface of the cavity, they eventually become the placenta and extraembryonic membranes

Question 23

inner cell mass/ embryoblasts

Answer 23

one pole of the blastula has a concentration of cells that will develop into an embryo

Question 24

implantation

Answer 24

trophoblasts of the blastula attach to and burry into the uterine lining

Question 25

Why are ectopic pregnancies dangerous to the mother?

Answer 25

pregnancies that implant outside the uterus and are at great risk for vascular risk

Question 26

endometrium

Answer 26

uterine lining

Question 27

Embryo v. Fetus

Answer 27

embryo before 8 weeks, fetus after 8 weeks

Question 28

What happens during blastocyst "hatching"

Answer 28

blastocyst exits the zona pellucida as it degenerates and is ready for implantation

Question 29

Once blastula forms what is the first big step towards creating a bilaminar disc/

Answer 29

implantation occurs simulateously with diffentiation of trophoblasts and embryoblasts

Question 30

What are the two distinct layers of the inner cell mass that differentiate then cavitate

Answer 30

epiblast and hypoblast

Question 31

The cavities that are formed by the epiblas and the hypoblast will be joined an that region will develop into

Answer 31

the bilaminar disk

Question 32

Name the cavity formed once the epiblast cavitates

Answer 32

primitive amniotic cavity

Question 33

Name the cavity formed when the hypoblast cavitates

Answer 33

primitive yolk sac cavity

Question 34

During implantation, trophoblast cells differentiate into which two types of cells?

Answer 34

syncytiotrphoblasts and cytotrophblasts

Question 35

What is the role of cytotrophoblasts?

Answer 35

unfused cells surrounding the inner mass of cells, form a circle around the developing embryoblast

Question 36

What is the function of syntiotrophoblast cells?

Answer 36

fuse and burrow into to the endometrium, become supporting cells for the developing embryo, part of the developing placenta

Question 37

Which cells form the extraembryonic mesoderm?

Answer 37

cytrophoblasts

Question 38

Adding the extraembryonic mesoderm converts the primative extraembryonic tissues into:

Answer 38

amnion, chorion, extraembryonic coelom, connecting stalk

Question 39

amnion

Answer 39

primitive amnion plus extrembryonic mesoderm

Question 40

chorion

Answer 40

trophoblasts plus the extraembryonic mesoderm

Question 41

extraembryonic coelom

Answer 41

space separating the the chorion from the embryo, amnion and yolk sac, fetus grows into this space

Question 42

connecting stalk

Answer 42

attaches the chorion to the amniotic and yolk sac cavities and becomes the umbilical cord

Question 43

What is the function of the structures that will be produced by the extraembryonic mesoderm

Answer 43

future structures will support the developing embryo and fetus, forming no embryonic structures

Question 44

Describe major events associated with gastrulation

Answer 44

transformation of bilaminar disc to a trilaminar disc, formation of primative streak and migration of cells

Question 45

All 3 germ cell layers of formed from what type of embryoblast cells?

Answer 45

epiblast

Question 46

Name the three germ cell layers

Answer 46

ectoderm, mesoderm and endoderm

Question 47

Describe the migration that creaste mesoderm

Answer 47

cells that migrate through the primative streak and continue laterally

Question 48

Describe the migration of cells that create the endoderm

Answer 48

cells that migrate below the forming mesoderm to replace hypoblast cells

Question 49

How is the notochord formed?

Answer 49

migration of cells through the primative streak and directly cranially (mesoderm)

Question 50

Which spots on the trilaminar disc do not contain mesoderm

Answer 50

the oral and cloacal plates

Question 51

What directional details are established in gastrulation

Answer 51

body axes

Question 52

What do we call epiblast cells that do not migrate

Answer 52

ectoderm

Question 53

How is loose mesoderm formed

Answer 53

by epiblast cells that migrate through the primitive streak and migrate laterally

Question 54

What does the embryo look like at the end of gastrulation

Answer 54

trilaminar disc

Question 55

Name tissues formed by ectoderm

Answer 55

skin, nervous tissue

Question 56

Name tissues formed by the mesoderm.

Answer 56

muscle, bone, connective tissue, circulatory system

Question 57

Name tisses formed by the endoderm

Answer 57

epithelial linings of the gut tube, respiratory tract and the urinary tract

Question 58

What are the major features of development associated with the embryo

Answer 58

organstystems are formed, derived from the primitive germ layers