Lecture 1

Question 1

sperm and egg create

Answer 1

a zygote

Question 2

a zygote divides and forms a dense ball called a

Answer 2

murula

Question 3

t/f the murula becomes a hollow ball

Answer 3

true

Question 4

define cleavage

Answer 4

the embryo divides rapidly without increasing its overall size

Question 5

t/f during cleavage the size of the ball of the cells increases

Answer 5

false it stays the same

Question 6

after 4-5 where does the embryo go

Answer 6

in the uterus

Question 7

what is a blastocyst

Answer 7

after 4-5 days embryo is in the uterus and has started accumulating fluid inside of it .

Question 8

when does fertilization occur

Answer 8

when a sperm fuses with an egg to form a zygote

Question 9

what are 3 ways that sperm are destroyed

Answer 9

acidic environment , leakage , destruction by defense cells

Question 10

does mitotic division after fertilization result in larger or smaller cells

Answer 10

smaller

Question 11

what are the 2 kinds of cleavage

Answer 11

holoblastic or meroblastic

Question 12

is meroblastic total or partial cleavage

Answer 12

partial

Question 13

t/f the amount of yolk determines if something is meroblastic or holoblastic

Answer 13

true

Question 14

t/f humans are meroblastic

Answer 14

false

Question 15

does cleavage occur before or after fertilization

Answer 15

after

Question 16

does cleavage result in bigger or smaller cells

Answer 16

smaller

Question 17

where does implantation occur

Answer 17

in the endometrium of the uterus

Question 18

what is the mitotic division after fertilization called

Answer 18

cleavage

Question 19

t/f cleavage happens on the yolk free side

Answer 19

true

Question 20

what is a fertilized egg calle d

Answer 20

zygote

Question 21

after cleavage at least 4 initial cell divisions occur resulting in a dense call of at least 16 cells called a

Answer 21

morula

Question 22

a fluid filled hollow spear is also known as a

Answer 22

blasocyst

Question 23

what are the names of the 2 different poles in an egg

Answer 23

animal pole

vegital pole

Question 24

what is teh 1st envelope -in contact with the membrane of the egg made of

Answer 24

glycoproteins

Question 25

what is gastrulation

Answer 25

the processing of forming 3 germ layers

Question 26

what are the 3 germ layers

Answer 26

ectoderm , endoderm , mesoderm

Question 27

neural tissue is what kind of germ layer

Answer 27

ectoderm

Question 28

during gastrulation where do cells that were originally part of embryo move

Answer 28

inwards to become the mesoderm

Question 29

when does gastrulation begin

Answer 29

with the appearance of a primitive streak

Question 30

during what week does the primitive streak occur

Answer 30

3rd week

Question 31

what is the primitive streak made out of

Answer 31

epiblast cells form a thickening called the primitive streak , it is at its crainial end

Question 32

what does the absence of a hypoblast result in

Answer 32

multiple primitive streaks

Question 33

prior to gastrulation what will tissue turn into

Answer 33

epidermal derivitives like the skin

Question 34

after gastrulation what will tissue turn into

Answer 34

it will turn into neural tissue

Question 35

which end is the animal pole : yolk or yolk free

Answer 35

yolk free

Question 36

is the vegetal pole yolk or yolk free

Answer 36

yolk

Question 37

The entire ???? comes from the ?????

Answer 37

nervous system , ectoderm

Question 38

what is the primary importance of gastrulaiton ?

Answer 38

it changes the fate of a cell from epidermis to neural tissue

Question 39

does development of the nervous system begin at the early or late stages of embryogenesis

Answer 39

late

Question 40

do the 3 germ layers generate before or after development of the nervous system ?

Answer 40

before

Question 41

what is the innermost germ layer called

Answer 41

endoderm

Question 42

what is the middler germ layer called

Answer 42

mesoderm

Question 43

what is the outermost germ layer called

Answer 43

ectoderm

Question 44

name the germ layer : gives rise to connective tissue , muscle , vascular system

Answer 44

mesoderm

Question 45

name the germ layer : gives rise to the major tissues of the central and peripheral nervous system

Answer 45

ectoderm

Question 46

name the germ layer : gives rise to gut lungs and liver

Answer 46

endoderm

Question 47

the entire nervous system rises from

Answer 47

the ectoderm

Question 48

the part of the ectoderm that is directly over the __ becomes neural tissue

Answer 48

mesoderm

Question 49

the part of the embryo that will become neural tissue is initially a flat___ ____

Answer 49

neural plate

Question 50

after the neural plate folds , what is it called

Answer 50

a neural tube

Question 51

cells at the edge of the neural plate become the ___

Answer 51

neural crest

Question 52

what does neurulation refer to

Answer 52

the formation of the neural plate and neural tube is called neurulation

Question 53

what does the caudal region of the neural tube give rise to

Answer 53

the spinal cord

Question 54

what does the rostral region of the neural tube give rise to

Answer 54

brain

Question 55

is the extent of cell proliferation uniform along the length of the neural tube

Answer 55

no

Question 56

define neural induction

Answer 56

the development of neural tissue

Question 57

what are the 2 main factors of neural induction ?

Answer 57

1- inducing factors: signaling molecules provided by other cells 2-molecules that are activated upon exposure to inducing factors

Question 58

t/f the position that a cell occupies early in the development is not very important in determing fate

Answer 58

false

Question 59

what are the 3 things that a cells fate is determined by

Answer 59

signals to which it is exposed where it finds itself in the embryo profile of genes it expresses as a consequence of its developmental history

Question 60

the neural plate is induced by signals from the adjacent...

Answer 60

mesoderm

Question 61

what region is also known as the speeman organizer

Answer 61

the dorsal lip

Question 62

what is the 1st molecule identified as a neural inducer called

Answer 62

noggin

Question 63

what is a gene that the organizer expressed

Answer 63

chordin

Question 64

t/f injection of chordin can induce another body axis and rescue ventralized embryos

Answer 64

true

Question 65

what was the last molecule discovered to play a role in mesoderm induction

Answer 65

follistatin

Question 66

what does follistatin bind to and inhibit

Answer 66

activin

Question 67

if acitivan is injected into embryos what occurs

Answer 67

neural tissue is created

Question 68

what are the 3 molecules secreted from the organizer to promote neural induction

Answer 68

noggin , chordin , follostatin

Question 69

when follistatin can no longer bind to activan what is created

Answer 69

neural tissue