Neuro I

Question 1

duplication at 2 cell blastocyst stage

Answer 1

2 separate sets of fetal membranes

Question 2

duplication of inner cell mass

Answer 2

free twins of two separate embryonic discs; asymmetrical if unequal separation;
shared fetal yolk sac and chorion

Question 3

gastrula: complete duplication of primitive streak

Answer 3

conjoined (tissues/organs)
symmetrical (2 complete, separate axes)
2 heads and vertebral columns

Question 4

gastrula: incomplete duplication of primitive streak

Answer 4

conjoined, symmetrical; duplicated region 2 axes
unduplicated region; 1 axis;
at gastrula, all fetal membranes shared

Question 5

duplication of gastrula without duplication of primitive streak

Answer 5

conjoined, asymmetrical
1 axes
other body tissues/ parts duplicated
especially limbs

Question 6

what is the notochord

Answer 6

mesodermal rod;

Question 7

notochord begins at

Answer 7

primitive node - deep to it and ectoderm

Question 8

notochord oriented

Answer 8

craniocaudal along midline of longitudinal axis of embryo

Question 9

notochord expands

Answer 9

cranial and caudal

Question 10

as the notochord expands caudally, primitive streak ____

Answer 10

disappears

Question 11

paraxial mesoderm

Answer 11

next to axis; mesodermal columns or bands, located on either side of notochord

Question 12

what forms the paraxial mesoderm

Answer 12

somites from left and right pairs

Question 13

somites form _____

Answer 13

sequentially from cranial to caudal

Question 14

which forms first

Answer 14

cranial most pair

Question 15

somites give rise to

Answer 15

segmental skeletal/connective tissue structures and muscle units (pattern imposed on developing peripheral nervous system)

Question 16

first several fuse and contribute to

Answer 16

head structures

Question 17

canine somites caudal to head include

Answer 17

8 cervical
13 thoracic
7 lumbar
3 sacral
10-20 caudal

Question 18

notochord and paraxial mesoderm together begin

Answer 18

NS development

Question 19

overlying ectoderm induce

Answer 19

neurectoderm (ectoderm above the notochord)

Question 20

rest of ectoderm (surface ectoderm)

Answer 20

becomes epidermis

Question 21

neuroectoderm gives rise to

Answer 21

neural plate

Question 22

neuronal progenitors

Answer 22

neurons

Question 23

glial progenitors

Answer 23

astrocytes, oligodendrocytes, etc (excludes microglia)

Question 24

ependymal cells

Answer 24

line tubes and ventricles

Question 25

formation of primary neural tube is the formation of

Answer 25

brain and majority of psinal cord and associated nerves

Question 26

primary neural tube develops from

Answer 26

neural plate

Question 27

neural plate is

Answer 27

proliferation and thickening of neuroectoderm

Question 28

majority of the neural plate is

Answer 28

CNS

Question 29

neural crest cells at edge of neural plate

Answer 29

PNS

Question 30

Neural folds do what

Answer 30

elevate and grow toward each other at lateral edges

Question 31

center of neural plate does what

Answer 31

sinks along long axis of body to from neural groove

Question 32

neural crest cells are found at the junction of

Answer 32

neuroectoderm and surface ectoderm

Question 33

as neural folds continue to grow toward one another, what happens to the neural groove

Answer 33

deepens

Question 34

neural folds fuse to become

Answer 34

neural tube

Question 35

neural tube created is a complete circle of

Answer 35

complete circle of neuroepithelium surrounding a neural canal

Question 36

neural cres cells isolate from

Answer 36

neuroepithelium of neural tube and surface ectoderm, located between them on either side of the axis

Question 37

surface ectoderm meets and fuses above

Answer 37

neural structures

Question 38

fusion begins in the center and extends

Answer 38

outward along body axis in both directions (cranially and caudally)

Question 39

chicks develop from

Answer 39

a single intitial fusion point while mammals tend to have multiple initial fusion points

Question 40

openings at rostral and caudal ends are

Answer 40

rostral neuropore and caudal neuropore

Question 41

primary neurulation is complete when

Answer 41

rostral and caudal neuropores are closed

Question 42

secondary neurulation begins after

Answer 42

closure of caudal neuropore and completion of primary neurulation

Question 43

located at about the _____ pair of somites

Answer 43

35th

Question 44

secondary neural tube arises from

Answer 44

neuroectodermal cells of the tail bud or caudal eminence

Question 45

proliferation and condensation of cells

Answer 45

x

Question 46

caviation

Answer 46

forming a central cavity or lumen

Question 47

fuses with caudal end of

Answer 47

primary neural tube

Question 48

lumen becomes conitnuous with

Answer 48

neural canal

Question 49

neural canal

Answer 49

ventricular system