Week 5 Objective 2

Question 1

Tripartite brain

Answer 1

prosencephalon
msencephalon
rhombencephalon

Question 2

Presencephalon is also known as

Answer 2

neuromere = prosomeres

prosencephalon gives way to the telenchephalon and diencephalon

Question 3

Mesencephalon

Answer 3

gives way to mesencephalon

Question 4

Rhombencephalon gives way to

Answer 4

rhombomeres

Metencephalon
Myelencephalon

Question 5

how many rhombomeres in the hindbrain of the human

Answer 5

7

Question 6

Tripartie brain established through what signaling molecule

Answer 6

Wnt-8 gradient

Question 7

Prosencephalon expresses what transcription factors?

Answer 7

Otx-2, future forebrain and (?) midbrain

Question 8

Mesencephalon expresses what transcription factors?

Answer 8

Otx-2

Question 9

rhombencephalon expresses

Answer 9

Gbx-1 transcription factor, future hindbrain and spinal chord

Question 10

Neural tube segmentation: 3 organizing centers

Answer 10

Isthmic organizer, anterior neural ridge, zona limitans

Question 11

Isthmic organizer

Answer 11

segmentation organizer

important in organizing midbrain and cerebellum
driven by wnt-1 and FGF-8

Question 12

Anterior neural ridge

Answer 12

organizes

telencephalon, diencephalon, pituitary gland, olfactory area

driven by Shh and FGF-8

Question 13

Zona limitans

Answer 13

organizers border between dorsal and ventral thalamus

drive by Shh

Question 14

Segmentation Genes in the hind brain

r3 and r5 are established via signaling molecule

Answer 14

knox 20

Question 15

r5 has half a dozen signaling molecules to organize its segment. what are they?

Answer 15

knox 20 and [kreisler and hoxa-1] , retinoic acid

Question 16

retinoic acid gradient establishes

Answer 16

r4-r-7

Question 17

Hox gene expression

Answer 17

patterning, segmentation

determines cranial nerves and pharyngeal arch derivatives

Question 18

retinoic acid gradient stimulates expression of

Answer 18

hoxa-1 and hoxb-2

Question 19

Why are caudalmost cells on the neural plate considered stem cells?

Answer 19

They’re undifferentiated and will go on to create neurons and the spinal column

Question 20

FGF-8

Answer 20

expressed by paraxial mesoderm: stimulates caudal neural plate cells to proliferate, but not differentiate

its retinoic acid that causes the differentiation

Question 21

FGF-8 causes

retinoic acid causes

Answer 21

FGF-8 causes proliferation (released by paraxial mesoderm)

retinoic acid causes differentation (released by somites)

Question 22

Why is neural crest tissue sometimes considered to be a fourth germ layer?

Answer 22

As neural tube is closing and separating from ectoderm, cells leave the tube and migrate to different places becoming many different structures

Question 23

What are sensory placodes?

Answer 23

ectodermal thickenings: cells from placodes and neural crest interact closely to form sensory ganglia of cranial nerves (V, VII, IX, and X)

Question 24

Where do the placodes come from?

Answer 24

from horseshoe shaped preplacodal domain around the anterior neural plate established during gastrulation