1E - Development (4)

Question 1

Neural plate, fold, groove

Answer 1

longitudinally oriented structures

Question 2

Where does thin surface ectoderm fuse?

Answer 2

Midline

Question 3

Lateral edges of neural tube have what shape cells?

Answer 3

Columnar

Question 4

Does the neural tube have a thicker columnar epithelium?

Answer 4

Yes

Question 5

On thin surface ectoderm, what shape cells are there?

Answer 5

Squamous-shape epithelium

Question 6

What is the point at which fusion occurs?

Answer 6

Neural crest

Question 7

Does the neural tube fold above notochord?

Answer 7

Yes

Question 8

Is surface ectoderm above neural crest?

Answer 8

Yes

Question 9

What does neural crest give rise too?

Answer 9

• PNS
• adrenal glands
• pigment cells of Iris

Question 10

Why do neural crest cells migrate away from neural crest?

Answer 10

Different migratory streams from neural crest form variety of tissues

Question 11

Where do columnar cells thicken?

Answer 11

Where nuclei are (located on outer surface of neural tube)

Question 12

What effect does outer surface neural tube nuclei have on shape?

Answer 12

• Apex of triangle points at lumen of neural tube
• Base (flat) part of triangle puts to external surface of tube
• This shape pattern allows neural tube to fold

Question 13

Voussior blocks form what?

Answer 13

arch

Question 14

Hinge regions act like what?

Answer 14

Voussoir blocks

Question 15

There are 3 hinge regions of what kind?

Answer 15

2 lateral

1 ventral

Question 16

How do hinge regions affect invagination of neural tube?

Answer 16

• hinge regions causes initial bending/folding of neural tube surface
• extensive growth of external thin surface epithelium
• once neural plate buckles at hinge regions, inward pressure cases neural plate to bend/invaginate further and to the 2 sides to approximate

Question 17

Surface ectoderm thickens to form what?

Answer 17

neural plate

Question 18

Notochord secretes Noggin and Chordin. Functions?

Answer 18

• Act on surface epithelium to thicken it
• Reach by diffusion
• Different regions of surface ectoderm get different doses of compounds

Question 19

Effect of compound is dose-dependent

Answer 19

• Region above notochord gets high dose of noggin and chordin
• Region farther away = lose dose

Question 20

Effect of compound is dose-dependent PART. 2

Answer 20

• Low dose lateral to neural plate = not enough to do anything
• Edges of neural plate = enough to thicken
• Edges of neural plate form protoneural crest

Question 21

protoneural crest

Answer 21

low dose of chordin, noggin

Question 22

High dose found in the medial of the neural plate which forms a specialized region in the neural tube

Answer 22

Floorplate

Question 23

signaling (organizing centers)

Answer 23

-region of embryo that secretes special chemicals that play a role in development

Question 24

Morphogens

Answer 24

• Affect growth of tissues around them
• Can appear and disappear
• Chemicals secretes from signaling centers are morphogens

Question 25

Edges of neural tube are darker

Answer 25

Due to Larger amount of tissue

Question 26

where is primitive streak located

Answer 26

caudal (posterior) to neural folds

Question 27

Where does notochord terminate? This structure is between border of forebrain and midbrain

Answer 27

Infundibulum

Question 28

Hensen's node is front of?

Answer 28

Primitive streak

Question 29

Notochord is under what?

Answer 29

Neural tube( is on top)

Question 30

Enlarged areas of neural tube become what?

Answer 30

brain

Question 31

back part of neural tube forms what?

Answer 31

spinal cord

Question 32

condensations of mesoderm that occur lateral of neural tube

Answer 32

somites

Question 33

Problems if neural tube fusion does not take place completely

Answer 33

1: Spina Bifida Occulta 2: Meningocele 3: MyeloMeningocele

Question 34

Spina Bifida Occulta

Answer 34

- Veterbrae incomplete - Incomplete fusion of spinal cord - not visible at surface - problem with closure of vertebral column

Question 35

Meningocele

Answer 35

-CNS surrounded by membranes called meninges -surface tissue not closed -herniation bubble occurs some meninges herniate out

Question 36

MyeloMeningocele

Answer 36

-primitive spinal cord tissue herniating out -spinal cord extending outside of body into Meningocele -can be surgically closed -long-term motor/sensory problems -skin is not closed across midline walls of sac made of meninges

Question 37

Myeloschisis

Answer 37

- surface tissue does not fuse - edges of neural fold don't use - most serious form of spina bifida - inside of neural tube is continuous with outside

Question 38

Encephalocele

Answer 38

- brain tissue herniating out - similar to MyeloMeningocele - rarae survival - retardation

Question 39

Encephalocele

Answer 39

- brain tissue herniating out - similar to MyeloMeningocele - rare survival - retardation