Patterning the brain

Question 1

Name the 6 majo subdivisions of the brain?

Answer 1

1. Forebrain
2. Midbrain
3. Cerebellum
4. Medulla
5. Pons
6. Spinal cord

Question 2

What does the forebrain do?

Answer 2

Consious thought

Memory

Learning

Question 3

What does the Midbrain do?

Answer 3

Regulates body temp

Motor control

Sleep cycles

Question 4

What does the Cerebellum do?

Answer 4

Co-ordinates complex motor patterns

Question 5

What does the Medulla do?

Answer 5

Regulates heart, lungs and digestive system

Question 6

What does the Pons do?

Answer 6

Sensory information relay to cerebellum

Question 7

What does the Spinal cord do?

Answer 7

Conveys signals to and from brain

Question 8

When is the CNS developed?

In what way is it developed?

Answer 8

From weeks 7 till weeks 40.

Develops from distinct anterior-posterior region.

Question 9

FGF/ Wnt signalling?

Answer 9

Neural induction

Leads to formation of the anterior neural plate.

Patterning of the midbrain/hindbrain boundary (important for the induction of the cerebellum)

Question 10

Homeobox genes?

Answer 10

Signals for segregation of the brain into: forebrain, midbrain and hindbrain.

Expressed in the notochord, prechordal plate and neural plate

Question 11

What does the homeobox genes code for?

Answer 11

Transcription factors that activate cascades for segmentation

Question 12

What are the segments called of the hindbrain?

Answer 12

8 of them

The rhombomeres

Question 13

Name the 4 Hox genes?

Answer 13

HoxA-D

Question 14

Hox genes?

Answer 14

Expressed in overlapping patterns in the hindbrain.

Genes are expressed earlier in the 3’ end and are more clustered.

Question 15

Retinoids?

Answer 15

Retinoic acid

A role in regulating Hox expression

Question 16

What happens if there is a deficiency in RA?

Answer 16

Small hindbrain

Question 17

What Hox genes are more sensitive to RA?

Answer 17

Hox genes are the 3’ end are more sensitive to RA

Question 18

Signalling pathway of the retinoids?

Answer 18

AS48

Question 19

What genese regulate the neural plate stages?

Answer 19

LIM1- expressed in the prechordal plate.

OXT2- expressed in the neural plate.

Question 20

What genes are expressed when the neural fold and pharyngeal arches appear?

Answer 20

OTX1

EMX1

EMX2

Question 21

Once the boundaries are established what two organising centers appear?

Answer 21

Anterior neural ridge

Isthmus

Question 22

Isthum?

Answer 22

Seperates the midbrain and hind brain

Question 23

In both anterior neural ridge and isthmus what is the key signalling molecule?

Answer 23

FGF8

Question 24

How is the FGF8 expressed in isthmus?

Answer 24

In a ring formation around the circumference

Question 25

FGF/ WNT patterns?

Answer 25

The mid-hindbrain

Question 26

Wnt1 expression ?

Answer 26

In a circumferential band anterior to the FGF8 expression.

Question 27

Interactions between the gene expressions?

Answer 27

AS49

Question 28

What controls the dorsal patterning of the neural tube?

Answer 28

Controlled BMP4-7

Question 29

What do the signals that inhibit BMP minic?

What does it promote?

Answer 29

The organiser

Promote formation of the anterior neural plate

Question 30

What does neural crest cells give rise to?

Answer 30

The peripheral nerve system