Nervous System Development I Pt II

Question 1

Characteristics of the Isthmic Organizer

Answer 1

1. Located b/w Mesencephalon and the Metencephalon
2. It is a SIGNALING Center
3. Organizes and Polarizes Dorsal midbrain Midbrain and Cerebellum

Question 2

What is the Principal Signaling molecule of the Isthmic Organizer?

Answer 2

FGF-8

Question 3

What signaling molecules induce expression of En-1/2 and Pax-2/5?

Answer 3

1. FGF-8

2. Wnt-1

Question 4

Dorso-Ventral patterning of midbrain is primarily due to what?

Answer 4

SHH

Question 5

SHH restricts the expression of what in Dorso-Ventral patterning?

Answer 5

Pax-7

Question 6

What is the role of Pax-7?

Answer 6

Related to the formation of the ALAR plate

Question 7

What is the role of Pax-6?

Answer 7

1. Expressed in Alar plate
2. “Master Gene” of EYE formation
3. Inhibits En-1 and Vice-Versa
   - Results in the formation of the diencephalon and mesencephalon BORDER

Question 8

The forebrain is segmented into what?

Answer 8

3 Pro-Someres

9P1-3)

Question 9

Characteristics of P1-P3

Answer 9

Defines the Diencephalon

Question 10

Characteristics of P2-P3

Answer 10

Define the Dorsal/Ventral Thalamus

Question 11

The Alar plate develops into what?

Answer 11

• Cerebral Cortex
• Basal Nuclei
• Optic Vesicles

Question 12

Motor Axon Outgrowth

Answer 12

• Axons grow out from the motor neuroblast

located in the basal plate of the spina cord

Question 13

What maintains the separation b/w CNS and PNS

Answer 13

Boundary CAPS

• Created by Neural Crest Cells

Question 14

Formation of a sensory neuron

Answer 14

• Cell bodies of sensory neurons are derived from Neural Crest Cells
  (They form sensory spinal ganglia)
• Boundary caps maintain the separation

Question 15

Cells bodies of sensory neurons form what?

Answer 15

Sensory Spinal Ganglia

Question 16

Cues involved in Axon guidance

Answer 16

1. Caudal Half of somite
2. Fibronectin
3. Laminin
4. Integrins
5. Cadherins

FLICC

Question 17

Role and Relationship of Pioneering Axon

Answer 17

The first axons to grow in a particular region

• Main fxn is laying down the initial growing path that subsequent growing axons
• NO anatomical difference b/w Pioneer and Follower axons

Question 18

What happens when a Motor Axon meets a muscle fiber?

Formation of NMJ

Answer 18

1. Cessation of Outgrowth of Axon
2. Preparation by Neuron for release of NT molecules (ACh)
3. Muscle fiber preparation for signal transduction

Question 19

What determines whether migrating neural crest cells differentiate into Autonomic neurons or other neural crest derivatives?

Answer 19

BMPs

Question 20

The sympathetic Pre-Ganglionic MN arise from what?

Answer 20

Intermediate Lateral Horns of Gray matter

Question 21

T/F: Sympathetic POST-Ganglionic MN are myelinated.

Answer 21

False

• They are NOT Myelinated

Question 22

The Parasympathetic Pre-Ganglionic MN are associated with what kinds of nerves?

Answer 22

Cranial Nerves

• 3, 7, 9, and 10

Question 23

Sympathetic cells are typically _____ and Parasympathetic cells are typically _____.

Answer 23

1. Adrenergic

2. Cholinergic