Lecture 17 (Exam 2)

Question 1

Spinal cord ______ ______ is centrally located in the form of anterior, posterior, and lateral horns situated around the central canal.

Answer 1

Gray matter

Question 2

In the brain, deep areas of (WHITE/GRAY) matter are represented by the basal nuclei and other nuclear groups. (WHITE/GRAY) matter is in the form of myelinated fiber tracts throughout various parts of the brain that, in general, lie superficial to the deep (WHITE/GRAY) matter.

Answer 2

Gray
White
Gray

Question 3

In the cerebrum and cerebellum, additional external areas of gray matter, the _______, are built on top of (external to) the myelinated white matter tracts.

Answer 3

Cortices

Question 4

A true _______ consists of multiple layers of gray matter (typically, 6 in the ______ ______).

Answer 4

Cortex

Cerebral cortex

Question 5

T/F. A true cortex is built from the outside in, with the deepest layers being added last.

Answer 5

False. A true cortex is built from the inside out, with the most superficial layers being added last.

Question 6

An exception that can occur is when the neuronal migration in the building of the cerebellar cortex occurs (PARALLEL/PERPENDICULAR) to the surface (rather than (PARALLEL/PERPENDICULAR)) in the early stages.

Answer 6

Parallel

Perpendicular

Question 7

An exception that can occur is when the cerebellar cortex and some areas of the cerebral cortex consist of ______ layers instead of 6.

Answer 7

3

Question 8

An exception that can occur is when some parts of the cerebral cortex are built from (INSIDE/OUTSIDE) to (INSIDE/OUTSIDE).

Answer 8

Outside

Inside

Question 9

There are a special type of glial cell (thought by many to be a subdivision of astrocytes). They are located in the ventricular (ependymal) zone.

Answer 9

Radial glial cells

Question 10

Each of these cells extend a long process that passes through the intermediate zone, cortical plate, and marginal zone to the surface of the brain.

Answer 10

Radial glial cells

Question 11

Migrating ______ ______ use the long process of radial glial cells as a guiding mechanism to reach the surface where they can begin to layer the cortex.

Answer 11

Bipolar neurons

Question 12

The topographical arrangement of the myelencephalon is almost identical to the spinal cord. What is the major topographical change?

Answer 12

Pronounced expansion of the roof plate to form the thin roof over the fourth ventricle

Question 13

Expression of which set of genes seems to be responsible for the differentiation of specific nuclei in the myelencephalon?

Answer 13

Hox genes

Question 14

What are the major derivatives of the metencephalon?

Answer 14

Pons (basal plate)

Cerebellum (alar plate)

Question 15

The cerebellum forms in the region of the rhombic lips (rhombomeres 1-8). The rhombic lips are the product of what inductive interaction?

Answer 15

Roof plate and neural tube via BMP signaling

Question 16

What is the migration of the cells that will form the cortex in the cerebellar primordium?

Answer 16

1) Granule cells migrate anteriorly along dorsal region of rhombomere 1.
2) Granule cells migrate interiorly through Purkinje layer.
3) Purkinje cells migrate radially through granule cells.

Question 17

What are the superior cerebellar peduncles?

Answer 17

Massive fiber bundles between the cerebellum and the mesencephalon.

Question 18

What are the major derivatives of the alar plates of the mesencephalon?

Answer 18

Superior colliculi
Inferior colliculi

***Collectively called the tectum (corpora quadrigemina)

Question 19

Where is Otx-2 located and how is it related to Shh?

Answer 19

Located in region of border between alar and basal plates.

It confines Shh to the basal part of the midbrain.

Question 20

Where do the cerebral peduncles form and what is their function?

Answer 20

Ventrolateral region of the mesencephalon.

They carry fibers between the cerebral hemispheres and the spinal cord.

Question 21

What are the major derivatives of the diencephalon?

Answer 21

Epithalamus
Thalamus
Hypothalamus

Question 22

What are the three patterning centers in the forebrain?

Answer 22

Rostral patterning center
Dorsal patterning center
Ventral patterning center

Question 23

What does the rostral patterning center secrete?

Answer 23

FGF-8

Question 24

What does the dorsal patterning center produce?

Answer 24

BMPs

Wnts

Question 25

What does the ventral patterning center produce?

Answer 25

Shh