Nervous System

Question 1

Give the three primary and five secondary vesicles of the developing brain

Answer 1

Primary - Pro, Mes, and Rhomb (encephalon) comprising the forebrain, midbrain, and hindbrain. Secondary - Tel Di Mes Met Myel (encephalon)

Question 2

Give the three primary and five secondary vesicles of the developing brain

Answer 2

Primary - Pro, Mes, and Rhomb (encephalon) comprising the forebrain, midbrain, and hindbrain. Secondary - Tel Di Mes Met Myel (encephalon)

Question 3

Structures and cavities associated with the telencephalon in adults

Answer 3

Cerebral hemispheres, lateral ventricles

Question 4

Structures and cavities associated with the diencephalon in adults

Answer 4

Thalami, third ventricle

Question 5

Structures and cavities associated with the mesencephalon in adults

Answer 5

Midbrain, Aqueduct

Question 6

Structures and cavities associated with the metencephalon in adults

Answer 6

Pons and Cerebellum, Upper part of fourth ventricle

Question 7

Structures and cavities associated with the myelencephalon in adults

Answer 7

Medulla, lower part of fourth ventricle

Question 8

What are the three flexures of the brain?

Answer 8

Cervical, Midbrain, and Pontine

Question 9

The lumen of the spinal cord (central canal) is continuous with what brain structures?

Answer 9

The vesicles (lateral ventricles, third, fourth ventricles)

Question 10

What are the two ends of the neural tube called and when does each close?

Answer 10

Anterior neuropore (25 days), Posterior neuropore (27 days)

Question 11

Why is the early closing of the neural tube clinically significant?

Answer 11

The mother will not know she is pregnant, so she probably will not be taking folic acid, which greatly reduces risk of errors during neural tube closure

Question 12

What are the two types of neural support cells, and of what developmental origin is each?

Answer 12

Macroglia (from neuroepithelium) and Microglia (from mesenchyme)

Question 13

What is the original wall of the neural tube called, and what comes from here?

Answer 13

Neuroepithelial (ventricular zone) layer. Neurons and macroglia of the spinal cord come from here

Question 14

What two areas for the gray and white matter of the spinal cord respectively?

Answer 14

The mantle zone (forms gray matter) and marginal zone (forms white matter)

Question 15

What are the four thickenings of the developing spinal cord and what will each become?

Answer 15

Roof plate (Dorsal septum), Floor plate (Ventral median fissure), Alar plate (Dorsal horn), Basal plate (Ventral horn)

Question 16

What divides the developing dorsal and ventral horns of the spinal cord, and how is it produced?

Answer 16

The sulcus limitans. Produced by differential thickening, allowing it to delineate the alar plate (future dorsal horn) and basal plate (future ventral horn)

Question 17

Specify where neural crest cells come from, and name as many neural crest derivatives as you can

Answer 17

Edges of the neural folds. Derivatives - DRG, Sympathetic ganglia, Melanocytes, Chromaffin cells of adrenal gland, Ganglia of GI tract, Prevertebral ganglia

Question 18

What type of cells are macroglia derived from and what are those cells derived from?

Answer 18

Glioblasts, which are derived from Neuroepithelial cells

Question 19

What two cell types do macroglia give rise to and what does each of those types give rise to?

Answer 19

Astroblasts (Protoplasmic and Fibrous astrocytes), Oligodendroblasts (oligodendrocytes)

Question 20

From what cell type do microglia arise?

Answer 20

Monocytes (from mesenchyme) cells of blood vessels as the CNS becomes vascularized

Question 21

When do the primary brain vesicles (except the mesencephalon, which does not divide) divide to create the secondary brain vesicles?

Answer 21

During the 5th week

Question 22

What is another name for the aqueduct, what can happen to it, and what is the condition associated with this?

Answer 22

Duct of Sylvius, it can become obstructed, this causes hydrocephalus

Question 23

What does the pontine flexure do to the medulla and what is the effect on the developing plates?

Answer 23

It forces it to move laterally. This means the alar (sensory) plates will lie lateral to the basal (motor) plates

Question 24

What is the most common etiology of congenital malformations involving the spinal cord stem?

Answer 24

Defective closure of the neural tube

Question 25

Neural tube defects affect the developing tissue overlying the spinal cord. Give four examples of what types of tissue might be affected

Answer 25

Meninges, vertebral arches, muscles, skin

Question 26

What supplement helps prevent neural tube defects and what percentage does it prevent?

Answer 26

Folic acid, up to 70 percent

Question 27

Spina bifida is the term for neural tube defects that involve what structure?

Answer 27

The vertebral arches

Question 28

What is the difference between a meningocele and a meningomyelocele?

Answer 28

A meningocele occurs when the meninges expand abnormally posterior but the spinal cord develops normally. A meningomyocele occurs when the cord develops excessively posterior, through a hole. Both are types of spina bifida