EXAM 4: NORMAL STRUCTURE/FUNCTION OF THE NERVOUS SYSTEM

Question 1

What are the layers of the meninges?

Answer 1

Dura (outermost)
Arachnoid (middle)
Pia (innermost)

Question 2

What is the function of neurons?

Answer 2

Send, store, and receive electrical and chemical signals

Question 3

What are the 3 components of the glia?

Answer 3

Microglia
Astrocytes
Oligodendrocytes

Question 4

What is the function of microglia?

Answer 4

Local immune cells of the CNS

Question 5

What is the function of astrocytes?

Answer 5

Regulation, repair, and support

Question 6

What is the function of oligodendrocytes?

Answer 6

Myelin production (insulation)

Question 7

What makes up the gray matter?

Answer 7

Polio
Neurons
Stroma (neuropil)

Question 8

What makes up the white matter?

Answer 8

Leuko
axons

Question 9

Define: Encephalo

Answer 9

Brain

Question 10

Define: Myelo

Answer 10

Spinal Cord

Question 11

Define: Polio

Answer 11

Gray matter

Question 12

Define: Leuko

Answer 12

White matter

Question 13

Define: Itis

Answer 13

Inflammation

Question 14

Define: Osis

Answer 14

Degeneration

Question 15

Define: Malacia

Answer 15

Gross softening of the brain (necrosis)

Question 16

Define: Chromatolysis

Answer 16

Central
Degenerative change seen in cell body associated with axonal injury
Swelling of nerve cell body (perikaryon) with dispersion (loss) of Nissl substance and peripheral displacement of the nucleus

Question 17

Acute neuronal necrosis is a common response to what insult?

Answer 17

Excitatory toxicity

Question 18

What does acute neuronal necrosis look like histologically?

Answer 18

Shrunken and angular cell bodies with hypereosinophilic cytoplasm and pyknotic nuclei

Question 19

How do neurons look with lysosomal storage diseases?

Answer 19

Swelling of the neuronal cell body with finely vacuolated cytoplasm

Question 20

How do neurons look with prion diseases?

Answer 20

Transmissible spongiform encephalopathy characterized by large discrete cytoplasmic vacuoles

Question 21

What do aging changes in neurons look like?

Answer 21

Accumulation of orange-brown granular pigment “wear and tear” in aging neurons (lipofuscin)
No harmful effects

Question 22

Define: Wallerian Degeneration

Answer 22

Degeneration of the axon and its myelin sheath distal to the site of focal axonal injury (i.e. away from its cell body)

Question 23

Where does Wallerian degeneration occur in the spinal cord?

Answer 23

Ascending tracts - cranial to the site of focal axon injury
Descending tracts - caudal to the site of axon injury

Question 24

When do Alzheimer type II astrocytes occur?

Answer 24

With renal or hepatic encephalopathy

Question 25

What is the function of interfascicular (white matter) oligodendrocytes?

Answer 25

Formation and maintenance of myelin in CNS

Question 26

Define: Primary Demyelination

Answer 26

Degeneration/degradation of myelin sheath, with sparing of axon
Direct damage to myelin sheath or damage to myelin-producing cells (i.e. Schwann cells and oligodendrocytes)

Question 27

Define: Secondary Demyelination

Answer 27

Secondary to primary axonal injury (e.g. Wallerian degeneration)

Question 28

Define: Hypomyelinogenesis

Answer 28

Insufficient or absent myelin production

Question 29

Define: Dysmyelination

Answer 29

Formation of abnormal or unstable myelin

Question 30

Define: Microglial Cells

Answer 30

Resident mononuclear phagocytes (resident macrophages of the CNS)

Question 31

What are gitter cells?

Answer 31

Microglial cells
Phagocytosis of lipid/myelin debris

Question 32

Define: Neuronophagia

Answer 32

Phagocytosis of dead neurons by microglial cells

Question 33

How are small lesions repaired in the CNS?

Answer 33

Proliferation of astrocytes/processes

Question 34

How are larger lesions repaired in the CNS?

Answer 34

Cavitation or cystic spaces