Module 12 - Diseases of the CNS

Question 1

abscess

Answer 1

a localized area of infection filled with pus, and associated with tissue destruction and/or swelling.

Question 2

amyloid

Answer 2

an extracellular protein substance; it is a waxy, amorphous, and eosinophilic material that may be stained with Congo red. Amyloid deposits are composed of straight, non-branching fibrils.

Question 3

apolipoprotein E

Answer 3

a protein involved in lipid transport in blood and brain. Three isoforms exist, apoE3 (most common), apoE4 (associated with an increased risk of Alzheimer’s disease (AD)) and apoE2 (may confer protection against development of AD).

Question 4

astrocyte

Answer 4

a class of glial cells; star-shaped cell which provides mechanical support and helps maintain the ionic composition within the central nervous system.

Question 5

central nervous system (CNS)

Answer 5

the central parts of the nervous system which includes the brain and the spinal cord.

Question 6

chromatolysis

Answer 6

swelling and disintegration of neuronal cytoplasmic organelles especially in response to axonal injury.

Question 7

contusion

Answer 7

a bruise; an injury of a part without a break in the skin, characterized by swelling, discoloration, and pain.

Question 8

coup

Answer 8

a “blow” or injury at the site of impact; contre-coup - injury at the side opposite the impact.

Question 9

diffuse axonal injury

Answer 9

refers to a massive disruption of axonal integrity within the white matter of the brain, generally following severe head trauma.

Question 10

dura

Answer 10

thick connective tissue membrane that forms the outer layer of the meninges and protects the brain and spinal cord; the intra-cranial compartment is divided by rigid dural folds (falx and tentorium).

Question 11

encephalitis

Answer 11

inflammation of the brain.

Question 12

epidural

Answer 12

located on or over the dura mater.

Question 13

glia

Answer 13

cells that surround and support neurons in the central nervous system.

Question 14

gyrus (pl. gyri)

Answer 14

the prominent rounded folds of cerebral tissue which comprise the convoluted surface of the cerebral hemispheres.

Question 15

hematoma

Answer 15

a localized mass of blood, usually clotted, trapped in an organ, space, or tissue, resulting from a break in the wall of a blood vessel.

Question 16

hemiplegia (vs hemiparesis):

Answer 16

Paralysis (vs weakness) of one side of the body (often due to lesions on the opposite side of the brain).

Question 17

herniation

Answer 17

displacement of tissue across dural partitions or through openings in the skull; usually as a result of increased intracranial pressure (as a result of increased CSF volume, edema, hemorrhage, or tumor within the brain), e.g., transtentorial or uncal herniation where the medial aspect of the temporal lobe is compressed against the free margin of the tentorium.

Question 18

hydrocephalus

Answer 18

the build up of fluid within the cavities of the brain (ventricles); excess fluid increases the size of the ventricles and puts pressure on the brain which can lead to further damage.

Question 19

Lewy body

Answer 19

the characteristic round, eosinophilic, intracytoplasmic inclusions of Parkinson’s disease.

Question 20

meninges

Answer 20

refers to the three connective tissue membranes covering the brain and spinal cord (i.e. dura, arachnoid and pia).

Question 21

meningitis

Answer 21

inflammation of the meninges of the brain and the spinal cord.

Question 22

microglia

Answer 22

a type of glial cell of the central nervous system that can act as a phagocyte (i.e. can ingest cellular debris) and is involved in inflammatory responses.

Question 23

neurofibrillary tangles

Answer 23

cytoplasmic flame-shaped collections of abnormal cytoskeletal elements, consisting mostly of abnormally phosphorylated protein (tau, a microtubule-associated protein). Neurofibrillary tangles are an element in the pathogenesis of Alzheimer’s disease.

Question 24

neuron

Answer 24

nerve cell; the cell body and its various processes.

Question 25

neuronophagia

Answer 25

phagocytosis of dead neurons.

Question 26

oligodendroglia

Answer 26

a cell of the central nervous system that forms the myelin sheaths around nerve fibres.

Question 27

paraesthesia

Answer 27

an abnormal sensation which may be felt as a burning or tingling feeling (i.e. ‘pins and needles’).

Question 28

peripheral nervous system (PNS)

Answer 28

the part of the nervous system that is external to the brain and spinal cord from the nerve roots to their peripheral terminations.

Question 29

plaques

Answer 29

a small disk-shaped formation or growth; the senile plaques of Alzheimer’s disease consist of a core of extracellular amyloid surrounded by a crown of swollen neuronal processes (dystrophic neurites).

Question 30

prions

Answer 30

proteinaceous infectious agents; these agents consist exclusively of protein and cause infection by inducing changes in normal host proteins.

Question 31

Schwann cell

Answer 31

a cell of the peripheral nervous system which wraps around axons forming an insulating myelin sheath to improve nerve conductance.

Question 32

stroke

Answer 32

term denoting a sudden neurological impairment due to impaired cerebral blood flow. More precise categories include cerebral infarction and cerebral hemorrhage.

Question 33

subarachnoid

Answer 33

the space between the arachnoid and pial meningeal layers.

Question 34

subdural

Answer 34

the space between the dura and arachnoid meningeal layers.

Question 35

sulcus (pl. sulci)

Answer 35

the grooves located on the surface of the brain which divide adjacent gyri.

Question 36

Wernicke’s encephalopathy

Answer 36

a condition observed in chronic alcoholics primarily due to thiamine deficiency; it is characterized by confusion, ataxia, and extraocular palsies.

Question 37

Abnormal sensation:

Answer 37

Numbness, paraesthesia (pins and needles), loss of position sense or two point discrimination.

Question 38

Aphasia:

Answer 38

Loss of language function in which either understanding or expression of speech or both are affected. Due to a cortical lesion in the dominant hemisphere.

Question 39

Ataxia

Answer 39

Incoordination, disruption of smooth precision of movements. Cerebellar lesions are common causes of this.

Question 40

Hemianopsia

Answer 40

Loss of right or left visual field in both eyes. The responsible lesion must be located in visual pathways posterior to the optic chiasm.

Question 41

Paresis

Answer 41

or weakness results from disease of any of the elements in the motor pathway, comprised of the upper motor neuron in the motor cortex, lower motor neurons in the spinal cord and brain stem, peripheral nerves, and muscle. Tone (flaccid or spastic), reflexes, distribution of weakness and associated signs and symptoms help to determine the site of the lesion.

Question 42

Hemiplegia (vs hemiparesis):

Answer 42

Paralysis (vs weakness) of one side of the body (often due to lesions on the opposite side of the brain), respectively.

Question 43

Paraplegia (vs paraparesis):

Answer 43

Paralysis (vs weakness) of the legs, most commonly due to lesions in the spinal cord.

Question 44

Quadriplegia:

Answer 44

Paralysis of all four limbs; tetraplegia.

Question 45

Seizure

Answer 45

Transient disorder of cerebral function, often associated with a disturbance of consciousness, that is due to a sudden, brief, synchronous, excessive electrical discharge of cerebral neurons. Seizures may be of focal or generalized onset. Focal onset seizures can start in any part of the cerebral cortex, giving rise to motor, sensory, or psychological symptoms prior to alteration of consciousness. Many focal seizures are due to a lesion in the cerebral cortex (e.g. scar, stroke, tumor, etc.). Generalized seizures are characterized by loss of consciousness and tone from the onset, and often no abnormality can be found on anatomical examination of the brain.