2Vm - Pathology - Final - Nervous System - Objectives

Front 1

What is the white matter composed of? (2)

Back 1

- Axons
- Supporting glial cells (including their processes)

Front 2

What is the gray matter composed of? (2)

Back 2

Primarily the neuronal cell bodies
- Also axons, dendrites, and glial cells (including their processes)

Front 3

What are Nissl bodies and what do they do?

Back 3

rERs in the neuronal cell bodies
- Synthesize NTs

Front 4

What is the term for the dense meshwork of axons and glial cell processes found in the gray matter?

Back 4

Neuropil

Front 5

Term for the change in the cell body following axonal injury

Back 5

Central chromatolysis

Front 6

Histologic changes of central chromatolysis (3)

Back 6

- Swelling of cell body
- Dispersal of Nissl substance
- Eccentric positioning of nucleus

Front 7

Swelling, fragmentation, dissolution, and removal of affected axonal segments by MPs

Back 7

Wallerian degeneration

Front 8

Which nervous system subset regenerates damaged axons?

Back 8

Peripheral

Front 9

Histologic change of ischemic cell change (3)

Back 9

Cell body shrinks
Cytoplasm stains eosinophilic
Nucleus is triangular shaped

Front 10

Death of one neuron causes another neuron in the chain to die.

Back 10

Transneuronal degeneration

Front 11

5 functions of astrocytes in supporting the CNS

Back 11

- Structural support of CNS
- Influence on blood-brain barrier formation
- Insulation of synaptic contacts on neuron
- Biochemical functions
- Immunoregulation

Front 12

What do astrocytes form in relationship to the brain and SC?

Back 12

Innermost subpial covering called the glia limitans

Front 13

Name of the subpial covering of brain and SC formed by astrocytes

Back 13

Glia limitans

Front 14

What are the myelin forming cells within the CNS?

Back 14

Oligodendroglia

Front 15

Proliferation of glial cells

Back 15

Gliosis

Front 16

3 histologic changes that happen to astrocytes with severe injury

Back 16

- Swelling
- Loss of processes
- Degeneration

Front 17

What happens when astrocytes become reactive?

Back 17

Astrocytes enlarge without loss of processes

Front 18

What happens during astrocytosis?

Back 18

Variable proliferation of astrocytes

Front 19

Glial scar (define)

Back 19

Dense network of astrocyte processes formed from astrocytosis

Front 20

What remains to evidence astrocytic proliferation due to injury?

Back 20

Increase in number of nuclei in the cell body

Front 21

What cell type myelinates the peripheral nervous system?

Back 21

Schwann cells

Front 22

Origin of microglia

Back 22

Derived from monocytes that migrate to the brain during late embryonic and early postnatal periods

Front 23

Function of microglia (3)

Back 23

- Removal of apoptotic cells from developing and remodeling of CNS during embryogenesis
- Regulation of inflammation
- Transformation into phagocytic macrophages

Front 24

What are gitter cells?

Back 24

Phagocytic macrophages in the CNS that differentiated from microglia

Front 25

What forms the choroid plexus?

Back 25

Modified ependymal cells within the ventricles

Front 26

What produces CSF?

Back 26

Choroid plexi

Front 27

What is the term for a defective closure of the neural tube during development?

Back 27

Dysgraphia

Front 28

What is the term for a total absence of the brain?

Back 28

Anencephaly

Front 29

What is the term for an absence or rudimentary development of the cereberal hemispheres?

Back 29

Prosencephalic hypoplasia

Front 30

What is the term for a midline bone defect of the cranium through which meningeal and/or brain tissue protrudes?

Back 30

Cranium bifidum

Front 31

What is the term for a sac outside the head that's covered with skin and lined by meninges?

Back 31

Meningocele

Front 32

What is the term for a sac outside the head that's lined with meninges and accompanied by brain material?

Back 32

Meningoencephalocele

Front 33

What is the term for a defect in the dorsal vertebral column through which the spinal meninges and/or spinal cord may herniate?

Back 33

Spina bifida

Front 34

What is spina bifida with no herniation?

Back 34

Spina bifida occulta

Front 35

What is spina bifida with herniation of the meninges?

Back 35

Meningocele

Front 36

What is spina bifida with herniation of meninges and spinal cord?

Back 36

Meningomyelocele

Front 37

Which dog species is predispositioned towards spina bifida?

Back 37

English Bulldogs

Front 38

Which cat species is predispositioned towards spina bifida?

Back 38

Manx

Front 39

What is a dermoid sinus?

Back 39

Development caused by incomplete seperation of skin from neural tube

Front 40

Dog breed that's predispositioned towards dermoid sinuses

Back 40

Rhodesian Ridgeback

Front 41

Term for the condition of the folds that are normally present in the cerebral hemispheres being absent

Back 41

Lissencephaly

Front 42

Term for an increased accumulation of CSF

Back 42

Hydrocephalus

Front 43

Two types of hydrocephalus

Back 43

- Noncommunicating
- Communicating

Front 44

Two types of noncommunicating/communicating hydrocephalus

Back 44

- Congenital
- Acquired

Front 45

What causes noncommunicating hydrocephalus?

Back 45

Obstruction within the ventricular system prior to exit of the CSF from the lateral apertures of the fourth ventricle

Front 46

What's the most common type of noncommunicating hydrocephalus?

Back 46

Congenital

Front 47

What breeds is a congenital noncommunicating hydrocephalus most common in?

Back 47

Toy breeds

Front 48

What is a congenital noncommunicating hydrocephalus associated with?

Back 48

- Stenosis of mesencephalic aquieduct
- Fusion of rostral colliculi

Front 49

What's a unique lesion associated with congenital noncommunicating hydrocephalus?

Back 49

Doming of the cranium

Front 50

3 causes of an acquired noncommunicating hydrocephalus

Back 50

Obstruction of:
- Lateral apertures of the fourth ventricle
- Mesencephalic aqueduct
- Interventricular foramen

Front 51

2 causes of obstructions associated with an acquired noncommunicating hydrocephalus

Back 51

- Inflammation
- Neoplasia

Front 52

What causes a communicating hydrocephalus?

Back 52

Obstruction preventing drainage of CSF into venous system

Front 53

How does a congenital communicating hydrocephalus occur?

Back 53

Maldevelopment of the arachnoid villi

Front 54

How does an acquired communicating hydrocephalus occur?

Back 54

Inflammation or neoplasia of the subarachnoid space and arachnoid villi

Front 55

4 lesions common to hydrocephalus (communicating and noncommunicating)

Back 55

- Doming of cranium
- Enlargement of ventricular system
- Flattening of surface gyri
- Posterior postioning of brain with herniation of the cerebellum into the foramen magnum

Front 56

What is the spinal cord equivalent of hydrocephalus?

Back 56

Hydromyelia

Front 57

Cavitation of the spinal cord parenchyma over several spinal segments

Back 57

Syringomyelia

Front 58

Difference between hydranencephaly and hydrocephaly

Back 58

Hydraencephaly is characterized by cavitation of the area normally occupied by the white matter of the cerebral hemispheres, in which the ventricles expand into

Hydrocephaly is more of a forceful expansion of the ventricles

Front 59

What lesion is present in hydrocephaly that's not in hydrancephaly? (2)

Back 59

- Doming of cranium
- Obstruction of ventricular system

Front 60

Underlying mechanism for hydrancephaly

Back 60

Lack of development of subependymal progenitor cells that are responsible for formation of the cerebral parenchyma in fetuses

Front 61

What condition often accompanies hydrancephaly?

Back 61

Arthrogryposis

Front 62

Two conditions caused by fetal viral infections

Back 62

- Hydrancephaly
- Cerebellar hypoplasia

Front 63

What is cerebellar hypoplasia characterized by?

Back 63

Reduction in size of cerebellum

Front 64

4 viruses at cause cerebellar hypoplasia

Back 64

- Feline parvovirus (Panleukopenia)
- BVD virus
- Border disease virus (sheep)
- Hog cholera virus (pig)

Front 65

What are lysosomal storage diseases characterized by?

Back 65

IC accumulation of material within lysosomes

Front 66

What causes lysosomal storage diseases?

Back 66

Defect in normal enzymatic degradation process

Front 67

Underlying lesion of arthrogryposis

Back 67

Loss of neurons in the ventral horn of the spinal cord

Front 68

4 ways that the normal enzymatic degradation process can become altered

Back 68

- Lack of enzyme synthesis
- Production of inactive enzymes
- Lack of enzyme activator proteins
- Failure of enzyme to compartmentalize in the lysosome

Front 69

Two conditions that can lead to a hepatic encephalopathy

Back 69

- Portosystemic shunts
- Diffuse acquired liver disease

Front 70

What's the underlying cause of hepatic encephalopathy?

Back 70

Liver's ability to convert ammonia to urea is impaired

Front 71

5 neurologic signs of hepatic encephalopathy

Back 71

- Altered behavior
- Depression
- Head pressing
- Blindness
- Collapse

Front 72

Gross lesions of hepatic encephalopathy

Back 72

None visible

Front 73

2 microscopic lesions of hepatic encephalopathy

Back 73

- Spongiform change (vacuolization) of white matter
- Enlarged astrocytes

Front 74

Term for underdevelopment of myelin

Back 74

Hypomyelinogenesis

Front 75

Term for abnormal development of myelin

Back 75

Dysmyelination

Front 76

Term for degeneration of myelin

Back 76

Demyelination

Front 77

What causes a primary demyelination?

Back 77

Myelin sheath is selectively destroyed with the axon remaining intact

Front 78

What causes a secondary demyelination?

Back 78

Myelin sheath is destroyed secondary to axon destruction
- IE in Wallerian degeneration

Front 79

Axon degeneration

Back 79

Axonapathy

Front 80

Premature death of neuronal cell populations

Back 80

Abiotrophy

Front 81

What plant related toxicity affects cattle?

Back 81

- Mesquite toxicity

Front 82

2 lesions of mesquite toxicity

Back 82

- Vacuolation of trigeminal nucleus neurons
- Masticatory muscle paralysis

Front 83

What plant related toxicity affects horses?

Back 83

- Yellow star thistle toxicity
- Fusarium moniliforme fungal toxicity (in corn)

Front 84

What disease does Fusarium moniliforme cause in horses?

Back 84

Leukoencephalomalacia
- 'Moldy corn poisoning'

Front 85

Pathogenesis of Locoweed toxicity

Back 85

- Inhibits a-mannosidase
- Mannisol accumulates in cell as a result
- Cellular dysfunctions occur

Front 86

What disease is associated with a high COH diet?

Back 86

Polioencephalomalacia

Front 87

A decrease in what vitamin is associated with polioencephalmalacia?

Back 87

Thiamine

Front 88

Gross lesions of polioencephalomalacia (3)

Back 88

- Swollen brain
- Flattened gyri
- Fluoresces under UV light

Front 89

Which disease process fluoresces under UV light?

Back 89

Polioencephalmalacia

Front 90

Histologic lesions of polioencephalomalacia (4)

Back 90

- Ischemic neuronal necrosis in the cerebral cortex (laminar cortical necrosis)
- Shrunken neurons
- Eosinophilic cytoplasm
- Pyknotic nuclei

Front 91

What two species are most commonly affected by lead poisoning?

Back 91

- Cattle
- Dogs

Front 92

What two toxicities resemble polioencephalmalacia?

Back 92

- Lead
- Mercury

Both have laminar cortical necrosis

Front 93

Difference between extrinsic and intrinsic trauma

Back 93

Extrinsic is caused by stuff in the environment (car accidents, falls).

Intrinsic is caused by physiologic processes.

Front 94

4 intrinsic causes of CNS injury

Back 94

- Vertebral malformations
- IVD rupture
- Parasite migration
- Space occupying lesions

Front 95

Factors affecting severity of trauma to CNS

Back 95

- Stability of head
- Force of object striking the head
- Smaller object produces focal, deeper injury
- Large object produces shallow but diffuse injury

Front 96

Things protecting the brain:
- Rigidity of cranium
- Round shape of skull
- Structure of cranial bones (bilayer)
- Cranial sutures
- Sinuses
- Ridges in floor of cranial cavity
- Meninges
- CSF

Back 96

Things protecting the spinal cord:
- Soft tissues that surround the vertebral column
- Cancellous bone of vertebrae
- IVDs that absorb shock
- Denticulate ligaments
- Vertebral ligaments
- Meninges
- CSF

Front 97

Difference between a concussion and a contusion

Back 97

Concussion is characterized by a temporary loss of consciousness with recovery, has no gross appearance, and has diffuse brain injury

Contusion is characterized by a grossly detectable lesions that is more focal in nature and may be superficial or deep in the brain

Front 98

What term dictates a contusion that is located at the impact site?

Back 98

Coup contusion

Front 99

What term dictates a contusion that is located away from the impact site?

Back 99

Contrecoup contusion

Front 100

Four locations that hemorrhage may occur following trauma to the brain

Back 100

- Epidural space
- Subdural space
- Subarachnoid space
- Brain parenchyma

Front 101

What is an important sequela to CNS trauma and why?

Back 101

Swelling
- Causes damage because the brain and SC both are in fixed 'cases'

Front 102

Two species that cervical stenotic myelopathy occurs in

Back 102

- Horses
- Dogs

Front 103

What causes cervical stenotic myelopathy?

Back 103

Malformation or malarticulation of the cervical vertebral bodies that results in a stenosis of the vertebral canal and compression of the spinal cord

Front 104

What is the common name given to cervical stenotic myelopathy?

Back 104

'Wobbler syndrome'

Front 105

What is the characteristic sign of Wobbler Syndrome?

Back 105

Ataxia

Front 106

2 breeds of dogs that cervical stenotic myelopathy occurs most frequently in

Back 106

- Great Dane
- Doberman Pinscher

Front 107

How does IVD cause neurologic deficits?

Back 107

Disks bulge into vertebral canal and slowly produce neurologic signs
- Acute ruptures cause more severe deficits

Front 108

Breeds that are predispositioned towards IVD

Back 108

Chondrodystrophoid breeds

Front 109

4 space occupying lesions

Back 109

- Neoplasms
- Granulomas
- Cysts
- Abscesses

Front 110

2 sources of tumors that can put pressure on the brain

Back 110

- Meninges (meningioma)
- Skull

Front 111

2 nematode species who's larvae cause CNS damage

Back 111

- Paraelaphostrongylus tenuis
- Baylisascaris procyonis

Front 112

Two reasons animals aren't as likely to suffer trauma as humans are

Back 112

- Animals don't drive cars (very well) nor do other trauma-inducing activities that humans do
- Animals have more extensive frontal sinuses and better developed temporal muscles

Front 113

What is the most susceptible CNS cell to ischemia?

Back 113

Neurons

Front 114

List the CNS cells in order from most to least susceptible to ischemia (5)

Back 114

- Neurons
- Oligodendrocytes
- Astrocytes
- Microglia
- Endothelial cells

Front 115

Order of neuronal population death during ischemia from first to last (3)

Back 115

- Neurons of cerebral cortex
- Neurons of basal ganglia
- Motor neurons of spinal cord

Front 116

Underlying mechanism of vasogenic edema

Back 116

Breakdown of BBB

Front 117

What's the most frequently occurring edema of the CNS?

Back 117

Vasogenic

Front 118

Which part of the CNS does vasogenic edema most often involve?

Back 118

White matter

Front 119

3 gross changes associated with vasogenic edema

Back 119

- Swelling
- Softness
- Flattened gyri

Front 120

Three locations that the brain can herniate

Back 120

- Subfalcine area
- Transtentorial area
- Foramen magnum

Front 121

What is cytotoxic edema characterized by?

Back 121

Fluid accumulation within astrocytes and astrocytic processes

Front 122

Mechanism of cytotoxic edema

Back 122

Disruption of osmoregulation due to:
- Depletion of energy stores
- Failure of Na-K ATPase pumps

Front 123

4 things that can cause cytotoxic edema

Back 123

- Ischemia/hypoxia
- Nutritional deficiencies
- Toxins
- Inherited metabolic disorders

Front 124

Area of the CNS affected by cytotoxic edema

Back 124

Gray matter

Front 125

Microscopic appearance of cytotoxic edema

Back 125

Space around neurons and capillaries

Front 126

Infarction (define)

Back 126

Necrosis of a tissue following obstruction of arterial circulation

Front 127

Why is sudden infarction worse than gradual infarction?

Back 127

Gradual infarction allows time for anastomosis' to occur

Front 128

Malacia (define)

Back 128

Cavitation and softening of areas affected by cerebral infarction

Front 129

Histologically, what are two features of areas affected by acute infarction?

Back 129

- Neuronal degeneration
- Pallor of tissue

Front 130

Histologically, what are three features of areas affected by chronic infarction?

Back 130

- Liquefactive necrosis
- Accumulation of gitter cell
- Glial scarring

Front 131

What does fibrocartilagenous embolic myelopathy most often occur in?

Back 131

Large dog breeds

Front 132

What breeds of dogs are not affected by fibrocartilagenous embolic myelopathy?

Back 132

Chondrodystrophoid breeds

Front 133

Suspected source of embolism in fibrocartilagenous embolic myelopathy

Back 133

IVD

Front 134

Cause of Feline ischemic encephalopathy

Back 134

Intracranial migration of Cuterebra spp. flies

Front 135

Suspected mechanism of Neonatal maladjustment syndrome

Back 135

Hypoxia during parturition

Front 136

Two CNS disease processes that fluoresce under UV light

Back 136

- Neonatal maladjustment syndrome
- Polioencephalomalacia

Front 137

4 symptoms of Neonatal maladjustment syndrome in foals

Back 137

- Failure to suckle
- Aimless wandering
- Seizure
- Barking

Front 138

2 colloquial terms for Neonatal maladjustment syndrome

Back 138

'Dummy foal'
'Barker foal'

Front 139

Arteriosclerosis (define)

Back 139

Thickening and loss of elasticity of arterial walls

Front 140

Two types of Arteriosclerosis

Back 140

- Lipid
- Non-lipid

Front 141

What is non-lipid Arteriosclerosis characterized by? (2)

Back 141

- Fibrosis
- Mineralization

Front 142

What form of Arteriosclerosis is normal in aging animals?

Back 142

Non-lipid

Front 143

What is the lipid form of Arteriosclerosis called?

Back 143

Atherosclerosis

Front 144

4 things that form the BBB

Back 144

- Endothelial cells with tight junctions
- Basement membrane
- Astrocyte foot processes
- Pericytes

Front 145

3 differences of the CNS capillaries compared to peripheral capillaries

Back 145

- Decreased pinocytotic vesicles
- Lack fenestrations
- Lack intercellular clefts

Front 146

5 routes infectious agents may use to spread to the CNS

Back 146

- Hematogenous
- Within the axon's axoplasm
- From olfactory mucosa that has nerves synapsing with CNS
- Direct spread following trauma
- Various pericranial and perivertebral infections

Front 147

4 ways that infectious agents can spread within the CNS

Back 147

- Within interstitium
- Within neurons, neural processes, and neuroglia
- Through infected leukocytes
- Through the CSF

Front 148

Inflammation of the brain

Back 148

Encephalitis

Front 149

Inflammation of the meninges

Back 149

Meningitis

Front 150

Inflammation of the spinal nerve roots

Back 150

Radiculitis

Front 151

Inflammation of the peripheral ganglia

Back 151

Ganglionitis

Front 152

Inflammation of the peripheral nerves

Back 152

Neuritis

Front 153

Prefix used to indicate inflammation that occurs in the gray matter

Back 153

Polio-

Front 154

Prefix used to indicate inflammation that occurs in the white matter

Back 154

Leuko-

Front 155

Why are neonatal ruminants the most susceptible to meningitis?

Back 155

Prone to septicemia from unsanitary environment and failure of passive transfer

Front 156

What is listeriosis commonly associated with?

Back 156

Feeding of improperly prepared silage

Front 157

Where are Listeriosis lesions concentrated?

Back 157

Brain stem

Front 158

What do listeriosis lesions consist of? (2)

Back 158

- Necrosis
- Leukocyte accumulation

Front 159

Morphologic distribution of listeriosis lesions

Back 159

Multifocal

Front 160

What is an example of a hyphal fungus?

Back 160

Aspergillus

Front 161

What do hyphal fungal cause in CNS? (3)

Back 161

- Vasculitis
- Necrosis
- Inflammation

Front 162

Most common systemic dimorphic fungi that infects the CNS

Back 162

Cryptococcus neoformans (cryptococcosis)

Front 163

How does cryptococcosis appear grossly?

Back 163

Meninges covered with a gelatinous, mucoid exudate

Front 164

6 histologic lesions of viral infections of the CNS

Back 164

- Perivascular cuffing
- Neuronal necrosis with phagocytosis
- Microglial proliferation
- Nonsuppurative meningitis
- Viral inclusion bodies
- Demyelination

Front 165

What's a characteristic intracytoplasmic inclusion bodies of Rabies?

Back 165

Negri bodies

Front 166

Pathogenesis of cryptococcosis

Back 166

Cryptococcus infects nasal cavity and then enters the cranium through the cribiform plate

Front 167

How do most protozoal infections enter the CNS?

Back 167

Hematogenously

Front 168

Most common protozoal neurologic disorder

Back 168

Equine protozoal myelitis

Front 169

Pathogenesis of rabies infection

Back 169

Virus replicates in muscle cells --> enters peripheral nerves --> travel up to SC --> reach brain

Front 170

One histologic lesion that rabies does not produce that other viral infections do

Back 170

Demyelination

Front 171

Causative agent of spongiform encephalopathies

Back 171

Prions

Front 172

Spongiform encephalopathy in sheep

Back 172

Scrapies

Front 173

Spongiform encephalopathy in cattle

Back 173

Bovine Spongiform encephalopathy

Front 174

Spongiform encephalopathy in deer

Back 174

Chronic wasting disease

Front 175

5 pathologic findings of Spongiform encephalopathies

Back 175

- Vacuolation of neurons
- Neuronal degeneration
- Astrocyte hypertrophy
- Astrocyte hyperplasia
- Perivascular amyloid deposition

Front 176

What is the most common primary neuroectodermal tumor of the CNS?

Back 176

Astrocytoma

Front 177

What is the malignant form of an astrocytoma known as?

Back 177

Glioblastoma multiforme

Front 178

What is the second most commonly occuring neoplasm of the CNS?

Back 178

Oligodendroglioma

Front 179

What is an oligodendroglioma characterized by? (2)

Back 179

- Well demarcation
- Gelatinous consistency

Front 180

What is an astrocytoma characterized by?

Back 180

Poorly demarcated margin because the invading tumor cells blend gradually with normal tissue

Front 181

Two gross morphological signs that a glioblastoma multiforme causes that an astrocytoma does not

Back 181

- Hemorrhage
- Necrosis

Front 182

3 interventricular tumors

Back 182

- Choroid plexus papillomas
- Oligodendrogliomas
- Ependyomas

Front 183

What do ependyomas arise from?

Back 183

Ventricular system
- Rare

Front 184

What do choroid plexus papillomas arise from?

Back 184

Fourth ventricle
- Cerebromedullary angle is common site

Front 185

What may be a sequella of choroid plexus papillomas?

Back 185

Hydrocephalus if the tumor blocks CSF flow

Front 186

What is a highly malignant tumor that arises from pluripotential neuroectodermal cells?

Back 186

Primitive Neuroectodermal Tumors (PNETS)
- Rare

Front 187

What's the most common primary mesenchymal tumor of the nervous system?

Back 187

Meningiomas

Front 188

What's the most common primary CNS neoplasm in cats?

Back 188

Meningiomas

Front 189

What can meningiomas cause?

Back 189

Pressure atrophy of adjacent nervous tissue

Front 190

3 types of secondary neoplasms common in dogs

Back 190

- Malignant melanomas
- Hemangiosarcomas
- Carcinomas

Front 191

Two species affected by a CNS lymphoma

Back 191

- Cats
- Cattle

Front 192

What does a CNS lymphoma most often present as?

Back 192

Epidural mass in vertebral canal

Front 193

Example of an invasive secondary neoplasm

Back 193

Nasal adenocarcinomas

Front 194

3 examples of a hematogenous secondary neoplasm

Back 194

- Malignant melanomas
- Hemangiosarcomas
- CNS lymphomas

Front 195

Two clinical signs of spinal nephroblastomas

Back 195

- Ataxia
- Paraparesis

Front 196

How does a spinal nephroblastoma cause symptoms?

Back 196

Applies pressure directly to SC

Front 197

Where does a spinal nephroblastoma occur?

Back 197

Between T10 and L2 inside the dura mater
- So intradurally and extramedullary

Front 198

Most common tumor arising in peripheral nerves

Back 198

Schwannoma

Front 199

Malignant form of schwannoma

Back 199

Malignant peripheral nerve sheath tumors

Front 200

What are tumors of the PNS common in?

Back 200

Aged cattle
- Incidental findings at slaughter