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Flashcards in Pathology Deck (43):
1

What is a lesion?

A zone of localized dysfunction within the nervous system

2

What are the 2 classifications of lesions?

- Anatomic: Structural
- Physiologic: Dysfunction, but no structural lesion

3

What are symptoms?

Subjective sensations resulting from a disorder

4

What are signs?

Objective abnormalities detected on exam.

5

Is a headache a symptom or sign?

Symptom

6

Is hyperreflexia a symptom or sign?

Sign

7

What is a syndrome?

A constellation of signs and symptoms associated with each other, suggesting a common origin

8

What are negative and postive neurological manifestations of lesions?

Negative: Loss of function
Positive: Result from inappropriate exciitation

9

What neurological senses are required for gait?

- Sensory
- Cerebellar
- Visual
- Vestibular

10

Do neurogenic diseases tend to be more distal or more proximal?

- Distal

11

What type of distribution do neurogenic diseases tend to have?

- Glove/ stocking distribution

12

What are the 2 types of neurogenic diseases?

- Motor neuron
- Peripheral neuropathies

13

What are the 2 signs/ symptoms of neurogenic disease of the motor unit?

- Fasciculation (visible)
- Fibrillations (not visible)

14

What are "diseases of the muscle" called?

Myopathies

15

What is the primary problem of myopathies?

Muscle weakness

16

Do myopathies tend to be proximal or distal?

Proximal

17

What are muscular dystrophies?

Myopathies with special characteristics such as:
- Heredity
- Progressive weakness and wasting

18

Which muscle system tends to cause death in myopathies?

Respiratory system

19

What is a myotonic disorder?

An abnormality of the muscle fiber membrane

20

How is the muscle affected by a myotonic disorder?

- Marked delay in relaxation
- Increased stiffness for an extended period of time

21

What is the pathogenesis of Myansthenia Gravis?

- Autoimmune disorder where antibodies attach the acetycholine receptor

22

What is the progression of Myasthenia Gravis?

- Slow, progressive

23

How are the muscles affected by Myasthenia Gravis? What are the 2 major symptoms?

- Weakness is patchy, and not related to the distribution of any single nerve
- Weakness fluates
- Decreased muscular endurance

24

What age and gender are affected by Myasthenia Gravis?

- Any age
- More common in females

25

What is it called when the eye is half open (common in Myasthenia Gravis)?

Ptosis

26

At what level is the motor unit affected by Myasthenia Gravis?

The synapse

27

Describe the 4-step process of Wallerian Degeneration.

Less than 24 hours: Neurofilaments break up; axons break up into short lengths
Within 10 days: Myelin sheath breaks down into lipid droplets around axon
Within Month: Myelin denatures
Within 3 Months: Macrophages from endoneurium invage myelin sheath and axis cyclinder and phagocytize everything

28

Where are fat droplets found in relation to the lesion in Wallernian Degeneration?

- Distal to lesion
- One or 2 nodes proximal to lesion

29

What is chromatolysis?

- When an axon is damaged, the cell swells, nucleus swells, and protein substances move to one side producing protein, and sending it down to the site of injury

30

How are muscles and nerves affected when healing of an axon begin?

- Muscle is no longer innervated and atrophies
- Nerves synapsing on axon atrophy

31

What type of injury will cause Wallerian Degeneration/ Chromatolysis?

Axonotemesis

32

What must occur before healing of a nerve begins in the periphery?

- Degeneration/ myelin removal

33

What protective coating must remain for nerve eregeneration to occur?

Neurolemma

34

What are the structures that sprout from proximal nerves in a damaged peripheral nerve during healing?

- Filopodia

35

How do filopodia help a nerve regenerate?

- The filopodia attach to the schwann cell and provide a scaffolding for other filopodia to grow
- The filopodia then become myelinated

36

At what rate do nerve regenrate?

1 mm/day

37

What are 2 methods of neural plasticity in an axonal/ neuronal injury?

- An axon may shoot a collateral to plug a hole
- A glia cell may plug the hole

38

What is apoptosis?

Orderly, genetically programmed cell death

39

What synaptic stripping?

- Synaptic terminals withdraw from neuron, and are replaced by processes of glia cells

40

What substance from schwann cells attract neurons?

- Chemotropic factors

41

Why may a neurolemma or cell die in the periphery?

- If the filopodia do not reach a schwann cell

42

What inside the perineurium can prevent the regenerating axons from going astray?

Inhibitory molecules

43

What 4 factors contribute to poor central NS regeneration?

- Glial scars
- Growth inhibition from Oligodendroglia
- Do not have trophic factors required for regeneration
- No neurolemma sheath