Pathology

Question 1

what are the 2 questions you should try to answer?

Answer 1

1- where is the lesion

2- what is (are) the lesions
vascular, tumor, traumatic

Question 2

what is a lesion?

Answer 2

refers to a zone of localized dysfunction w/in the NS

anatomic- structural damage

physiologic- dysfunction in absence of structural lesions

Question 3

symptoms=

Answer 3

subjective sensations resulting from the disorder

“I have a headache”

Question 4

signs=

Answer 4

objective abnormalities detected on exam

“hyperactive reflexes”

Question 5

syndrome=

Answer 5

a constellation of signs and symptoms associated with each other and suggest a common origin

Question 6

neurologic manifestations may be ___ or ___

Answer 6

negative- loss of function

position- result from inappropriate excitation (seizure)

Question 7

diagnosis depends on:

Answer 7

history**
observation of behavior **
time course
neuroexam
neuro imaging techniques

Question 8

neuro exam:

Answer 8

history

cognitive function
-level of consciousness (confusion, alertness, etc)

gait
requires coordination of sensory, cerebellar, visual and vestibular functions

cranial nerves

motor system
weakness, endurance, side, fine finger movements, reflexes

sensory system
distribution

imaging
CT, MRI, xrays, PET, SPECT, etc

EMG

(PNS- check myotome and dermatome)
(CNS- cranial nerve testing- motor and sensory- some sort of provocative action)

Question 9

what are the different diseases of the motor unit?

Answer 9

neurogenic diseases

myopathies

muscular dystrophies

myotonic disorders

disease of the synapse

Question 10

neurogenic diseases tend to be more:

Answer 10

distal (glove- stocking distribution (hands/feet))

Question 11

what are the 2 types of neurogenic diseases?

Answer 11

1- motor neuron

2-peripheral neuropathies

Question 12

what are s/s of neurogenic diseases?

Answer 12

muscular spontaneous firing

• fasciculation
• fibrillations

Question 13

neurogenic in the PNS

Answer 13

neuropathies

Question 14

myopathies=

Answer 14

diseases of muscle

weakness is primary problem

tends to be proximal

Question 15

muscular dystrophies=

Answer 15

myopathies with special characteristics

• heredity
• progressive weakness and wasting

**first thing to go that causes death is respiratory system

Question 16

myotonic disorders:

Answer 16

abnormality of muscle fiber membrane

leads to marked delay in relaxation= increase stiffness

Question 17

what is myasthenia gravis?

Answer 17

a disease of the synapse

“ALS”

autoimmune disorder-antibodies attack ACh receptors (Ach receptors on post-synaptic side disappear and there is no where for ACh to bind)

slow progressive course

weakness is patchy and does not confirm to the distribution of any single nerve

fluctuating weakness and decrease endurance are the major complaints

any age and more common in females

die from respiratory failure- too weak to breath (diaphragm)

Question 18

classification of myasthenia gravis:

Answer 18

class I: eye muscle weakness

class II: eye muscle weakness; mild ms weakness
IIa: limb /axial muscles
IIb: bulbar/resp muscles

Class III: eye ms weakness; moderate ms weakness
IIIa: limb/axial ms
IIIb: bulbar/resp ms

Class IV: eye ms weakness; severe ms weakness
IVa: limb/axial ms
IVb: bulbar/resp ms

Class V: intubation needed to maintain airway

Question 19

peripheral nerve injury:

Answer 19

chromatolysis= dissolution of neuron cell bodies

wallerian degeneration =

• 1 day=neurofilaments break up; axons get shorter
• 10 days= myelin sheaths breaks into lipid droplets around axon
• month= myelin gets denatured chemically
• 3 months= macrophages invade degenerating myelin and phagocytose debris

Question 20

nerve regeneration:

Answer 20

the single nerve fiber will “sprout” to form a regenerating unit. at the tip of each sprout is a growth cone with multiple filopodia. these filopodia will adhere to the basal lamina of the Schwann cell. the Schwanna cells are intimately associated with the regenerating fibers.

as the regenerating unit matures, the individual sprouts become myelinated. regeneration occurs along the basal lamina of the Schwann cells

Question 21

CNS and PNS go through same process_____ degeneration

Answer 21

wallerian degeneration

Question 22

axotomy in the PNS

Answer 22

not only affects injured neuron but also its synaptic partners and neighboring cells

the axon distal to the cut will degenerate and so will the myelin surrounding it. The Schwann cells will stay intact. axon degenerates and breaks down into little pieces; neurolemma sheaths stay intact; from cut to synapse the axon is gone. phagocytes clean out neurolemma sheath so its a clean tube.

proximally, the axon will also regenerate/retract one or 2 internodes and regenerates.
cell body starts producing lots of protein

Question 23

transneuronal degeneration=

Answer 23

atrophy of certain neurons after interruption of afferent axons or death of other neurons to which they send their efferent output.

anterograde- “dying forward”
retrograde- “dying backward”

Question 24

transneuronal atrophy

Answer 24

CNS neurons have a trophic effect upon each other

Question 25

apoptosis=

Answer 25

a mechanism of orderly, genetically programmed cell death

Question 26

synaptic stripping=

Answer 26

when synaptic terminals withdraw from the neurons and are replaced by the processes of glial cells

Question 27

peripheral regeneration:

Answer 27

Good

chemotropic factors secreted by schwann cells attract axons
-schwann cells give off facilitory factors that help peripheral nerve regeneration

failure to contract a schwann cell causes a neuroma and cell death

adhesive molecules within the distal stump promote axon growth along cell membranes

inhibitory molecules in the perineurium prevent the regenerating axons from going astray

has neurolemma sheath

surgery-3 weeks

Question 28

the more proximal the injury the higher the change the nerve will:

Answer 28

die

a lot of length of nerve needs to be regenerated

Question 29

central regeneration:

Answer 29

poor

glial scare

growth inhibition by oligodentroglia
-neurite growth inhibitors (in myelin)

generally don’t have the trophic factors required for successful regeneration
-no neurolemma sheath