Peripheral Nerves and Skeletal Muscles

Question 1

what do afferent nerves do

Answer 1

relaying sensation away from the body towards the CNS

Question 2

what do efferent nerves do

Answer 2

send out commands from the CNS to the body

Question 3

what does the epineurium do

Answer 3

enclose the entire nerve

Question 4

what does the perineurium do

Answer 4

groups subsets of axons into fascicles

Question 5

what does the endoneurium do

Answer 5

surrounds individual nerve fibers

Question 6

what do Schwann cells do

Answer 6

produce myelin sheath

Question 7

what are nodes of Ranvier

Answer 7

unmyelinated gaps

Question 8

what is Wallerian degeneration

Answer 8

when axons degenerate over time - leads to a slow onset and reduces signal strength

Question 9

what is a traumatic neuroma

Answer 9

pseudo tumor produced when stumps of a severed nerve begin to proliferate

Question 10

which two things can cause a neuronopathy (destruction of neurons)

Answer 10

infections
toxins

Question 11

what is Guillain-Barré syndrome

Answer 11

demyelinating of the peripheral nerves caused by some kind of virus

leads to ascending paralysis which can affect the respiratory system

Question 12

what is the most common chronic acquired inflammatory peripheral neuropathy

Answer 12

chronic inflammatory demyelinating polyradiculoneuropathy

Question 13

what is chronic inflammatory demyelinating polyradiculoneuropathy

Answer 13

condition that affects nerves and their roots

is not caused by a virus

responds to steroids

Question 14

in which condition would you see an “onion bulb”

Answer 14

chronic inflammatory demyelinating polyradiculoneuropathy

Question 15

what is an “onion bulb”

Answer 15

area of demyelination and remyelination seen in chronic inflammatory demyelinating polyradiculoneuropathy

Question 16

what is vasculitis

Answer 16

noninfectious inflammation of blood vessels that can damage peripheral nerves

Question 17

what is the other name for Leprosy

Answer 17

Hansen disease

Question 18

how are nerves affected in Lyme disease

Answer 18

facial nerve palsies

Question 19

which type of nerve is most affected in those with HIV/AIDS

Answer 19

peripheral

Question 20

what is the Varicella-Zoster Virus (shingles)

Answer 20

activation of latent chickenpox virus

causes degeneration of the axons of the peripheral nerves

Question 21

which two nerves are most commonly involved in the Varicella-Zoster Virus (shingles)

Answer 21

1.) thoracic
2.) trigeminal

Question 22

what is the most common cause of peripheral neuropathy

Answer 22

diabetes

Question 23

what are the two most common factors of diabetic peripheral neuropathy

Answer 23

1.) atherosclerosis of vessels
2.) destruction of peripheral nerves

Question 24

20-40% of those with diabetic peripheral neuropathy can also have which four conditions of the autonomic nervous system

Answer 24

1.) postural hypotension
2.) difficulty emptying bladder
3.) sexual dysfunction
4.) lumbosacral radiculoplexus neuropathy

Question 25

what is Myasthenia gravis

Answer 25

autoimmune disease associated with autoantibodies against acetylcholine receptors causes double vision and affects the respiratory system

Question 26

which gender is more affect by Myasthenia gravis

Answer 26

females 2:1

Question 27

what additional condition is associated with Myasthenia gravis

Answer 27

thymic abnormalities (enlarged)

Question 28

what is Lambert-Eaton Myasthenic Syndrome

Answer 28

autoimmune disorder where antibodies block acetylcholine release by inhibiting a presynaptic calcium channel

Question 29

50% of those with Lamber-Eaton Myasthenic Syndrome also have what

Answer 29

an underlying malignancy like small cell neuroendocrine tumor of the lung

Question 30

what is Botulism

Answer 30

disease caused by exposure to Botox blocks release of acetylcholine

Question 31

which disease can young children get from ingesting honey

Answer 31

Botulism

Question 32

what is the organization of the skeletal muscle from largest to smallest

Answer 32

muscle fascicle fiber sarcolemma myofibrils

Question 33

what is a myofibril

Answer 33

contractile unit of muscle

Question 34

what is myosin

Answer 34

creates thick filament contractile proteins

Question 35

what is actin

Answer 35

creates thin filament contractile proteins

Question 36

which type of muscle fiber is a slow twitch

Answer 36

type 1

Question 37

which type of muscle fiber is a fast twitch

Answer 37

type 2

Question 38

what is a neurogenic injury

Answer 38

injury that causes disruption of muscle innervation leads to fiber atrophy, giving them a flattened, angular shape

Question 39

what are the three morphologic changes of a myopathic injury

Answer 39

1.) segmental myofiber degeneration and regeneration 2.) myofiber hypertrophy 3.) cytoplasmic inclusions

Question 40

what is dermatomyositis

Answer 40

autoimmune inflammatory myopathy that affects the skin and skeletal muscles leads to discoloration of the skin, nail folds, eyelids, and gums

Question 41

what is seen histologically in dermatomyositis

Answer 41

myofiber atrophy at the edges of the fascicles (perifascicular atrophy)

Question 42

what is seen histologically in inclusion body myositis

Answer 42

rimmed vacuoles

Question 43

what is the most common inflammatory myopathy in patients over 65 years of age

Answer 43

inclusion body myostitis

Question 44

what is seen histologically in polymyositis

Answer 44

necrotic, regenerating, and atrophic myofibers in a patchy distribution

Question 45

what are the three main types of inflammatory myopathies

Answer 45

1.) dermatomyositis 2.) inclusion body myositis 3.) polymyositis

Question 46

what is the most common cause of a drug myopathy

Answer 46

cholesterol lowering drugs like statins

Question 47

which type of toxic myopathy is seen with corticosteroid therapy

Answer 47

ICU myopathy (myosin deficient myopathy)

Question 48

the most common muscular dystrophies are _____

Answer 48

X-linked

Question 49

what is the most common type of muscular dystrophy

Answer 49

Duchenne muscular dystrophy

Question 50

what is the main cause of muscular dystrophy

Answer 50

lack of the structural protein dystrophin

Question 51

what is the second most common type of muscular dystrophy

Answer 51

Becker muscular dystrophy

Question 52

what is myotonic dystrophy

Answer 52

multi system genetic disorder associated with muscle weakness, cataracts, and cardiomyopathy

Question 53

where do peripheral nerve sheath tumors come from

Answer 53

Schwann cells

Question 54

what is a schwannoma

Answer 54

benign tumor of the Schwann cells of the peripheral nerves

Question 55

what are the three histologic hallmarks of a schwannoma

Answer 55

1.) Antoni A 2.) verocay bodies 3.) Antoni B

Question 56

what is an Antoni A

Answer 56

dense eosinophilic area within a schwannoma

Question 57

what is a verocay body

Answer 57

nuclear-free zones within a schwannoma

Question 58

what is an Antoni B

Answer 58

hypocellular area with myxoid extracellular matrix seen in a schwannoma

Question 59

schwannomas of the cranium (acoustic neuroma) most commonly affects which nerve

Answer 59

vestibular branch of the eighth nerve

Question 60

what is a schwannoma of the cranium called

Answer 60

acoustic neuroma

Question 61

what is a superficial cutaneous neurofibroma

Answer 61

small unencapsulated nodules that arise in the dermis and fat

Question 62

what are diffuse neurofibromas

Answer 62

large, plaque like lesions of the skin

Question 63

what are plexiform neurofibromas

Answer 63

associated with nerve roots or large nerves resemble a bag of worms as they grow and entrap axons

Question 64

what is most commonly seen histologically in a malignant peripheral nerve sheath tumor (MPNST)

Answer 64

arrangement of spindle cells

Question 65

neurofibromatosis type 1 is caused by a genetic alteration of which chromosome

Answer 65

17

Question 66

neurofibromatosis type 2 is caused by a genetic alteration of which chromosome

Answer 66

22

Question 67

which three conditions are associated with neurofibromatosis type 1

Answer 67

1.) cafe au lait spots 2.) cutaneous neurofibromas 3.) Lisch nodules

Question 68

what is a lisch nodule

Answer 68

melanocytic hamartoma projecting from the surface of the iris

Question 69

lisch nodules are seen in which condition

Answer 69

neurofibromatosis type 1

Question 70

which two conditions are often associated with neurofibromatosis type 2

Answer 70

1.) acoustic neuromas 2.) vestibular schwannomas