Chapter 12 Workbook Questions Flashcards
Signs and symptoms in a myotomal and dermatomal distribution indicate that the lesion is in what region of the nervous system?
Signs and symptoms in a myotomal and dermatomal distribution indicate that the lesion is in the spinal region.
Axons to extrafusal muscle fibers
Name the classification of the listed axons
Aα
Axons to intrafusal muscle fibers
Name the classification of the listed axons
Aγ
Axons that convey sensory information perceived as pain and temperature
Name the classification of the listed axons
Aδ or C
Axons that convey sensory information perceived as touch and pressure
Name the classification of the listed axons
Ia
What is the most functionally important branch of the cervical plexus?
A. Branch to the sternocleidomastoid muscle
B. Branch to the biceps brachii
C. Branch to the triceps
D. Phrenic nerve
E. Musculocutaneous nerve
D: The phrenic nerve because it innervates the diaphragm.
Which one of the plexes innervates the posterior thigh and most of the leg and foot? A. Cervical B. Brachial C. Lumbar D. Sacral E. None of the above
D: The sacral plexus innervates the posterior thigh and most of the leg and foot.
Miniature endplate potentials are essential for which of the following?
A. Inhibiting the action of lower motor neurons
B. Initiating contraction of muscles
C. Preventing atrophy of muscle fibers
D. A and B
E. All of the above
C: Miniature endplate potentials provide trophic factors to skeletal muscle fibers that are essential to prevent atrophy.
Trophic changes after denervation include which of the following?
A. Muscle atrophy
B. Shiny skin
C. Brittleness of fingernails and toenails
D. A and B
E. All of the above
E: Tropic changes after denervation include muscle atrophy, shiny skin, and brittleness of fingernails and toenails
Rupture of the ulnar nerve, secondary to the fracture of the humerus
What is this type of lesion classified as?
Traumatic severance
Decreased sensation in a stocking/glove distribution
What is this type of lesion classified as?
Polyneuropathy
Loss of sensory, autonomic, and motor function of the right musculocutaneous and femoral nerves and the left sciatic nerve
What is this type of lesion classified as?
Multiple mononeuropathy
Chronic compression of the median nerve resulting in mild demyelination
What is this type of lesion classified as?
Traumatic myelinopathy
Crushing injury of the peroneal nerve
What is this type of lesion classified as?
Traumatic axonopathy
List at least three specific factors that may cause polyneuropathy.
Polyneuropathy may be caused by diabetes, nutritional deficiency secondary to alcoholism, autoimmune diseases, prolonged use of therapeutic drugs, or exposure to environmental toxins.
What sensory changes commonly occur with diabetic polyneuropathy?
Decreased sensation in a stocking/glove distribution, pain, paresthesia, and dysesthesia commonly occur with diabetic polyneuropathy.
What autonomic changes may occur with diabetic polyneuropathy?
Cardiovascular, gastrointestinal, genitourinary, and sweating dysfunctions may occur with diabetic polyneuropathy.
How is botulinum toxin therapeutically used?
Botulinum toxin interferes with the release of acetylcholine (Ach) at the neuromuscular junction and is used to weaken overactive muscles in dystonia and spasticity.
In a recording from a nerve conduction velocity (NCV) study, decreased amplitude of recorded potentials, combined with slowing of NCV, indicates which of the following? A. Myelinopathy B. Myopathy C. Myasthenia gravis D. Upper motor neuron lesion E. Axonopathy
E: Axonopathy reduces both the amplitude and velocity of recorded potentials during a nerve conduction velocity study. Traumatic myelinopathy causes decreased velocity but usually not amplitude of recorded potentials. Myopathy only affects muscle and so amplitude of recorded potentials is decreased but velocity of conduction is normal. Myasthenia gravis damages ACh receptors on the muscle membrane, so conduction velocity is normal but recorded amplitude decreases with repeated muscle contractions. Because NCV studies only test peripheral nerves, NCV studies are normal in UMN lesions.
If NCV studies show that conduction is slowed at a single site in one nerve, yet the NCV is normal throughout the remainder of the nerve and in other nerves, the disorder is characterized as which of the following? A. Traumatic myelinopathy B. Axonopathy C. Severance injury D. Myopathy E. Polyneuropathy
A: Traumatic myelinopathy is limited to a single site on a nerve, so nerve conduction proximal and distal to the site of myelinopathy is normal.
If the NCV is normal along the length of the peripheral nerve, yet the amplitude of the electromyogram (EMG) potential is decreased, the disorder is: A. Myelinopathy B. Myopathy C. Lower motor neuron lesion D. Upper motor neuron lesion E. Axonopathy
B: Axonopathy reduces both the amplitude and velocity of recorded potentials during a nerve conduction velocity study. Traumatic myelinopathy causes decreased velocity but usually not amplitude of recorded potentials. Myopathy only affects muscle and so amplitude of recorded potentials is decreased but velocity of conduction is normal. Myasthenia gravis damages ACh receptors on the muscle membrane, so conduction velocity is normal but recorded amplitude decreases with repeated muscle contractions. Because NCV studies only test peripheral nerves, NCV studies are normal in UMN lesions.
Myasthenia gravis is an autoimmune disease affecting the:
A. Myelin of peripheral nerves
B. ACh receptors at the neuromuscular junction
C. Release of ACh from the presynaptic terminal
D. Storage of calcium in the sarcoplasmic reticulum
E. Alpha motor neurons in the ventral horn of spinal cord
B: Myasthenia gravis is an autoimmune disease that damages ACh receptors on the muscle membrane.
Guillian-Barré syndrome is an autoimmune disease that causes: A. Necrosis of the alpha motor neuron B. Degeneration of the motor endplate C. Spasticity D. Peripheral demyelination E. Degeneration of the C-fiber axons
D: Guillian-Barré syndrome is an autoimmune disease that causes peripheral demyelination. This polyneuropathy has a rapid onset, with progressive paralysis that may require treatment to prevent respiratory failure. The motor system is usually more affected than the sensory system, but deafferentation pain may be severe.
Define Hereditary motor and sensory neuropathy (HMSN; also known as Charcot-Marie-Tooth disease)
Genetic neuropathy that begins with paresis of muscles distal to the knee, with resulting foot drop, a steppage gait, frequently tripping, and muscle atrophy. As the disease slowly progresses, muscle atrophy and paresis affect the hands and the ability to sense heat, cold, and painful stimuli decreases. Neuropathic pain is common.
