Q: Which equation best represents the relationship between the number of muscle fibers ($$N_{mf}) $$and the number of motor units ($$N_{mu}) in a $$muscle?

$$N_{mf} = N_{mu} \times N_{fpu}$$, where $$N_{fpu} is $$the number of fibers per unit

Question 1

Which neurotransmitter is released at the neuromuscular junction to initiate muscle contraction?

Accepted Answer

Acetylcholine

Question 2

A patient presents with muscle weakness, ptosis, and difficulty swallowing. Blood tests reveal antibodies against acetylcholine receptors. What is the most likely diagnosis?

Accepted Answer

Myasthenia gravis

Question 3

Which of the following is a common cause of mononeuropathy resulting in pain and numbness in the thumb and first two fingers?

Accepted Answer

Compression of the median nerve at the wrist (Carpal Tunnel Syndrome)

Question 4

Damage to which part of the motor system is responsible for spastic cerebral palsy?

Accepted Answer

Motor cortex and pyramidal tracts

Question 5

Which of the following best describes the pathophysiology of muscular dystrophy?

Accepted Answer

Progressive deterioration of skeletal muscle due to genetic defects causing cell hypertrophy, atrophy, and necrosis

Question 6

A patient with ALS is most likely to show which of the following clinical features early in the disease?

Accepted Answer

Muscle cramps involving the distal legs

Question 7

Which equation best represents the relationship between the number of muscle fibers ($$N_{mf}) $$and the number of motor units ($$N_{mu}) in a $$muscle?

Accepted Answer

$$N_{mf} = N_{mu} 	imes N_{fpu}$$, where $$N_{fpu} is $$the number of fibers per unit

Question 8

Which of the following is a primary function of the cerebellum?

Accepted Answer

Coordination of motor movement and balance

Question 9

A patient with Parkinson's disease is most likely to have a deficiency of which neurotransmitter in the basal ganglia?

Accepted Answer

Dopamine

Question 10

Which of the following is a characteristic feature of upper motor neuron lesions?

Accepted Answer

Hypertonia (increased muscle tone)

Question 11

A patient presents with symmetric weakness and tingling in the feet that progresses upward. He recently had a flu-like illness. Which condition is most likely?

Accepted Answer

Guillain-Barré syndrome (acute polyneuropathy)

Question 12

Which of the following best explains why infants are at higher risk for botulism from honey?

Accepted Answer

Infants have immature GI tracts that allow botulinum toxin absorption

Question 13

Which of the following spinal cord syndromes is characterized by flaccid bowel and bladder and altered sexual function?

Accepted Answer

Conus medullaris syndrome

Question 14

Which of the following is the most urgent complication of spinal cord injury affecting the cervical region?

Accepted Answer

Respiratory impairment and loss of airway control

Question 15

Which of the following is a distinguishing feature of multiple sclerosis (MS) compared to ALS?

Accepted Answer

MS is characterized by demyelination of CNS axons and relapsing-remitting episodes

Question 16

Which pathway in the basal ganglia is primarily responsible for smooth movement control and is affected in Parkinson's disease?

Accepted Answer

Dopamine pathway

Question 17

A patient with a ruptured intervertebral disk is most likely to experience which of the following symptoms?

Accepted Answer

Paresthesias and numbness in the leg and foot

Question 18

Which of the following drugs is used to block the effects of acetylcholine in the treatment of Parkinson's disease?

Accepted Answer

Anticholinergic drugs

Question 19

Which of the following best describes the clinical presentation of polyneuropathy?

Accepted Answer

Symmetric sensory, motor, or mixed deficits beginning in the distal extremities

Question 20

Which of the following is the correct sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Acetylcholine is released from the axon terminal, binds to receptors on the muscle end plate, and causes contraction

15 patho

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