Question 1

Which of the following best describes the function of peripheral motor endings in the peripheral nervous system (PNS)?

Accepted Answer

They activate effectors by releasing neurotransmitters.

Question 2

At the neuromuscular junction, which neurotransmitter is released to stimulate skeletal muscle contraction?

Accepted Answer

Acetylcholine

Question 3

Which of the following statements about the innervation of visceral muscle and glands is correct?

Accepted Answer

Autonomic motor endings form synapses en passant with effector cells via varicosities.

Question 4

Why are visceral motor responses generally slower than somatic motor responses?

Accepted Answer

Acetylcholine and norepinephrine act indirectly via second messengers.

Question 5

Which structure releases neurotransmitters into a wide synaptic cleft (diffuse junction) in smooth muscle?

Accepted Answer

Varicosities

Question 6

A patient presents with an abnormal plantar reflex in which the great toe dorsiflexes and the smaller toes fan laterally. What is this sign called, and what does it indicate in an adult?

Accepted Answer

Babinski sign; indicates damage to the primary motor cortex or corticospinal tract

Question 7

Which of the following is NOT a component of a reflex arc?

Accepted Answer

Cerebellum

Question 8

Which type of reflex activates skeletal muscle?

Accepted Answer

Somatic reflex

Question 9

During the stretch reflex, what is the response of the muscle spindle and its antagonist muscle?

Accepted Answer

The stretched muscle contracts and the antagonist is inhibited.

Question 10

Which of the following best describes the function of central pattern generators (CPGs) in the segmental level of motor control?

Accepted Answer

They generate rhythmic patterns of movement such as locomotion.

Question 11

A patient has an absent abdominal reflex. Which of the following is the most likely explanation?

Accepted Answer

The patient has a lesion in the corticospinal tract.

Question 12

Which of the following equations best represents the relationship between the number of synapses per neuron ($$n) $$and the speed of central processing ($$v) as $$people age, assuming all other factors are constant?

Accepted Answer

$$v \propto n$$

Question 13

Which of the following is a correct sequence for the five basic components of a reflex arc?

Accepted Answer

Receptor → Sensory neuron → Integration center → Motor neuron → Effector

Question 14

Which level of the motor control hierarchy is responsible for unconscious planning and coordination of movement with posture?

Accepted Answer

Precommand level

Question 15

Which of the following best explains why the Babinski sign is normal in infants but abnormal in adults?

Accepted Answer

Infants have incomplete myelination of their nervous system.

Question 16

Which neurotransmitters are released by varicosities in autonomic nerve fibers innervating smooth muscle?

Accepted Answer

Acetylcholine and norepinephrine

Question 17

A person steps on a sharp object and immediately withdraws their foot. Which type of reflex is this, and which muscles are activated?

Accepted Answer

Somatic reflex; flexor muscles are activated

Question 18

Which of the following best describes the role of the cerebellum in the precommand level of motor control?

Accepted Answer

It fine-tunes motor activity and coordinates movement via the thalamus.

Question 19

Which of the following is a real-life example of a learned (acquired) reflex?

Accepted Answer

Diving reflex in experienced swimmers

Question 20

If the number of synapses per neuron decreases with age, what is the most likely effect on muscle tone and reflexes in the elderly?

Accepted Answer

Muscle tone decreases and reflexes become slower.

Peripheral Motor Endings and Innervation of Muscle and Glands

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