Question 1

A polysynaptic reflex has at least ________ in the reflex pathway.

Accepted Answer

A polysynaptic reflex involves at least one interneuron between the sensory and motor neurons, resulting in a minimum of two synapses and three neurons (sensory neuron, interneuron, and motor neuron) in the reflex pathway.

Question 2

The reflex that complements a withdrawal reflex by making compensatory adjustments on the opposite side of the body receiving the stimulus is the

Accepted Answer

The crossed extensor reflex complements a withdrawal reflex by making compensatory adjustments on the opposite side of the body receiving the stimulus. For example, if you step on a sharp object with your right foot, the withdrawal reflex would cause you to quickly pull your right foot away from the object. At the same time, the crossed extensor reflex would cause your left leg to extend and support your body weight, helping you to maintain balance and not fall over. The other options (stretch reflex, tendon reflex, flexor reflex, reciprocal reflex) do not involve compensatory adjustments on the opposite side of the body and do not complement a withdrawal reflex.

Question 3

Motor neurons are sometimes inhibited by

Accepted Answer

Golgi tendon organs are sensory receptors located in tendons that detect changes in muscle tension. When activated, they can inhibit the activity of motor neurons, preventing excessive muscle contraction or damage. Muscle spindle organs and joint receptors, on the other hand, are involved in sensory feedback to adjust muscle tone and maintain posture, but they do not directly inhibit motor neuron activity.

Question 4

Which class of movement can be considered a combination of the other two?

Accepted Answer

Rhythmic movements can be considered a combination of reflex and voluntary movements. While they are initiated by a reflex arc, the pattern of movement itself is voluntarily modulated and modified in response to sensory feedback. Examples of rhythmic movements include walking, running, and swimming.

Question 5

The reflex that prevents a muscle from exerting too much tension is the

Accepted Answer

The answer of The reflex that prevents a muscle from...

Question 6

It is the middle of winter and you walk over an icy patch and lose your balance.As you begin to fall, you react by extending your arms to catch yourself.In this instance, what type of reflex is occurring?

Accepted Answer

The crossed extensor reflex is a reflex that occurs when one limb is extended and the opposite limb is flexed. This reflex helps to maintain balance and prevent the body from falling. In the given scenario, the person is falling and extends their arms to catch themselves. This is an example of the crossed extensor reflex.

Question 7

Identify the False statement.

Accepted Answer

Not all reflexes require input from the brain. Some reflexes, such as the knee-jerk reflex, are mediated at the level of the spinal cord and do not require input from higher brain centers.

Question 8

Which is NOT True regarding autonomic reflexes?

Accepted Answer

Autonomic reflexes are typically polysynaptic, with multiple synapses in the central nervous system.

Question 9

Match the type of reflex to its description.
-integrated in the brain

Accepted Answer

Cranial reflexes are integrated in the brain, specifically in the cranial nerves.

Answer: C and G 
 Spinal reflexes are integrated in the spinal cord, and polysynaptic reflexes involve multiple interneurons in the reflex arc.

All other answer choices are descriptions that could apply to multiple types of reflexes.

Question 10

Most reflex movements are integrated by

Accepted Answer

Reflex movements are rapid, automatic responses to a specific stimuli that are integrated by the spinal cord without conscious thought or decision-making from the brain. While the brain can modulate some reflexes, the initial processing and response occurs at the spinal cord level.

Question 11

The structure whose abnormal function is associated with Parkinson's disease is the

Accepted Answer

The basal ganglia is the structure whose abnormal function is associated with Parkinson's disease. Specifically, loss of dopaminergic neurons in the substantia nigra, which provide input to the basal ganglia, is a hallmark of Parkinson's disease. This results in a decrease in dopamine levels in the basal ganglia, leading to the characteristic motor symptoms of the disease.

Question 12

Which reflex is NOT controlled by the brain stem?

Accepted Answer

Urination reflex is not solely controlled by the brain stem, but also involves the spinal cord and the bladder.

Question 13

The flexion reflex

Accepted Answer

The flexion reflex moves a limb away from a painful stimulus, providing protection to the body.

Question 14

The sensory fibers of the muscle spindle organs synapse onto

Accepted Answer

The sensory fibers of the muscle spindle organs synapse onto alpha motor neurons, which innervate the extrafusal muscle fibers causing them to contract. This is how muscle spindle organs are involved in reflexes such as the stretch reflex.

Question 15

Interneurons of the corticospinal tract synapse onto

Accepted Answer

The corticospinal tract is responsible for controlling voluntary movements of the body. The interneurons of this tract synapse onto somatic or skeletal muscle efferents, which are responsible for movements of the arms, legs, and trunk. They do not synapse onto visceral efferents, which control smooth and cardiac muscles, or interneurons of central pattern generators, which are responsible for rhythmic movements like breathing and walking.

Question 16

The effector in a reflex is the

Accepted Answer

The effector in a reflex arc is the muscle or gland that responds to the efferent signals coming from the central nervous system, executing the response to the stimulus.

Question 17

Match the type of reflex to its description.
-several neurons involved in a pathway; can be complex

Accepted Answer

A reflex with several neurons involved in a pathway that can be complex is a polysynaptic reflex.

Question 18

Most reflexes are regulated by

Accepted Answer

The answer of Most reflexes are regulated by
...

Question 19

Spinal interneurons prevent muscle antagonists from interfering with an intended movement by

Accepted Answer

The process of reciprocal inhibition involves the inhibition of motor neurons that control the antagonist muscles to the intended movement, allowing for the smooth execution of the movement without interference from opposing muscles.

Question 20

The "normal" contractile fibers of the muscle are also called the

Accepted Answer

Extrafusal fibers are the typical contractile muscle fibers that are responsible for generating force and movement. Intrafusal fibers are specialized muscle fibers found within muscle spindles and are involved in muscle stretch reflexes. Muscle spindle fibers are another term for intrafusal fibers.

Quiz 13: Integrative Physiology I: Control of Body Movement