Question 1

Which of the following structures in the vestibular apparatus is responsible for the detection of angular acceleration?&#10;A)Statoconia&#10;B)Macula&#10;C)Semicircular canals&#10;D)Saccule

Accepted Answer

The semicircular canals are responsible for detecting angular acceleration, which is changes in the rate of rotational movement of the head. The other structures listed are responsible for detecting other types of movement or changes in position, such as gravity or linear acceleration.

Question 2

Fine motor movement of the index finger can be elicited by stimulation of which of the following brain areas?&#10;A)Primary motor cortex&#10;B)Lateral cerebellar hemisphere&#10;C)Premotor cortex&#10;D)Supplemental motor area

Accepted Answer

The primary motor cortex is responsible for the execution of voluntary motor movements, including fine motor movements of the fingers.

Question 3

Decerebrate rigidity caused by simultaneous contraction of both the agonist and antagonist muscles in a limb can be alleviated by which of the following maneuvers?&#10;A)Turning the head sharply toward the limb&#10;B)Bending the head forward&#10;C)Stimulating the pontine reticular formation by lightly stroking the palms of the hand&#10;D)Cutting the dorsal roots associated with the affected limb

Accepted Answer

Cutting the dorsal roots associated with the affected limb interrupts the sensory input that contributes to the reflex arc causing the rigidity, thereby alleviating the condition.

Question 4

The rubrospinal tract originates from which area of the brain?&#10;A)Magnocellular area of the red nucleus&#10;B)Superior olivary nucleus&#10;C)Pontine reticular formation&#10;D)Nucleus raphe magnus

Accepted Answer

The rubrospinal tract originates from the magnocellular area of the red nucleus in the midbrain.

Question 5

The maintenance of static equilibrium with the head in a near vertical position is achieved by which of the following?&#10;A)Cristae ampullaris&#10;B)Cupula&#10;C)Maculae&#10;D)Organ of Corti

Accepted Answer

Maculae within the utricle and saccule of the inner ear sense changes in linear acceleration and head position, maintaining static equilibrium when the head is in a near vertical position. Cristae ampullaris and cupula are involved in detecting changes in rotational acceleration and head movement. The Organ of Corti is responsible for detecting sound waves.

Question 6

Which of the following brain regions contributes fibers to the corticospinal tract?&#10;A)Somatic sensory cortex&#10;B)Supplemental motor area&#10;C)Primary motor cortex&#10;D)All of the above

Accepted Answer

The corticospinal tract is composed of fibers originating from several areas of the brain, including the somatic sensory cortex, supplemental motor area, and primary motor cortex, thus all the options listed contribute fibers to it.

Question 7

The stretch reflex is used clinically to assess which of the following?&#10;A)Integrity of the corticospinal tract&#10;B)Function of the vestibulo-ocular reflex&#10;C)Level of activity of the gamma motor system&#10;D)Function of the vestibular system

Accepted Answer

The stretch reflex is a monosynaptic reflex arc that involves the activation of muscle spindles and the contraction of muscle fibers. The gamma motor system, which regulates the sensitivity of muscle spindles, plays a crucial role in the stretch reflex. Therefore, the stretch reflex can be used clinically to assess the level of activity of the gamma motor system. A decrease or absence of the stretch reflex suggests a dysfunction in the gamma motor system.

Question 8

Linear acceleration is most likely to be transduced in which of the following structures?&#10;A)Cristae ampullaris&#10;B)Cupula&#10;C)Maculae&#10;D)Organ of Corti

Accepted Answer

Maculae are sensory structures located in the utricle and saccule of the inner ear, which are responsible for detecting linear acceleration and changes in head position relative to gravity. They contain hair cells that transduce mechanical stimuli into neural signals sent to the brainstem. Cristae ampullaris (A) and cupula (B) are sensory structures located in the semicircular canals, which are responsible for detecting rotational acceleration. The organ of Corti (D) is responsible for transducing sound waves into neural signals.

Question 9

Which of the following is paired correctly?&#10;A)Gamma motor neuron and extrafusal muscle fiber&#10;B)Alpha motor neuron and intrafusal muscle fiber&#10;C)Betz cells and corticospinal tract&#10;D)Utricle and angular acceleration detection

Accepted Answer

Betz cells are large pyramidal neurons located in the primary motor cortex (Brodmann area 4) and are directly involved in the generation of voluntary motor movements. They are a major component of the corticospinal tract, which is responsible for carrying movement-related information from the brain to the spinal cord, thus facilitating the control of motor functions. The other options incorrectly pair neural components with their functions or associated structures.

Question 10

In the right horizontal semicircular canal, rapid rotation of the head in the clockwise direction will cause the endolymph to move in which relative direction?&#10;A)Clockwise&#10;B)Counterclockwise&#10;C)Upward&#10;D)Downward

Accepted Answer

When the head is rotated clockwise, the inertia of the endolymph causes it to move in the opposite direction, which is counterclockwise, relative to the canal.

Question 11

&#10;The figure above represents the response of a hair cell in the crista ampullaris of the semicircular canal to stimulation by rotation in a human subject. With the subject's eyes closed, the subjective sensation of rotation will be absent at which point(s)?&#10;A)A&#10;B)B&#10;C)C&#10;D)A and C

Accepted Answer

The answer of  &#10;The figure above represents the response...

Question 12

The phenomenon of decerebrate rigidity can be explained, at least in part, by which of the following?&#10;A)Stimulation of gamma motor neurons&#10;B)Loss of cerebellar inputs to the red nucleus&#10;C)Overactivity of medullary reticular nuclei involved in motor control

Accepted Answer

The answer of The phenomenon of decerebrate rigidity can be...

Deck 56: Cortical and Brain Stem Control of Motor Function