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Hi, Could someone please explain and answer the follow questions, that i got wrong?


The main

function of the basal ganglia appears to be

Select one:

a. Planning motor programs

b. Execution of motor programs

c. Selection of desired motor programs and suppression of undesired ones

d. Modulating the function of the cerebellum

e. Specifying the sequence and extent of motor programs


Which of the following is CORRECT?

Select one:

a. By increasing the intensity of electrical stimulation in the mesencephalic locomotor region, one can change an animal's pace from slow walking to gallop.

b. The neurones involved in the flexion and cross-extension reflex are located primarily in the mesencephalon.

c. Walking in a straight line requires a constant input from the cerebral cortex, so that the decisions to move one foot in front of the other are communicated to the spinal motorneurones.

d. Walking in a straight line requires a constant input from the cerebellun, so that the decisions to move one foot in front of the other are communicated to the spinal motorneurones.

e. The cerebellum is not involved in postural adjustments, but plays a crucial role in locomotion.


The medial group of descending motor tracts

Select one:

a. directly connect the cortex to the spinal cord

b. controls fine movements of the extremities

c. is mostly concerned with postural control

d. connects a number of brainstem nuclei with the spinal cord

e. C and D above


Because of the lever action of the bones of the arm, when a weight is held in the hand, the flexor muscles of the upper arm

Select one:

a. can move the weight even though they exert less force than the weight provides.

b. shorten more rapidly than the speed at which the weight is moved.

c. only need to contract if the weight actually has to be moved.

d. need to exert progressively less force as the elbow joint becomes more flexed.

e. need to exert a considerably greater force than that provided by the weight.


The flocculonodular lobe of the cerebellum (vestibulocerebellum) would be most heavily involved in which type of movement:

Select one:

a. learning to play tennis

b. lying supine

c. initiating a walking movement

d. walking on a tight-rope

e. playing computer games


Which of the following is CORRECT?

Select one:

a. By increasing the intensity of electrical stimulation in the

mesencephalic locomotor region, one can change an animal's pace from slow walking to gallop.

b. The neurones involved in the flexion and cross-extension reflex are located primarily in the mesencephalon.

c. Walking in a straight line requires a constant input from the cerebral cortex, so that the decisions to move one foot in front of the other are communicated to the spinal motorneurones.

d. Walking in a straight line requires a constant input from the cerebellun, so that the decisions to move one foot in front of the other are communicated to the spinal motorneurones.

e. The cerebellum is not involved in postural adjustments, but plays a crucial role in locomotion.


Some skeletal muscles contract more quickly than others because

Select one:

a. they depend entirely on glycolytic metabolism as a source of energy.

b. they tend to have a lower rate of release of calcium ions during the contraction cycle.

c. they are composed exclusively of small fatigueresistant muscle fibres.

d. the myosin ATPase contained by them has a higher intrinsic activity.

e. they contain more muscle fibres.


Parkinson's disease results from

Select one:

a. A dopamine deficiency that results in excessive inhibition of the thalamus

b. Reduced serotonin supply to the substantia nigra, pars compacta

c. A dopamine deficiency that results in excessive excitation of the thalamus

d. A lesion of the subthalamic nucleus that results in excessive excitation of the cerebral cortex

e. Underactivity in the indirect pathway that results in hyperkinesis


The increase in muscle mass following strength training

Select one:

a. only occurs in males because testosterone is necessary for muscle growth.

b. is due mostly to a massive proliferation of connective tissue in the exercising muscles.

c. results from an increase in the size of individual muscle fibres and not from an increase in the number of muscle fibres.

d. results from an oversupply of lactic acid which stimulates the production of more muscle fibres.

e. involves a conversion of slow oxidative (Type I) fibres to fast glycolytic (Type IIB) fibres.


Which of the following statements is CORRECT?

Select one:

a. The function of the supplementary motor area is to serve as a "back up" mechanism in case of lesions of the primary motor area.

b. The dorsal and ventral premotor areas are important in the planning of movements that are prompted by external sensory cues; for example, if the movement has to be guided by visual information.

c. The supplementary motor area is primarily involved in the control of vocalisations.

d. Self-initiated acts are planned entirely by cells located in the primary motor area (M1), without involvement of the supplementary of premotor areas.

e. The firing rate of neurons in M1 is proportional to the change in angle required at the relevant joint


In the crossbridge cycle:

Select one:

a. ATP is required to remove the inhibitory influence of tropomyosin and troponin.

b. the binding of Ca2+ to myosin is required to initiate crossbridge movement in the "power stroke".

c. the release of ADP and Pi from myosin is associated with the "power stroke" of the cross-bridge.

d. ATP is split immediately after myosin has bound to actin.

e. each crossbridge is only able to undergo one cycle of attachment to actin.


Acetylcholine causes a depolarisation of the end-plate region of skeletal muscle because it

Select one:

a. Is positively charged and enters the cell in the same way as does Na+ during an action potential.

b. Causes an increase in conductance for Na+ ions only.

c. Causes an increase in conductance for small cations.

d. Causes an increase in conductance for both cations and anions.

e. Triggers a voltage dependent conductance change just as occurs during generation of an action potential.


Which ONE of the following statements concerning muscle spindles is CORRECT?

Select one:

a. They are arranged in series with the ordinary muscle fibres.

b. Afferent volleys in 1A fibres inhibit the homonymous motoneurones.

c. They are most commonly located at the muscle-tendon junction.

d. Impulses in the spiral sensory ending are set up by shortening of the ending leading to compression of the spirals.

e. The polar, striated portions of the intrafusal fibres are contractile.


Parkinson's disease is characterised by reduced movement initiation, slow movements, rigidity and resting tremor. This is caused by

Select one:

a. increased serotonin production in the substantia nigra, which is part of the cerebellum

b. decreased dopamine production in the substantia nigra, which is part of the cerebellum

c. increased dopamine production in the substantia nigra, which is part of the basal ganglia

d. decreased dopamine production in the substantia nigra, which is part of the basal ganglia

e. decreased serotonin production in the substantia nigra, which is part of the basal ganglia


The spinocerebellum is most heavily involved in which type of movement:

Select one:

a. starting the sequence of throwing a ball

b. learning to ski

c. climbing a ladder

d. playing action computer games

e. lying supine


Which of the following is CORRECT?

Select one:

a. The cerebral cortex has no influence in locomotion.

b. The cerebral cortex has a random effect on locomotion.

c. Decisions about changes in a person's posture require the participation of the cerebral cortex. However, many automatic responses can be coordinated at the levels of brainstem and spinal cord.

d. When a person changes the direction of locomotion in order to avoid an obstacle, this can be done entirely by using spinal circuits.

e. A cat in which the cerebral cortex has been completely destroyed cannot perform any kind of postural adjustment.


The phasic stretch reflex or tendon jerk in response to a tendon tap

Select one:

a. Is the result of the excitation of tendon organs lying in the tendon being tapped.

b. Is triggered by the brief shortening applied to the muscle as a result of the tendon tap.

c. Is initiated by the command centre in the brain.

d. Is the result of excitation of the primary endings of muscle spindles by the brief stretch applied to the tendon.

e. Is a purely muscle mechanical response and does not require an intact nerve supply.


Which of the following is INCORRECT? In a motoneurone,

Select one:

a. the action potential is generated first in the axon hillock region.

b. the cell body is unable to conduct all-or-nothing action potentials.

c. synaptic potentials may be generated out in the dendrites.

d. once generated, an action potential can travel both forwards into the axon and backwards into the cell body.

e. synaptic potentials are able to sum with one another.


Motor neurones:

Select one:

a. Are just like muscle fibres in that each receives terminals of a single afferent (sensory) nerve fibre.

b. If small, are more responsive to a set level of synaptic activity than if they are larger.

c. If large, are more responsive to a set level of synaptic activity than if they are smaller.

d. Are unable to fire repetitively.

e. All conduct APs at about the same velocity.


The sense of muscle tension

Select one:

a. Is provided by signals from tendon organs

b. Is not present if a muscle is fully fatigued.

c. Is provided by the secondary endings of muscle spindles.

d. Is only felt when tension levels are high enough to risk damage to the muscle.

e. Represents the afferent limb of the stretch reflex.


Following damage to axons in the descending lateral corticospinal tract, motor reflexes

Select one:

a. are initially lost, but return at an exaggerated level due to the loss of descending inhibition

b. are initially lost, but return at a reduced level due to increased descending inhibition

c. are initially unaffected, but eventually lost due to the death of lower motor neurons

d. are immediately lost and do not return due to the the death of lower motor neurons

e. are unaffected


During isotonic contraction of a muscle

Select one:

a. the muscle generates progressively more force as it shortens.

b. the muscle generates less power than during a maximal isometric contraction.

c. the thick and thin filaments shorten pulling the Z-lines closer together.

d. the muscle will shorten with a slower velocity if the load is heavier.

e. both the force and length of the muscle remain constant.


What is sarcoplasmic reticulum (SR)?

Select one:

a. Excitable cell membrane that encloses the muscle fiber.

b. Extensive intracellular sac containing calcium ions.

c. System of tubules that bring the action potential deep inside the muscle fiber.

d. Voltage-sensitive channels.

e. Site of muscle protein synthesis.


The surface area of primary motor cortex devoted to a myotatic unit is most closely related to:

Select one:

a. the surface area of the muscles

b. the degree of fine control of the muscles

c. the number of muscles associated with the joint

d. the range of force that the muscles can generate

e. the volume of the muscles


Because of the lever action of the bones of the arm, when a weight is held in the hand, the flexor muscles of the upper arm

Select one:

a. can move the weight even though they exert less force than the weight provides.

b. shorten more rapidly than the speed at which the weight is moved.

c. only need to contract if the weight actually has to be moved.

d. need to exert progressively less force as the elbow joint becomes more flexed.

e. need to exert a considerably greater force than that provided by the weight.

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