anatomy exam part 4 Flashcards
Describe the roles of premotor cortex and primary cortex in movement
The premotor cortex appears to be involved in the selection of appropriate motor plans for voluntary movements, whereas the primary motor cortex is involved in the execution of these voluntary movements. Premotor cortexneurons signal the preparation for movement.
Describe the function of upper motor neuron, lower motor neuron, alpha and gamma motor neurons
Efferent motor commands from the cerebral cortex are contralateral or “crossed,” meaning that the left cortex controls the muscles on the right side of the body (and vice versa), whereas the Brainstem influences ipsilateral (same side) motor activity.
Describe the function of upper motor neuron, lower motor neuron, alpha and gamma motor neurons
Lower motor neuron: in ventral horn of spinal cord
Lower Motor Neurons
• SAME DAVE
SAME, sensory afferent, motor efferent
DAVE, dorsal afferent, ventral efferent
- Describe the function of muscle spindle and Golgi
Receptors that allow us to sense our position and posture are called proprioceptors.
- Slow adaptation.
- Weight discrimination.
- Three types: muscle spindles, tendon organs and joint kinesthetic receptors.
Describe the function of muscle spindle and Golgi tendons
tendon organs
- tendon organs – proprioceptors in a tendon near its junction with a muscle
* Golgi tendon organ - 1mm long, nerve fibers entwined in collagen fibers of the tendon - tendon reflex – in response to excessive tension on the tendon
- inhibits muscle from contracting strongly
- moderates muscle contraction before it tears a tendon or pulls it loose from the muscle or bone
Describe the function of upper motor neuron, lower motor neuron, alpha and gamma motor neurons
Upper motor neurons → lower motor neurons → skeletal muscles.
Neural circuits involving basal ganglia and cerebellum regulate activity of the upper motor neurons
- Describe corticospinal and corticobulbar pathways
- Direct motor pathway- originates in the cerebral cortex.
- Corticospinal pathway: to the limbs and trunk.
- Corticobulbar pathway: to the head.
- Indirect motor pathway- originates in the brain stem.
Describe three peduncles and their functions in cerebellum; Describe the function of cerebellum in movement control
superior peduncles – connected to the midbrain carries cerebellar output
middle peduncles – connected to the pons
most input from the rest of the brain enters by way of middle peduncle
inferior peduncles – connected to medulla oblongata
most spinal input enters the cerebellum through inferior peduncle
consist of thick bundles of nerve fibers that carry signals to and from the cerebellum
4
SEMIA:
Superior peduncle
Efferent (output)
Middle and Inferior peduncles
Afferent (input)
When you decide to swing a bat, the decision to make this movement originates in
A. prefrontalcortex.
B. the basal ganglia.
C. the cerebellum.
D. primary motor cortex.
In producing movement, the last cortical area to be activated is the
premotor area.
association cortex.
supplementary motor cortex.
primary motor cortex.
premotor area.
association cortex.
supplementary motor cortex.
primary motor cortex.
The actual execution of a movement is triggered by activity in the
primarymotorcortex.
supplementary motor cortex.
premotor cortex.
prefrontal cortex.
Which brain areas contribute to the smoothness of movement?
A. cerebellum and premotor cortex
B. supplementary motor cortex and basal ganglia
C. prefrontal cortex and premotor cortex
D. cerebellum and basal ganglia
A. cerebellum and premotor cortex
B. supplementary motor cortex and basal ganglia
C. prefrontal cortex and premotor cortex
D. cerebellum and basal ganglia
The spinal motor neurons directly responsible for contracting muscles are known as
A. alphamotorneurons.
B.beta motor neurons.
C.motor units.
D. fast-twitch motor neurons.
A. alphamotorneurons.
B.beta motor neurons.
C.motor units.
D. fast-twitch motor neurons.
The “normal” contractile fibers of the muscle are also called the
A. extrafusalfibers.
B.intrafusal fibers.
C.muscle spindle fibers
D. gamma fibers
A. extrafusalfibers.
B.intrafusal fibers.
C.muscle spindle fibers
D. gamma fibers
Alpha motoneurons innervate
A.nuclear chain fibers.
B. nuclear bag fibers.
C. extrafusal fibers.
D. intrafusalfibers.
A. nuclear chain fibers.
B.nuclear bag fibers.
C.extrafusal fibers.
D. intrafusalfibers.
