Please add anything you think is important Let s focus more on the key terms Any term that YOU think she didn t go over are uncertain about highlight in a different color i e Orange Maybe she did and you missed it basically don t delete anything off the outline we don t want to miss anything PSB2000 EXAM III STUDY GUIDE Movement and Movement Disorders 1 What is the neuromuscular junction What neurotransmitter is used What is the difference in innervating muscles used for fine movements as opposed those for more forceful movement Neuromuscular junction a synapse where a motor neuron axon meets with a muscle fiber Neurotransmitter used Acetylcholine excites muscle to contract Muscles used for fine movement have neuron motor axons which innervate only a few muscle fibers ex in the eye while muscles used in forceful movement have axons which innervate many muscle fibers ex bicep 2 What are muscle spindles and golgi tendon organs Activity in 1 results in contraction of the muscle activity in the other results in relaxation of the muscle Which is which What are the reflexes I m talking about Muscle spindles are a type of proprioceptor parallel to a muscle that responds to a stretch When the muscle spindle is stretched its sensory neuron sends a message to a motor neuron in spinal cord which sends a message back to muscles surrounding the spindle causing a contraction Ex stretch reflex knee jerk reflex Golgi tendon organs are proprioceptors located in tendons at opposite ends of muscles which act as a brake against vigorous contraction Golgi tendon organs detect tension during a muscle contractions send impulses to spinal cord where they excite interneurons that inhibit the motor neurons causing relaxation Ex Reaching for a can you think is full but is actually empty Golgi tendon helps tweak the force so does the Golgi tendon organ have a particular reflex like the muscle spindles It s called the Golgi tendon reflex 3 What is the flexor reflex The flexor reflex is the reflex responsible for withdrawing from painful stimuli It is Initiated by cutaneous receptors Tonic inhibition only something strong painful can activate it Full limb involvement includes primary afferent bifurcate which includes interneurons Changes based on location of stimulation Crossed effect can affect opposite sides of body 4 Know understand the 3 infant reflexes we discussed Other than infancy when else would you expect to see these Grasp reflex if you put something in an infant s hand they will grasp it Babinski reflex if you stroke the bottom of an infant s foot it will extend its big toe and fan the others Also happens in drunk people and people with brain injuries Rooting reflex if you stroke an infant s cheek they will turn towards that cheek and start sucking You can expect to see these reflexes if the cerebral cortex is damaged or if alcohol carbon dioxide or other chemicals decreases activity in the cerebral cortex 5 Compare contrast central pattern generators and motor programs in terms of where they are in the nervous system and what they are for Central pattern generators are neural mechanisms in the spinal cord that generate rhythmic patterns of motor output Ex bird wing flapping fin movements in fish and wet dog shake Motor programs are automatic fixed sequences of movement which can be learned or programmed and are located in the spinal cord brainstem and cerebellum Ex yawning with stretch smiling frowning 6 Where is primary motor cortex What is the homunculus and what does it tell us What feeds into primary motor cortex and where does it project former part of this question it is important to understand that the final command is generated in primary motor cortex but it needs lots of info from many places to make that command properly latter part of this question think corticospinal tract and lower motor neurons and ventral horn of spinal cord Why are there important connections from primary motor cortex to the brainstem The primary motor cortex is located in the posterior of the frontal lobe and contains upper motor neurons The homunculus is a depiction of how the primary motor cortex is related to the body and tells us which cells in the primary motor cortex control which parts of the body The supplementary motor cortex prefrontal motor cortex parietal temporal and frontal association cortices and the primary somatosensory cortex all feed into the primary motor cortex 7 Where are premotor cortex and supplementary motor cortex and what is each important for Both are located in the frontal lobe anterior to the primary motor cortex The premotor cortex is active right before a movement and is important because it receives information about the target to which the body is directing its movement as well as information about the body s current position and posture The supplementary motor cortex is important for planning and organizing a rapid sequence of movements Also important for inhibiting a habitual action when you need to do something else 8 What is the role of the cerebellum in movement The cerebellum is important for motor control like coordination balance posture control learned motor response and skills rapid ballistic movements that require aim and timing cognition and attention and timing sensory and movement Think of the cerebellum as an internal clock in charge of timing the sequence and duration of movements 9 What is the role of the basal ganglia in movement The basal ganglia includes the caudate nucleus the putamen and the globus pallidus Inputs comes to the caudate nucleus and putamen from cerebral cortex and output from c n and putamen goes to globus pallidus The globus pallidus constantly inhibits the thalamus through GABA Input from c n and putamen tells the globus pallidus which movements to stop inhibiting The thalamus relays info to the cerebral cortex Basically the basal ganglia selects a movement by ceasing to inhibit it 10 For Parkinson s disease and Huntington s disease know what part of the basal ganglia is involved and what the symptoms are and how these relate to the general function of the basal ganglia The caudate nucleus is involved In Parkinson s dopamine producing cells in the substantia nigra are destroyed This leads to less excitation of c n and putamen and less inhibition of the globus pallidus leading to too much inhibition of the thalamus and too much inhibition of cortex In Huntington s the caudate nucleus and putamen degenerate which leads to not enough
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