\\\\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 GUIDEMovement and Movement Disorders1. 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 reflexGolgi 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 itBabinski 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 suckingYou 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 shakeMotor 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
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