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Bio Psych Exam 3 Pt2
Ch 8: Movement
| Question | Answer |
|---|---|
| How many messages can be sent to muscles? Which? | One; to contract |
| What are the types of muscles? | 1. Smooth Muscles 2. Skeletal/Striated Muscles 3. Cardiac Muscles |
| How do muscle fibers work? | Muscles are composed of many individual fibers, each receiving input from only 1 axon, while axons can innervate many fibers (the more fibers are innervated, the less specific the movement) |
| What is Neuromuscular Junction? | The synapse between a motor neuron axon & a muscle fiber; where chemicals (ACh) are released to cause contractions |
| What causes a muscle to contract? | A release of ACh into the neuromuscular junction |
| How do muscles relax? | There is no message to relax, just the absence of a message to contract |
| What are Antagonistic Muscles? | Opposing sets of muscles that are required to move a leg or arm back and forth (because there is no complexity within messages to a single muscle); movement formed through alternating contraction of antagonistic muscles; Flexor & Extensor |
| What is a Flexor? | A type of Antagonistic Muscle (works in opposition of extensors); flexes or raises an appendage |
| What is an Extensor? | A type of Antagonistic Muscle (works in opposition of flexors); extends or straightens an appendage |
| What is Myasthenia Gravis? | An Autoimmune Disease; immune system forms antibodies that attack the ACh receptors at the neuromuscular junction; causes progressive weakness & rapid fatigue of the skeletal muscles (eventual paralysis) |
| What are Striated Muscles? | AKA Skeletal Muscles; involve conscious control; control movement of the body in relation to the environment; two types (fast-twich & slow-twich) |
| What are Smooth Muscles? | Not much conscious control; for things like organs |
| What are Cardiac Muscles? | Intermediate; for the heart |
| What does Fast-Twitch refer to? | A type of Skeletal/Striated muscle fiber; fast contractions; fatigue raipidly; anaerobic (meaning reactions do not require O2); used for quick, powerful movements |
| What does Slow-Twitch refer to? | A type of Skeletal/Striated muscle fiber; less vigorous contractions; does not fatigue; aerobic (meaning reactions require O2); used for non-strenuous activities |
| What is the ratio of Fast-Twitch and Slow-Twitch muscle fiber? | People have varying percentage of each fiber type |
| What are the names of the types of proprioceptive receptors in muscles? | Muscle Spindles & Golgi Tendon Organ |
| What is a Muscle Spindle? | A type of proprioceptive receptor (lets you know where muscles are & what they are doing); located in the muscle; responds to a stretch; causes muscle contractions; responsible for the "stretch reflex" (occurs when spindles detect too intense a stretch) |
| What is the "Stretch Reflex"? | A reflex of muscle spindles; occurs when spindles detect too intense a stretch; sends afferent feedback to the spinal cord; causes contraction |
| What is a Golgi Tendon Organ? | A type of proprioceptive receptor; located in the tendons; responds to contractions; inhibits muscle contractions; acts as "brake" against excessive contractions (sends afferent feedback to the spinal cord & inhibits motor neurons) |
| What are Reflexes? | Reflexes are involuntary, consistent, and automatic responses to stimuli (ex: pupil dilation); a type of ballistic movement; behavior is usually a mixture of reflexive and non-reflexive movements |
| Reflexes are one extreme, what is at the other end of the spectrum? | Novel Motor Actions |
| What are Novel Motor Actions? | Actions that require sustained control |
| What are Central Pattern Generators? | Neural mechanisms (often in the spinal cord) that generate rhythmic patterns of motor output (ie: bird flapping its wings) |
| What is a Motor Program? | Type of Ballistic movement; fixed sequence of movements, learned or built into NS; once begun, sequence is fixed from beginning to end; automatic in sense that thinking/talking about it interferes w action (jump-shot); doesn't require conscious control |
| What is a Ballistic Movement? | Motion that proceeds as a single organized unit that cannot be redirected once begun; once initiated, they cannot be altered, corrected, or stopped |
| How do we produce complicated movements if there is only one message we can send a muscle (to contract)? | Timing & Spatial (which muscles we contract, and coordination of them); Antagonistic muscles help this |
| Why are Motor Programs useful? | They allow resources to be freed up to think about other things |
| When is the Primary Motor Cortex active? What does it do? | The PMC is active when people intend to make a movement; it does not specify the precise movement pattern (spinal cord does), just the desired outcome; specific areas of the PMC are responsible for control of specific areas on the opposite side of body |
| Where do the axons of the Primary Motor Cortex go and what do they do? | Axons from the Primary Motor Cortex connect to the brainstem and spinal cord which generate impulses that control the muscles |
| What is the role of the Posterior Parietal Cortex? | Keeps track of the position of body relative to the world; damage to this area causes difficulty coordinating movement with visual input; important for planning movement; gets touch info from Primary Somatosensory Cortex & visual info from "where" path |
| What is the role of the Premotor Cortex in movement? | Active during preparation for movement |
| What is the role of the Supplementary Motor Cortex in movement? | Organizes sequences of movements in a particular order; active seconds before the movement occurs |
| What is the role of the Prefrontal Cortex in movement? | Interprets sensory signals; represents the relationship between actions and outcomes; it decides which movements to make |
| Where were Mirror Neurons first observed & when are they active? | They were first observed in the Premotor Cortex; the ones in the Premotor Cortex are active during preparation for a movement and observing someone make the same movement; may be important for understanding, identifying, and imitating others |
| What might be important about Mirror Neurons? | They may be important for understanding, identifying and imitating others; may be involved in social behavior; unknown whether they cause or result from social behavior; could explain early mimicry |
| What is the Lateral Corticospinal Tract? Where does it originate from? What does it control? Where do axons go? | Originates from motor cortex & red nucleus; controls movements in peripheral areas (hands and feet); red nucleus mainly controls arm muscles; axons go to opposite side of spinal cord (contralateral); controls movement in limbs on opposite side of body |
| What is the Medial Corticospinal Tract? Where does it originate from? What does it control? Where do axons go? | Originates from various cortical areas, reticular formation, midbrain & vestibular nucleus; axons go to both sides of the spinal cord; allows for control of the neck, shoulders, trunk; enables turning, bending, standing up, walking |
| How do the Medulla & Spinal Cord implement movements initiated by the cortex? | Through the two Corticospinal tracts: Lateral Corticospinal Tract & Medial Corticospinal Tract |
| What is the role of the Cerebellum? | Involved in balance & coordination, rapid movements requiring aim & timing (like clapping, speaking, writing), learning new sequences of movements, shifting attention |
| Being drunk resembles to damage to which brain area? | Cerebellum; alcohol influences it very quickly |
| From where does the Cerebellum receive input? | From the Spinal Cord, Cortex, each sense, etc |
| What is the Basal Ganglia? | A collection of subcortical structures important in movement that is responsible for initiating actions that are NOT guided by a stimulus |
| What is the normal baseline state of the Basal Ganglia? Conceptually, how does the BG select a movement? | The normal baseline state of the BG is to inhibit the thalamus; BG selects a movement to make by ceasing to inhibit it (you have many potential motor sequences that are constantly being inhibited) |
| Biologically, describe the Basal Ganglia and how it exerts its power. | The BG receives dopaminergic inputs from the Substantia Nigra; receives input from the Cerebral Cortex and sends output to the thalamus, which relays information to the motor areas & prefrontal cortex |
| What is Parkinson's disease, its core problem, and its symptoms? | Primarily a movement disorder; core problem is initiating spontaneous movement in the absence of a stimulus to guide the action; symptoms include muscle tremors, rigidity, slow movements, depression risk, & cognitive impairments (memory/learning) |
| What is the biological basis of the problem in Parkinson's disease? | Caused by a gradual death of neurons in Substantia Nigra (BG receives less excitatory dopaminergic input); this makes it harder for BG to release inhibition & initiate actions |
| What are the causes of getting Parkinson's disease? | Partly genetic (especially early onset); partly environmental (ie: MPTP exposure- drug that accumulates/destroys neurons that release dopamine; pesticides with similar effects); once enough Substantia Nigra neurons are damaged, you get symptoms |
| What is the main treatment for Parkinson's disease? | L-Dopa (a dopamine precursor that can cross the blood-brain barrier) |
| What is L-Dopa? Describe its effectiveness & side effects. Is it focal or systemic? | A dopamine precursor used as main treatment for Parkinsons; can cross the blood-brain barrier; sometimes ineffective, especially in late stages; does not stop loss of SN neurons; also influences cells outside SN, unpleasant side effects (systemic) |
| What are other systemic treatments for Parkinson's (besides L-Dopa)? | Antioxidant drugs; drugs that stimulate dopamine receptors or block glutamate or adenosine receptors; neurotrophins to promote neural survival; drugs that decrease apoptosis (cell death); stimulation of cannabinoid receptors |
| What are some focal treatments that have been tried for Parkinson's? | High frequency electrical stimulation (which is invasive); Implantation of fetal neurons (which is somewhere between partially and non-effective, but stem cells may improve outcomes- our best hope) |
| Is Parkinson's characterized by too much or too little inhibition? | Parkinson's causes too much inhibition |
| Is Huntington's characterized by too much or too little inhibition? | Huntington's causes too little inhibition |
| Does Parkinson's damage the Basal Ganglia or its input? | Parkinson's damages the input to the Basal Ganglia (in the form of Substantia Nigra neurons) |
| Does Huntington's damage the Basal Ganglia or its input? | Huntington's damages the Basal Ganglia themselves |
| What is Huntington's Chorea? Its symptoms? | Neurological disorder w motor symptoms: arm jerks/ facial twitches (earliest); tremors; writhing; impaired walking&speech & non-movement issues (later) depression&anxiety, hallucinations&delusions, poor memory&judgment, alcohol&drug abuse, sexual disorder |
| What is the biologic problem in Huntington's? | Causes extensive damage to the Basal Ganglia (and other regions) |
| What are the causes of getting Huntington's? | Very strong genetic component; controlled by an autosomal dominant gene on chromosome 4; 50% chance of passing it on to child; easy, highly accurate pre-symptomatic tests can identify who will develop it |
| What is the treatment for Huntington's? | No treatment is effective in controlling symptoms or slowing the disease |
Created by:
Kelsey20
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