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301 Cards in this Set
- Front
- Back
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How does the environment play a role in genetic regulation in both the individual and population?:
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Regulatory genes react to environmental stimuli and can promote or repress the transcription of a gene. On a population level, genetic variants leading to behavior that is adaptive to the organism’s environmental conditions are selectively preserved.
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With regards to genetics, what are adaptive values?:
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Adaptive values describe the extent to which different genotypes contribute to survival in a given environment.
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What is sensation?:
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Sensation is the conversion of physical stimuli into electrical signals that are transferred through the nervous system by neurons. Sensation is a physical process.
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What is perception?:
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Perception is the use of sensory information and pre-existing knowledge to create a functional representation of the world. Perception, in contrast to sensation, involves physiological and mental processing, allowing for conscious awareness of the environment.
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What is absolute threshold?:
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Lowest intensity of a stimulus that can be sensed. With hearing, it would be the softest sound that can be reliably heard.
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What is a difference threshold?:
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aka Just Noticeable Difference, this describes the smallest difference that is sufficient for a change in a stimulus to be noticed.
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What is Weber’s law?:
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With sensation, the change required to meet the difference threshold is a certain fraction (the Weber fraction) of the originally presented stimulus. Fraction is constant for each sense, but varies across sense. High sensitivity is associated with a small Weber fraction—for a more sensitive sense organ, only a small change in the stimulus is required for the change to be detected.
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What is Signal Detection Theory?:
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Theory that focuses on how an organism differentiates important or meaningful stimuli (signals) from those that are not of interest (noise) in an environment where the distinction is ambiguous. Contrast this to Weber’s law, which studies thresholds. Sensitivity can be expressed as a comparison between the false alarm rate and the hit rate.
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How does sensitivity play a role in Signal Detection Theory?:
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Sensitivity is mediated by bias, the individual’s tendency towards or against accepting evidence of a signal. The individual consciously decides whether the evidence of a signal is sufficiently compelling.
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What is selective attention and how does it differ from divided attention?:
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It refers to the focus of attention on one particular stimulus or task at the exclusion of other stimuli. It is like the narrowing of a tunnel between sensation and perception such that only certain information is allowed to proceed. By contrast, divided attention splits perceptual resources between multiple stimuli or behaviors. It is comparable to dividing the tunnel used for selective attention into two smaller lanes.
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What are bottom-up processing and top-down processing and how do they contrast?:
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With bottom up processing, individual components of sensory information are bundled up and used in the construction of perceptions. With top-down processing, prior knowledge is utilized to make perception more efficient. Both are used as part of perception.
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What are Gestalt principles?:
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Principles that describe the criteria that are used to distinguish between figure and background, or between objects in a group and objects out of the group. Stated differently, these principles describe the top-down processing that organizes sensory information, such as visual clues, into distinct forms. When one object is recognized as a form or figure, the rest of the stimulus is perceived as the background or ground.
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What are six Gestalt principles?:
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Principle of nearness says that clusters of objects will each be perceived as a distinct group; principle of similarity points out that objects with shared features, such as shape, will likewise be perceived as a single group; Principle of common region says that objects sharing a common background are perceived as a group even if they would be separated by the principles of nearness and/or similarity; Principle of Continuity states that the brain will perceive an ambiguous signal according to its simplest form; Principle of Closure points out that we perceive whole shapes even when they are not actually present in the stimulus.
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What is the big issue with depth, motion, and constancy?:
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Depth, motion, and constancy (distinguishing between information received by the retina and changes in surrounding) are problematic because they cannot be represented accurately on the retina and thus their perception occurs only after the brain does further interpretation.
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What are the two pathways that handle visual processing and what do they entail?:
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Parallel processing and feature detection. Parallel processing is the use of multiple pathways to convey information about the same stimulus. It begins with bipolar and ganglion cells—one type of ganglion cells detects information about motion and another detects information about form of stimuli (shape and color). Feature detection involves the process of how certain cells in the visual cortex of the brain optimally respond to particular aspects of visual stimuli, such as lines of particular orientation—and these responses are integrated to form perception as a whole. Feature detection is a type of serial processing.
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What is the critical difference between parallel processing and feature detection?:
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Parallel processing involves multiple pieces of information about a stimulus being processed at the same time, whereas feature detection describes sequential processing.
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What is consciousness?:
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Consciousness can be roughly equated with awareness, such as awareness of oneself, one’s surroundings, one’s thoughts, and one’s goals.
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What is alertness and how does it differ from wakefulness?:
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Alertness can be described as a “default” state of consciousness. In a fully conscious, alert sate, the brain is able to attend to tasks and carry out goal-directed processes. A person can be awake but nit alert, which has been shown in recordings of the brain.
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What is circadian rhythm? What drives wakefulness?:
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Circadian rhythm balances wakefulness and sleep. The biological clock of the suprachiasmatic nucleus (SCN) located in the hypothalamus, regulates the timing of many of the body’s circadian rhythms, such as body temperature. SCN maintains the drive for wakefulness by inhibiting release of hormone melatonin by the pineal gland. SCN firing lowers as the day passes and the drive to sleep comes to dominate.
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Characterize the four stages of sleep?:
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Stage 1, also called light sleep, includes alpha waves. Alpha waves are associated with wakefulness, but a more relaxed wakefulness than is associated with Beta waves. Stage 2 sleep is associated with bursts of brain wave activity that indicate a full transition into sleep. Stage 3 sleep offers the first example of delta waves, which are longer than alpha waves, and reflect the transition into deep sleep. Stage 4 is the deepest sleep, and it is characterized by almost entirely delta waves.
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What are the differences between Rapid Eye Movement (REM) sleep and non-REM (NREM) sleep?:
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REM sleep is characterized by high brain activity, and characteristic eye movements. REM sleep doesn’t occur in first sleep cycle of night, but is seen in stage 1 sleep in later cycles. Brain relives stimuli during REM and consolidates information into memory. Non-REM (NREM) sleep is characterized by much lower brain activity and forms the bulk of sleep. During REM sleep, the body is immobilized.
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What is the difference between sleep terrors and nightmares?:
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Sleep terrors differ from nightmares in that sleep terrors occur in NREM sleep. Sleep terrors are also more psychologically disturbing because they involve a sense of total panic.
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What is the difference between agonists and antagonists?:
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Agonists mimic chemically similar, naturally-occurring neurotransmitters, thus enhancing their effect. Antagonists are drugs that bind to neurotransmitter receptors without activating them, undermining its normal effect.
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What are reuptake inhibitors and how do they compare to enzyme inhibitors?:
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Reuptake of neurotransmitters prevent the constant stimulation of post-synaptic receptors, and reuptake inhibitors interfere with this process so that a greater amount of neurotransmitter remains in the synapse. Enzyme inhibitors prevent the breakdown of neurotransmitters that have been taken up by the pre-synaptic neuron.
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How do stimulants and depressants differ in their behavior?:
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Stimulants raise the level of activity in the central nervous system, often by increasing the amount of monoamine neurotransmitters, such as epinephrine and dopamine, in the synapse. Depressants cause a decrease of activity in the central nervous system.
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Characterize the activity of anti-depressants that are selective serotonin reuptake inhibitors (SSRIs) vs. monoamine oxidase inhibitors (MAOIs)?:
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Selective serotonin reuptake inhibitors increase the amount of serotonin present in the synapse, whereas monoamine oxidase inhibitors interfere with the breakdown of monoamine neurotransmitters, including serotonin and norepinephrine.
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Briefly characterize the mechanism behind drug addiction?:
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The addictive potential of drugs is rooted in activity in the reward pathway within the limbic system, which is associated with both feelings of reward and pleasure that lead to cravings and addiction. By activating this pathway, addictive drugs increase levels of dopamine and feelings of reward. Over time, the pathway is altered. For example, the brain reacts to higher levels of dopamine by lowering the baseline level of dopamine, and the need for a drug is more strongly felt.
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What is declarative memory?:
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Declarative memory involves information that is consciously known, such as the memory of specific lifetime events and the knowledge of facts.
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What is non-declarative or procedural memory?:
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Memory that refers to an unconscious ability to remember how to perform a particular task.
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What is encoding?:
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Transformative process whereby memory is transformed into the type of representation that is used by that particular form of memory storage.
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What is sensory memory and what happens with it?:
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Sensory memory is the first phase in memory formation and it is temporary storage for incoming sensory stimuli. It involves process of transducing physical stimuli into electrical information that is thereby accessible to the nervous system, carried out by sensory receptors and dendritic summation. Sensory memory is either stored as short term memory or lost altogether. There is unlimited storage potential.
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What are the three steps of memory formation?:
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Sensory memory, short term memory, and long term memory.
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What is working memory and how does it differ from sensory memory?:
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Working memory is a component of short-term memory. It differs from sensory memory in that the encoding is done by rehearsal, or the repetition of a phonetic representation. Working memory also has limited storage, with research suggesting that most people can hold only 5 to 9 pieces of information in working memory at a time.
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What is long term memory and how does it differ from working memory?:
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Long term memory is more durable storage. It has unlimited storage potential and it is encoded by meaning, which means linking new information to meaningful ideas that already held in long-term memory. This contrasts with the rehearsal encoding process characteristic of working memory.
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What is neural plasticity?:
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Neural plasticity is the ability of the brain’s networks of neurons and their synapses to change. Neural plasticity allows memories to be stored as changes to networks of neurons.
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How are memories strengthened?:
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The strengthening of a neural network that represents a memory is called memory consolidation. It happens every time that a presynaptic neuron releases neurotransmitter triggering an action potential in the post-synaptic neuron, which means that memory is strengthened not just by encoding but also retrieval of memory.
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What is long-term potentiation?:
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It describes the increase in likelihood that presynaptic input will trigger an action potential in the postsynaptic neuron. LTP results when repeated stimulation by the presynaptic neuron while the postsynaptic neuron is also active leads to an increase in the strength of the excitatory postsynaptic potential that is produced by similar stimulation.
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What are semantic networks?:
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Networks of meaningfully related memories that serve to organize information and are used by long term memory.
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What is spreading activation?:
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Spreading activation is the idea that related memories are brought to mind, whereby the process of retrieving one item triggers an activation of related memories.
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What is the difference between recall and recognition in memory retrieval?:
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Recall is the retrieval of a memory ‘from scratch’, while recognition is the correct identification of information that is presented. Recognition is like picking definitions from a list, whereas recall is remembering a definition by heart.
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What are retrieval cues?:
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Retrieval cues are environmental stimuli or pieces of information that are associated in some way with the memory being sought.
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How does emotion play a role in memory retrieval?:
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Memory retrieval is strongest when the emotional state during retrieval is similar to that of memory formation.
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What role does relearning serve with memory?:
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Relearning allows for the detection of long-term memories that have become inaccessible to conscious recognition or recall and thus are experienced as lost.
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What is memory decay?:
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Memory decay describes the fading of a memory and it represents the fate of information in working memory that does not get encoded into long-term memory. Neurologically speaking, decay is the weakening of connections that make up the neural network that holds a memory.
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Contrast the primacy effect and the recency effect?:
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The primacy effect refers to the fact that memory of things at the beginning of the list tends to be strongest, whereas the recency effect refers to the fact that there is also stronger recall of items at the end of a list. Thus, items at the middle of the list tend to be the most vulnerable to decay.
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Contrast decay and forgetting?:
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Decay affects working memory and sensory memory, whereas the forgetting of information in long-term memory is often due to problems with retrieval rather than the loss of the memory altogether.
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With memory, what is the concept of interference?:
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Regarding long term memory, this is the idea that similar information prevents the retrieval of a memory.
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With memory, what is the concept of retroactive interference?:
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Regarding long term memory, this is the idea that newly learned material can prevent the successful retrieval of related older memories.
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With memory, what is the concept of proactive interference?:
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Regarding long term memory, this is the idea that previously learned material can prevent successful retrieval of more recently learned information.
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What is memory construction?:
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Memory construction is the process by which a memory is updated with new information and experiences during the retrieval process.
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What is source monitoring?:
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Source monitoring occurs when a person attributes a memory to a particular source, correctly or not, such as recalling that a story was told by a particular person—and it may lead to memory construction and even the construction of false memories.
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What parts of the brain are involved with age-related changes to memory?:
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The areas of the brain mentioned in the context of memory-the hippocampus and prefrontal cortex-can both be involved.
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What parts of the brain does Alzheimer’s affect first and what are the two types of damage involved?:
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It affects the hippocampus and the surrounding areas first. The two types of damage in the brain include amyloid plaques, which are extracellular protein deposits, and neurofibrillary tangles which are located within neurons.
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How does Korsakoff’s syndrome present and what causes it and where is damage seen?:
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It presents as a deficit in the ability to recall recent events while older memories are relatively unaffected. It is caused by a deficiency in Vitamin B1, often as a result of severe alcoholism, and it causes damage to the frontal cortex and thalamus.
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What is one of the big differences between Parkinson’s and Korsakofff’s syndrome and Alzheimers?:
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The brain damage associated with Parkinson’s is restricted to a certain area rather than being widely distributed.
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What is the key area of deterioration in Parkinson’s and what is the result?:
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Deterioration occurs within the substantia nigra, located within the midbrain, leading to impairment of motor abilities. Since the affected neurons release the affected neurotransmitter dopamine, Parkinson’s is associated with a deficiency of dopamine in this part of the brain.
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What is an action potential?
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It's a localized area of depolarization (an electrochemical impulse) that travels in a wave-like manner along an axon. Action potentials are electrochemical rather than strictly electrical b/c they rely on ion movement (not just electrons moving along copper wire).
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What is synaptic transmission?
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Synaptic transmission is the transformation of the action potential, which has traveled to the end of the axon at the synapse, into a chemical signal with the release of neurotransmitter into the synaptic cleft.
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What is the soma?
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It's the central cell body of the neuron, which contains the nucleus and is where most of the biosynthetic activity of the cell takes place.
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Characterize the relative numbers of axons and dendrites?
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Neurons have only one axon, but multiple dendrites.
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What does it mean for a neuron to be bipolar?
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It has only one dendrite.
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What does it mean for a neuron to be multipolar?
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Neurons with multiple dendrites.
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Do neurons transmit action potentials in multiple directions or one direction?
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One direction.
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What is a synaptic knob?
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The ends of axons that serve as connecting points with target cells by way of synaptic cleft.
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What is the synaptic cleft?
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It's the small space between the synaptic knob, which release chemical messengers, and the target cell, which will be affected by said messengers.
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What is the resting membrane potential?
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It's a 70 mV electrical potential across the plasma membrane, with the interior of the cell negatively charged with respect to the exterior of the cell. (Effectively the inside of the cell is -70mV)
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What are the two membrane proteins that establish the the resting membrane potential?
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1) Na+/K+ ATPase and 2) the potassium leak channels.
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How does the Na+/K+ ATPase pump work? What are its energetics?
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The Na+/K+ ATPase pumps three sodium ions out of the cell and two potassium ions into the cell, with the hydrolysis/utilization of one ATP molecule.
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What gradient does the Na+/K+ ATPase pump generate?
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It generates a sodium gradient with high sodium outside of the cell and a potassium gradient with high potassium inside the cell.
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What are leak channels? Are there more Na+ leak channels or K+ leak channels?
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Leak channels are protein channels that are open all the time. Potassium leak channels allow potassium ions (and no other cells) to flow down their gradient--and out of the cell. There are a lot more potassium leaks than sodium leak channels.
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What does it mean for cells to be polarized?
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Neuron cells are polarized in their resting state, whereby they are negative on the inside and positive on the outside. An action potential disturbs this with its wave of depolarzation.
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What is depolarization?
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Depolarization is a change in the membrane potential from the resting membrane potential of -70 mV to something less negative, or even positive potential.
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What is repolarization?
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After depolarization, repolarization returns membrane potential to normal.
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What role do voltage-gated sodium channels play in the propagation of action potentials?
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They respond to a change in membrane potential by opening to allow sodium ions (positive) to flow down their gradient, into the cell, and thus allow that section of membrane to be depolarized and become more positive. Since sodium ions flow down the interior of the axon and slightly depolarize the neighboring section of membrane as well, allowing for the wave of depolarization to keep passing down the axon
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What is the threshold potential? What it's significance?
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It's about -50 mV. Its significance is that once this threshold is reached (but not before), the voltage-gated sodium channels are fully opened, allowing sodium ions to flow into the cell, thereby bringing about depolarization of that section of membrane as its potential rises to +35mV before the channels inactivate.
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Why does the membrane repolarize after depolarization? (3 reasons)
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1) Voltage-gated sodium channels inactivate quickly after opening, stopping flow of sodium ions into cell. 2) Voltage gated potassium channels open more slowly (allowing potassium ions to exit cell) allowing the membrane to return to a negative state, and even overshooting as it goes to -90 mV, at which point they close. 3) Potassium leak channels and Na+/K+ ATPase continue to function.
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What is myelin? What effect does it have on transmission of action potential?
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Myelin is an insulating sheath that wraps the axons of many neurons. It dramatically speeds the movement of action potentials. The amount of energy consumed by the Na+K+ ATPAse is much less in unmyelinated axons because the area of the membrane is much lower.
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What are Schwann cells? What is their location?
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They are a type of glial cell that generates myelin. They are located on the PNS.
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What are the nodes of Ranvier?
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The nodes of Ranvier are periodic gaps in the myelin sheath, where action potential moves across before jumping to next Node of Ranvier.
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What is saltatory conduction?
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It's the jumping conduction of action potentials in myelinated axons.
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What are glial cells?
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They are specialized, non-neuronal cells that typically provide structural and metabolic support to neurons. They maintain a resting membrane potential but do not generate action potentials.
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What are oligodendrocytes and where are they located?
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Oligodendrocytes form myelin and increase speed of conduction of axon potentials along axon. They are located on the CNS.
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What are astrocytes and where are they located?
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Astrocytes guide neuronal development and they regulate synaptic communication via regulation of neurotransmitter levels. They are located on the CNS.
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What are microglia and where are they located?
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Microglia remove dead cells and debris and they are located on the CNS.
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What are ependymal cells and where are they located?
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They produce and circulate cerebrospinal fluid. They are located on the CNS.
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What is equilibrium potential of membranes?
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Equilibrium potential is the membrane potential at which the driving force of ion gradients does not exist. Different ions have different gradients. Sodium's is +50mV; potassium's is -90 mV.
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What is the formula for calculation the equilibrium potential for an ion?
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It's a variation of Nernst's equation. Eion= (RT/zF) ln ([X]outside/[X]inside), where R is the universal gas constant, T is the temperature in Kelvin, z is the valence of the ion, F is Faraday’s constant and the Xs capture the concentration inside and outside the membrane.
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What does it mean for a neuron to be refractory?
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It means that it's nonresponsive to membrane depolarization and unable to transmit another action potential.
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What is the absolute refractory period? What happens with voltage gated sodium channels during this time?
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It's the period during which a neuron will not fire another action potential, no matter how strong a membrane depolarization is induced. During this time, voltage gated sodium channels have been inactivated (not same as closed) after depolarization. They can only open again after membrane potential reaches the resting potential and the Na+ channels have returned to their 'closed' state.
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What is the relative refractory period? What happens to the voltage-gated sodium channels during this time?
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During the relative refractory period, a neuorn can be induced to transmit an action potential, but the depolarization required is greater than normal because the membrane is hyperpolarized. In this instant, the membrane potential is more negative than the resting potential, because the voltage-gated potassium channels have not closed yet. The larger negative value means that a larger stimulus would be required to open the sodium channels during this time?
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What does it mean if the membrane is hyperpolarized?
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It's even more negative than resting. In other words, it's -90 when it's normally -70 mV.
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What is a synapse?
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A synapse is a junction between the axon terminus of a neuron and the dendrites, soma, or axon of a second neuron.
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What are the two types of synapses?
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Electrical synapses and chemical synapses.
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What are electrical synapses and where are they common?
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Electrical synapses occur when the cytoplasms of two cells are joined by gap junctions. If two cells are joined by an electrical synapse, an action potential will spread directly from one cell to the other. They are common in smooth and cardiac muscle, but they are not common in the nervous system.
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What are chemical synapses and where are they common?
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Chemical synapses are found at the end of axons where they meet their target cell in the nervous system. They convert an action potential into a chemical signal.
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How are signals transmitted through a chemical synapses? (8 steps)
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1) An action potential reaches the end of an axon, the synaptic knob. 2) Depolarization of the presynaptic membrane opens voltage-gated calcium channels. 3) Calcium flows into the presynaptic cell, causing the exocytosis of the neurotransmitter stored in vesicle cells. 4) Neurotransmitter molecules diffuse across the narrow synaptic cleft (space between cells). 5) Neurotransmitters bind to receptor proteins in postsynaptic membrane. These receptors are ligand-gated ion channels. 6) The opening of the ligand-gated ion channels in the postsynaptic celll alters membrane polarization. 7) If membrane depolarization of postsynaptic cell reaches the threshold of the voltage-gated sodium channels, an action potential is initiated. 8) Neurotransmitter in the synaptic cleft is degraded and/or removed to terminate the signal.
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Give an example of a chemical synpase and what it's neurotransmitter is? What degrades this neurotransmitter?
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Chemical synapse is seen in the neuromuscular junction between neurons and skeletal muscle. The neurotransmitter released is acetylcholine (Ach) and it is degraded by acetylcholinesterase (Ache).
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Beyond acetylcholine, what are four other common neurotransmitters?
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Gamma-aminobutyric acid (GABA); serotonin; dopamine; norepinephrine.
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What does it mean if a neurotransmitter is excitatory?
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It binds with a receptor that opens a channel that depolarizes (makes more positive) the postsynaptic membrane. (e.g. Acetylcholine)
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What does it mean if a neurotransmitter is inhibitory?
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It means that the neurotransmitter binds with a receptor that makes the postsynaptic membrane more negative than the resting potential--in other words it hyperpolarizes it
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Do the speed and and magnitude of depolarization brought about by an action potential vary from one to the other?
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They do not, because the action potential is an "all or nothing" event.
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What is the regulated step in the nervous system?
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The regulated step in the nervous system is whether or not a neuron will fire an action potential.
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What is summation?
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Summation is the idea that stimuli are added and this collective addition of the effects of all the synapses impinging on a neuron, both excitatory and inhibitory, determines whether a postsynaptic neuron will fire an action potential.
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What are excitatory postsynaptic potentials (EPSPs)?
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They are the potentials (more positive generally) brought about by excitatory neurotransmitters acting on receptors in post-synaptic membrane.
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What are inhibitory postsynaptic potentials (IPSPs)?
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They are the potentials (more negative generally) brought about by inhibitory neurotransmitters acting on receptors in post-synaptic membrane.
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What part of the nervous system is charged with carrying out the sensory component of receiving information?
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PNS. Peripheral Nervous System.
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What part of the nervous system is charged with processing information?
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The integrative function is carried out by the CNS, central nervous system.
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What part of the nervous system is charged with acting on information?
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The motor function--it's carried out by the PNS, peripheral nervous system.
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What are efferent nurons? Where do they carry information from and to?
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Efferent neurons are motor neurons that carry information from the nervous system towards organs (effectors) that can act up on that information.
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What are effectors?
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Organs (like glands and muscles) that can act upon the information sent them by the efferent neurons.
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What are afferent neurons?
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Afferent neurons are sensory neurons which carry information toward the central nervous system.
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Are motor neurons afferent or efferent?
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Efferent.
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Are sensory neurons afferent or efferent?
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Afferent.
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What is a reflex?
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A reflex is a direct motor response to sensory input which occurs without conscious thought, generally without any involvement of the brain at all.
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What happens during the muscle stretch reflex?
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A sensory neuron detects the stretching of a muscle--and this sensory neuron has a long dendrite and a long axon, which transmit an impulse to a motor neuron cell body in the spinal cord. This motor neuron's axon synapses with the muscle (quadriceps) that was stretched--and causes it to contract. It also synapses with an inhibitory interneuron which causes the hamstring to relax.
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What is a monosynaptic reflex arc?
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A reflex that involves only two neurons and one synapse.
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What is an inhibitory interneuron?
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Short neurons which form an inhibitory synapse--they stimulate relaxation. They are commonly seen in hamstring.
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What is reciprocal inhibition?
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It's the concurrent contraction via one neuron, and relaxation via another neuron.
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What are the two principal divisions of the nervous system and what do they encapsulate?
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1) Central Nervous System (CNS), which encapsulates the brain and spinal cord. 2) Peripheral Nervous System (PNS), encapsulate all nerves and sensory structures outside of the brain and spinal control (e.g. All axons, dendrites, and cell bodies etc.).
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What are the two divisions within the PNS and what do they encapsulate?
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1) Somatic division concerns conscious sensation and deliberate, voluntary movement of skeletal muscle. 2)Autonomic division concerns involuntary control of glands and smooth muscle.
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What are the two divisions within the autonomic system and what impulses do each respond to?
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Autonomic is divided into 1) Sympathetic, which is "fight or flight" and 2) Parasympathetic, which "rest and digest."
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What are nuclei in the nervous system?
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They are structures of bunched together neuronal cell bodies, found within the central nervous system.
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What are ganglia?
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They are somas located outside the central nervous system.
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Are most neuronal cell bodies found with the CNS or elsewhere in the body?
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They are found in the CNS.
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What are the broad components of the brain?
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1) Hindbrain (or Rhombencephalon); 2) Midbrain or (mesencephalon); 3) Forebrain or prosencephalon.
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What is the cerebrospinal fluid?
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It's a clear liquid that covers the whole brain and spinal cord that serves various function such as shock absorption and exchange of nutrients & waste.
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Characterize the spinal cord in 2 points?
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1) Spine relays most data to the brain for processing, but the spinal cord is also a site for information integration and processing. 2) The spine is also responsible for simple reflexes and primitive processes (like walking, urination, sex organ function)
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What does the hindbrain consist of?
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The medulla, the pons, and the cerebellum.
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What does the medulla do?
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It regulates vital involuntary and autonomic functions such as blood pressure and digestive functions (vomiting). It's located below the pons.
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What do the pons do?
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The pons plays a role in balance and antigravity posture and controls some autonomic function and co-ordinates movement.
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What does the cerebellum do?
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It is the integrating center for movement coordination Damage to the cerebellum results in poor hand-eye coordination and balance.
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What does the midbrain do?
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It serves to organize eye function. Specifically, it is a relay for visual and auditory information and contains much of the reticular activating system (RAS), which is responsible for arousal or wakefulness.
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What does the brainstem consist of?
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It consists of the medulla, pons, and midbrain--and this brainstem contains processing centers to relay information to or from the cerebellum and cerebrum.
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What does the forebrain consist of?
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The diencephalon and the telencephalon.
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What does the diencephalon consist of?
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The diencephalon consists of the thalamus and hypothalamus.
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What does the thalamus do?
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The thalamus contains relay and processing centers for sensory information.
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What does the hypothalamus do (3 big things)
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1) Centers for controlling emotions and homeostasis/autonomic functions. 2) It has a major role in hormone production and release. 3) It is the primary link between the nervous and endocrine systems, and because it controls the pituitary gland, it's the fundamental control center for the endocrine system.
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What does the telencephalon consist of?
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It consists of two separate cerebral hemispheres.
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What does the corpus callosum consist of and what does it do?
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It consists of a thick bundle of axons and it connects the two cerebral hemispheres.
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What does the cerebrum consist of?
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The cerebrum is the largest region of the human brain and consists of the large, paired cerebral hemispheres called the cerebral cortex.
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What are the divisions of the cerebral cortex?
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1) Frontal lobes 2) Parietal lobes 3) Temporal Lobes 4) Occiptial Lobes
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What role do do the frontal lobes serve?
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The frontal lobes initiate all voluntary movement and are involved in complex reasoning skills and problem solving.
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What role do the parietal lobes serve?
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The parietal lobes are involved in general sensations (touch, temperature etc.) and taste
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What role do the temporal lobes serve?
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The temporal lobes process auditory and olfactory sensation and are involved in short-term memory, language comprehension, and emotion.
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What role do the occipital lobes serve?
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The occipital lobes process visual information.
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What role do the basal nuclei play?
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They function in voluntary motor control and procedural learning related to habits. The basal nuclei and cerebellum work together to process and co-ordinate movement initiated by the primary motor cortex; the basal nuclei are inhibitory (preventing excess movement) and the cerebellum is excitatory.
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What does the limbic system consist of and what function does it serve?
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The limbic system consists of various substructures including the amygdala and the hippocampus. It is important in emotion and memory.
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How do neurons enter and exit the CNS?
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They are carried by the 12 pairs of cranial nerves and 31 pairs of spinal nerves.
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What do cranial nerves do?
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Cranial nerves convey sensory and motor information to and from the brainstem.
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What do spinal nerves do?
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Spinal nerves convey sensory and motor information to and from the spinal cord.
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Is the Vagus nerve cranial or spinal? Is it part of the sympathetic or parasympathetic part of the autonomic nervous system?
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It's cranial--and it's part of the parasympathetic division of the autonomic nervous system.
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What are the effects of the vagus nerve on the heart and GI tract?
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It decreases heart rate and increases GI activity.
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What do somatic neurons innervate? What do they use as a neurotransmitter? Where are their cell bodies?
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All somatic motor neurons innervate skeletal muscle cells. The use Ach as their neurotransmitter. They have their cell bodies in the brain stem or the ventral (front) portion of the spinal cord.
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What do sensory neurons consist of?
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All sensory neurons haave a long dendrite extending from a sensory receptor toward the soma, which is located just outside the CNS in a dorsal root ganglion. The dorsal root ganglia are protected within the vertebral column but are outside the meninges, and thus outside the CNS
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In all somatic sensory neurons, where is the first synapse?
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In the CNS.
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What do the efferents of the autonomic (sympathetic and parasympathetic) systems consist of?
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They consist of two neurons--a preganglionic and postganglionic neuron.
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Where is the autonomic preganglionic neuron located and where does it send its axon?
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It has its cell body in the brainstem or spinal cord. It sends an axon to an autonomic ganglion, located outside the spinal column. In the ganglion, this axon synapses with a postganglionic neuron.
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Where does the autonomic postganglionic neuron send its axon?
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The postganglionic neuron sends an axon to an effector (smooth muscle or gland).
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What do all autonomic preganglionic neurons release as their neurotransmitter?
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Acetylcholine
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What do all parasympathetic postganglionic neurons release as their neurotransmitter?
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Acetylcholine
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What do nearly all sympathetic postganglionic neurons release as their neurotransmitter?
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Norepinephrine.
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What are somatic effectors?
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Skeletal muscles.
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What are autonomic effectors?
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Autonomic effectors include all visceral organs (heart, bladder, stomach, blood vessels etc.)
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What is the location of the preganglionic soma in the sympathetic system?
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They are thoracolumbular=in the thoracic and lumbar spinal cord.
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What is the location of the preganglionic soma in the parasympathetic system?
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They are craniosacral=brainstem and sacral spinal cord.
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Characterize the preganglionic axon's length in the sympathetic system.
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They are short.
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Characterize the preganglionic axon's length in the parasympathetic system.
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They are long.
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Characterize the location of the ganglia in the sympathetic system?
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They are close to the spinal cord and far from the target.
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Characterize the location of the ganglia in the parasympathetic system?
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They are farther from the cord, and close to the target.
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Characterize the length of the postganglionic axon in the sympathetic system?
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Long.
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Characterize the length of the postganglionic axon in the parasympathetic system?
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Short.
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Is epinephrine a hormone or a neurotransmitter?
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It's a hormone because it's released into the blood by a ductless gland (Adrenal medulla). Yet in many ways, it behaves like a neurotransmitter because it elicits its effects quickly and they are quite short-lived.
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What is the difference between epinephrine and norepinephrine?
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Epinephrine is a hormone and it's a slightly modified version of norepinephrine; norepinephrine is a neurotransmitter.
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How many adrenal glands are there?
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Four total--two above each kidney.
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What are the key parts of the adrenal gland?
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The cortex and the medulla.
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What hormones does the cortex release?
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1) Glucocorticoids (Cortisol being the main one) 2) Mineralcorticoids (the main one is aldosterone) and 3) some sex hormones.
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Compare and contrast sensation and perception?
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Sensation is the act of receiving information; perception is the act of organizing, assimilating, and interpreting the sensory input into meaningful information.
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What are exteroreceptors?
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They detect stimuli from the outside world.
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What are interoreceptors?
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They respond to internal stimuli.
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What are mechanoreceptors and what are two examples of them?
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Mechanoreceptors respond to mechanical disturbances. Two important examples include Pacinian corpuscles, which are pressure sensors located deep in the skin and auditory hair cells in the cochlea of the inner ear.
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What are chemoreceptors?
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Chemoreceptors, such as olfactory receptors and gustatory receptors (taste buds), respond to particular chemicals.
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What are nocireceptors?
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Nocireceptors are pain receptors, and they are stimulated by tissue injury by detecting chemical sisgns of tissue damage.
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What are baroreceptors?
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Baroreceptors sense blood pressure and relay that information to brain so proper blood pressure can be maintained.
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What are thermoreceptors?
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Thermoreceptors are stimulated by changes in temperature.
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What are electromagnetic receptors? What are two examples in humans?
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Electromagnetic receptors are stimulated by electromagnetic waves. Two key examples in humans are the rod and cone cells of the retina of the eye.
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What is adaptation?
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Adaptation is a decrease in firing frequency when the intensity of a stimulus remains constant.
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What are proprioceptors?
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It's a broad category of receptors that refer to awareness of body part position.
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What is a muscle spindle?
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It's a mechanoreceptor in the category of proprioceptors that is specialized to detect muscle stretch.
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Beyond the muscle spindle, what are two other types of proprioceptors?
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1) Golgi tendon organs, which monitor tension in the tendons. 2) Joint capsule receptors, which detect pressure, tension, and movement in the joints.
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Where are the olfactory receptors that carry out olfaction?
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They are on the roof of the nasopharynx (nasal cavity).
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What are the olfactory bulbs?
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They are located in the temporal lobe of the brain near the limbic system and they are endpoint for olfactory nerves, working in olfaction.
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What does the outer ear consist of?
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It consists of the auricle/pinna and the external auditory canal.
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What divides the middle ear from the outer ear?
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The ear drum or tympanic membrane.
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What does the middle ear consist of?
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It consists of the ossicles--the three small bones called the malleus, incus, and stapes (SIM).
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What divides the inner ear from the middle ear?
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The oval window is the membrane that divides the middle and inner ear. The stapes attaches to the oval window.
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What are the structures of the inner ear?
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The cochlea, the semicircular canals, the utricle, and the saccule.
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How does hearing work?
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Sound waves-->auricle-->external auditory canal-->tympanic membrane-->malleus-->incus-->stapes-->oval window-->perilymph-->endolymph--> pressure waves in endolymph cause vibration of basilar membrane--> basilar membrane is covered with auditory hair cells that bend during vibration across tectorial membrane and this displacement opens ion channels on hairs, leading to neurotransmitter release-->Dendrites from bipolar auditory afferent neurons are stimulated by this neurotransmitter and sound vibrations are thus converted into nerve impulses.
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What is the name given to the basilar membrane, the auditory hair caells and the tectorial membrane together? What is its significance?
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Organ of Corti. Organ of corti in cochlea is the primary site at which auditory stimuli are detected.
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How is pitch determined within the ear? How are low frequency sounds distinguished from higher frequency sounds?
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Pitch (frequency) of sound is distinguished by which regions of the basilar membrane vibrate, stimulating different auditory neurons. Low frequency (longest wavelength) sounds stimulate hair cells at the apex of the cochlea, farthest from oval window, and high frequency sounds stimulate hair cells at the base of the cochlea, near oval window.
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How is loudness distinguished in the ear?
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Loudness of sound is determined by the amplitude of vibration. Larger vibrations cause more frequent action potentials in auditory neurons.
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Where are sound stimuli processed in the brain?
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They are processed in the auditory cortex, in the temporal lobe.
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What part of the ear is responsible for balance? What is it composed of?
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Vestibular complex. It is composed of the semicircular canals, the utricle, the saccule, and the ampullae.
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How is information gathered by motion-detecting hairs in vestibular complex relayed for processing?
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The vestibular complex is innervated by afferent neurons--and these send balance information to the pons, cerebellum, and other areas.
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What types of receptors does the retina have on it? What do these synapse with?
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Rods and Cones. They synapse with bipolar cells (only one axon and dendrite) that in turn synapse with ganglion cells, whose axons comprise the optic nerve.
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What controls the curvature of the eye's lens?
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The ciliary muscle.
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Where is the fovea centralis found? What kind of cells does it have and why is it important?
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Fovea centralis (focal point) is in the center of the macular, in the retina. It contains only cone cells and is responsible for extreme visual acuity.
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What is noteworthy about what rods and cones are made up of?
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They contain special pigment proteins (an Opsin, bound to a molecule of Retinal, which is derived from vitamin A) that change their tertiary structure upon absorbing light.
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What neurotransmitter do rods and cones release in the dark on the bipolar cells that they synapse with, inhibiting them from firing?
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Glutamate
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What happens to rods and cones once exposed to a light photon?
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In the dark, retinal has several trans double bonds and one cis double bond. In this conformation, retinal and its associated opsin keep a sodium channel open. Once it has absorbed a photon of light, retinal is converted to the all-trans form, triggering a series of reactions to close soidum channel and the cell hyperpolarizes. Concurrently, rods and cones stop releasing glutamate, which removes an inhibitory effect--allowing the cells to be capable of being depolarized. Their depolarization causes the depolarization of the ganglion cells. All of the of axons of the ganglion cells together make up the optic nerve to the brain.
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What type of cell is responsible for night vision?
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Rods.
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What type of cell is responsible for color and high-acuity vision?
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Cones.
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What is emmetropia?
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Normal vision.
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What is myopia?
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Nearsightedness. Myopics can see images that are near, but have trouble seeing images that are far away.
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What is the problem inherent to myopia and how can it be corrected?
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Myopics have too much curvature on the lens, causing the image to be focused in front of the retina. It can be corrected by a concave (diverging) lens, which will cause the light rays to diverge slightly before they reach the cornea.
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What is hyperopia?
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Farsightedness. Hyperopic cans see images that farther away, but have trouble seeing images that are nearby.
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What is the problem inherent to hyperopia and how can it be corrected?
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Hyperopics have the problem of too little curvature in the lens, resulting in the image being focused behind the retina. Hyperopia can be corrected with a convex (converging) lens which causes light to converge before they reach the cornea.
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What is presbyopia? What does it result from?
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Presbyopia is an inability to focus/accomodate. It results from loss of flexibility of the lens, which occurs with aging.
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What is parallel processing?
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It's a mechanism utilized by the brain, whereby many aspects of a visual stimulus are processed simultaneously rather than in a step-by-step or serial fashion.
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What is absolute threshold?
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It's the minimum stimulus intensity required to activate a sensory receptor 50% of the time (and thus detect a sensation). (Think about it as the softest tone, the dimmest light.)
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What is the difference threshold?
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It's the minimum noticeable difference between any two sensory stimuli, 50% of the time.
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What is Weber's law?
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Weber's law suggests that two stimuli must differ by a constant proportion in order for their difference to be perceptible. The exact proportion can vary by stimulus. Light has a 8% difference threshold; weight has a 2% difference threshold.
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What is Gestalt theory with regards to senses?
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Gestalt is the German word for 'whole'. German psychologists believe the whole exceeds the sum of its parts--and that beyond merely perceiving individual components, humans perceive the whole object.
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What is a primary connection between the nervous and endocrine systems?
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Hypothalmic-pituitary axis.
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What is a hormone?
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A molecule which is secreted into the bloodstream by an endocrine gland, and which has its effects upon distant target cells possessing the appropriate receptor.
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What is an endocrine gland?
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It's a ductless gland whose secretory products are picked up by the capillaries supplying blood to the region.
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What is an exocrine gland?
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It's a gland that secretes its products into the external environment by way of ducts, which empty into the gastrointestinal lumen or the external world.
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What is a hormone receptor?
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It's a polypeptide that possesses a ligand-specific receptor binding site--that binds specific ligands (hormones).
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What is autocrine activity?
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It's the scenario where signalling molecules modify the activity of the cell which secreted them. E.g. A T-cell secretes interleukin-2, which binds to receptors on the same T-cell and stimulates increased activity.
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What are the two classes of hormones and where do they bind?
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1) Hydrophilic hormones, such as peptides and amino-acid derivatives, must bind to receptors on the cell surface. 2) Hydrophobic hormones, such as steroid hormones, must bind to receptors in the cellular interior.
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Where are peptide hormones synthesized? Modified? Stored?
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They are synthesized in the rough ER. They are modified in the Golgi. They are stored in vesicles until they are needed.
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How do peptides communicate with the interior of the target cell?
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Secondary messenger cascade.
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How quickly do peptide hormones operate? How long do their effects last?
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They operate quickly, modifying the activity of existing enzymes in the cytoplasm, and their effects are exerted rapidly, minutes to hours from the time of secretion. The duration of their effects is brief.
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What are amino acid derivative hormones derived from?
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They are derived from single amino acids and contain no peptide bonds. Tyrosine, for example, is the parent amino acid for the catecholamines (includes epinephrine) and the thyroid hormones.
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What is one of the most noteworthy examples of the catecholamines?
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Epinephrine.
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Of the catecholamines and the thyroid hormones, which one behaves like peptide hormones and which one behaves like steroid hormones?
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Catecholamines behave like peptide hormones; thyroid hormones behave like steroid hormones.
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Describe epinephrine and how it works?
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Epinephrine is a small cyclic molecule. It binds to cell-surface receptors to trigger a cascade of events that produces the second messenger cyclic adenosine monophosphate (cAMP) and activates protein kinases in the cytoplasm.
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Describe thyroid hormones and how they work?
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Thyroid hormones incorporate iodine into their structure. They enter cells, bind to the DNA, and activate transcription of genes involved in energy mobilization.
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Where are steroids synthesized? How is their release regulated?
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Steroids are synthesized in the smooth ER. Their release is regulated by the fact that they are synthesized only when needed and then used immediately--they are not stored.
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How do steroids work? 2 pts.
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They diffuse through the plasma membrane to bind with a receptor in the cytoplasm (or directly in nucleus). Once bound, the steroid hormone-receptor complex is transported into the nucleus, where it acts as a sequence-specific regulator of DNA transcription.
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What is the timing/effect of steroids?
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It's slow and long-lasting.
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Coompare the sizes of peptide hormones (two types) and steroids (one type)
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Among the peptide hormones, polypeptides are large and amino acid derivatives are small. Steroid hormones are small.
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How do we denote the concentration of a species X in the aqueous portion of the bloodstream?
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Serum [X]
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What are tropic hormones?
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Tropic hormones are hormones that regulate hormones.
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What is an example of tropic hormone? How does it work?
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Adrenocorticotropic Hormone (ACTH) is an example of a tropic hormone. It's secreted by the anterior pituitary and it stimulates the release of cortisol, by stimulating the increased activity of the portion of the adrenal gland called the cortex. When cortisol is needed, ACTH is secreted, and when the level of cortisol increases sufficiently, ACTH secretion slows.
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Characterize the nature of most feedback in the endocrine system?
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Most feedback is negative because it's an inhibitory loop. The result of ACTH hormone secretion inhibits further secretion of hormone (cortisol).
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What portion of the brain controls the endocrine system? How does it do this?
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The hypothalamus controls the endocrine system, by releasing "Releasing and Inhibiting Factors/Hormones" that regulate other tropic hormones.
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What hormone does the hypothalamus release to regulate the cortisol pathway?
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It releases corticotropin releasing hormone (CRH), which targets the anterior pituitary, which releases ACTH, which targets the adrenal cortex, which releases cortisol. Cortisol is a negative feedback inhibitor that acts on the hypothalamus and adrenal cortex.
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How does hypothalamus get its hormones to the anterior pituitary?
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With the hypothalamic-pituitary portal system.
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What's another name for the pituitary gland?
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Hypophysis.
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What's another name for the anterior pituitary?
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Adenohypophysis
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What's another name for the posterior pituitary?
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Neurohypophysis
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Compare the anterior and posterior pituitary?
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The anterior pituitary is a normal endocrine gland; the posterior pituitary is composed of axons which descend from the hypothalamus.
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What are neuroendocrine cells and where do we see them in action?
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Neuroendocrine cells are neurons which secrete hormones into the bloodstream. They are seen in the hypothalamic neurons which send axons down to the posterior pituitary.
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Where are the hormones released by the posterior pituitary made?
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They are made in nerve cell bodies in the hypothalamus and transported down the axons to the posterior pituitary.
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What category of hormones do the hypothalamus and pituitary hormone manufacture?
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Peptide hormones.
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How and where is thyroid hormone formed?
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It's formed from the amino acid tyrosine in the thyroid gland and comes in two forms--a version with three iodine atoms and a version with four iodine atoms.
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How does thyroid hormone work and what does it do?
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Thyroid hormone binds a receptor in the cytoplasm of cells that then regulates the transcription in the nucleus. The effect of this regulation is to increase the overall metabolic rate and body temperature--and in children, to stimulate growth.
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What purpose does cortisol serve?
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It helps the body deal with stress. Cortisol mobilizes glycogen and fat stores to provide energy during stress, and also increases the consumption of proteins for energy.
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Would an inhibitor of protein synthesis block the action of thyroid hormone?
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Yes. The thyroid hormone binds to a receptor that regulates transcription. The mRNA stimulated by thyroid hormone receptor in the nucleus must be processed and translated before the effects of thyroid hormone can become evident.
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What hormone does the hypothalamus release? What is its target and what does it do?
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Releasing and inhibiting factors. It targets the anterior pituitary and it modifies AP's activity.
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What releases Growth Hormone and what does GH do?
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The Anterior Pituitary. GH increases bone & muscle growth and it increases cell turnover rate.
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What releases prolactin? What does prolactin target and what does it do?
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Prolactin is released by the anterior pituitary. It targets the mammary glands and it brings about milk production.
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What releases Thyroid Stimulating Hormone? What does TSH target and what does it do?
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Anterior Pituitary. It targets the thyroid and it increases the synthesis and release of thyroid hormone.
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What releases adrenocorticotropic hormone (ACTH)? What does it target and what does it do?
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Anterior Pituitary. It targets the adrenal cortex. This stimulates the growth and secretory activity of the adrenal cortex.
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What releases luteinizing hormone? What does it target and what is it involved in?
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Anterior Pituitary. In women, it targets the ovaries, and is involved in ovulation. In men, it targets the testes, and it is involved in testosterone synthesis.
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What releases follicle stimulating hormone? What does it target and what is it involved in?
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Anterior Pituitary. With women, it targets the ovary and is involved in follicle development. With men, it targets the testes and is involved in spermatogenesis.
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What releases ADH and what does ADH target and do? What's another name for ADH?
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Posterior Pituitary releases ADH. Another name for it is Vasopressin. ADH targets the kidney and brings about water retention.
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What releases oxytocin and what does oxytocin do?
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Oxytocin targets the breast, to bring about milk letdown, and it targets the uterus to bring about contraction.
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Where is thyroid hormone generated? What does it do?
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Thyroid hormone is generated in the thyroid. In children, it's necessary for physical and mental development. In adults, it increases metabolic rate and temperature.
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Where is calcitonin generated? What does it target and what does it do?
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Calcitonin is generated in the thyroid C cells. It targets the bones and kidneys. It lowers serum (Ca2+).
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What is parathyroid hormone generated? What does it target and what does it do?
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It's produced in the parathyroid. It targets bone, kidney, small intestine. It raises serum (Ca2+).
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Where is thymusin generated? What does it do?
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It's generated in the thymus. It's important for T cell development during childhood.
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Where is epinephrine generated? What kind of hormone is it? What does it do?
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Epinephrine is a modified amino acid that's generated in the adrenal medulla. It speeds up the sympathetic stress response.
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Where is cortisol generated? What kind of hormone is it? What does it do?
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Cortisol is generated in the adrenal cortex. (It's a glucocorticoid, and it's a steroid hormone.) It plays a role in longer-term stress response: it raises blood glucose, it raises protein ctabolism, it lowers inflammation and immunity and many other things.
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Where is aldosterone generated? What kind of hormone is it? What does it target and do?
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Aldosterone, a mineralcorticoid, is generated in the adrenal cotex. It's a steroid. It targets the kidneys and it raises Na+ reabsorption to raise blood pressure.
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Where are the sex steroids generated? What is their significance?
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The sex steroids are generated in the adrenal cortex. They are not normally important, but an adrenal tumor can overproudce these, causing masculinization or feminization.
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Where is insulin generated? What kind of hormone is it? What does it do?
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Insulin is a peptide hormone generated in the Beta cells of the islets of Langerhans in the pancreas. Insulin lowers blood sugar and increases glycogen and fat storage.
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Where is glucagon generated? What kind of hormone is it? What does it do?
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Glucagon is a peptide hormone, generated in the alpha cells of the islets ofLangerhans in the pancreas. Glucagon raises blood glucose levels and decreases glycogen and fat storage.
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What is somatostatin? What kind of hormone is it? Where is it generated and what does it do?
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Somatostatin is a peptide hormone that the delta cells of the islets of langerhans in the pancreas produce. It inhibits many digestive processes.
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What is testosterone? What kind of hormone is it? Where is it produced and what does it do?
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Testosterone is a steroid hormone. It's produced in the testes and it's responsible for male characteristics and spermatogenesis.
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What is estrogen? What kind of hormone is it? Where is it produced and what does it do?
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It's a steroid hormone, produced in the ovaries. It's responsible for female characteristics and endometrial growth.
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What is progesterone? What kind of hormone is it? Where is it produced and what does it do?
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It's a steroid hormone produced in the ovaries/placenta. It's responsible for endometrial secretion and it's part of pregnancy.
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What is ANF? What kind of hormone is it and where is it produced? What does it target and what does it do?
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Atrial Natriuretic Factor is a peptide hormone produced by the heart. It targets the kidney and it increases urination to lower blood pressure.
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What is erythopoietin? What kind of hormone is it and where is it produced? What does it do?
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Erythopoietin is a peptide hormone. It is produced in the kidney. It targets the bone marrow and increases RBC synthesis.
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What effect does the sympathetic system stimulation have on motility in the digestive system?
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It inhibits (inhibiting digestion).
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What effect does parasympathetic system stimulation have on the digestive sphincters?
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It relaxes them
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What effect does sympathetic system stimulation have on the digestive sphincters?
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It contracts them.
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What effect does parasympathetic system stimulation have on the bladder?
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Contraction--stimulation urination
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What effect does parasympathetic system stimulation have on the uretal sphincter?
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Relaxation-stimulation of urination
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What effect does the sympathetic system stimulation have on the bladder?
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Relaxation--Inhibits urination.
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What effect does sympathetic system stimulation have on the uretal sphincter?
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Contraction--inhibits urination
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What effect does sympathetic system stimulation have on bronchial smooth muscle?
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Relaxation--opens airways.
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What effect does parasympathetic system stimulation have on bronchial smooth muscle?
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Constriction--closes airways.
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What effect does parasympathetic system stimulation have on the pupil?
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Constriction.
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What effect does parasympathetic system stimulation have on the muscles controlling lens?
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Near Vision Accomodation.
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What effect does sympathetic system stimulation have on the pupil?
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Dilation.
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What effect does sympathetic system stimulation on the muscles controlling lens?
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Accomodation for far vision.
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What effect does parasympathetic system stimulation have on the adrenal medulla?
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It has none.
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What effect does the sympathetic system stimulation have on the adrenal medulla?
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It stimulates the release of epinephrine.
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What effect does parasympathetic system stimulation have on the genitals?
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It stimulates erection/lubrication.
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What effect does sympathetic system stimulation have on the genitals?
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It stimulates ejaculation/orgasm.
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