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39 Cards in this Set
- Front
- Back
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name the 3 main parts of the neuron and describe their function |
cell body (soma)- contains the biochemical structures needed to keep the neuron alive, and its nucleus carries the genetic code info that determines how the cell develops and functions dendrites- collect messages from neighbouring neutrons and send them to the cell body axon-conducts electrical impulses away from the cell body to other neurons, muscles or glands |
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which structural characteristics permit the many possible interconnections amount neurons? |
axon terminals |
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how do glial cells differ from neurons? what 3 functions do they have in the nervous system? |
glial cells surround neurons and hold them in place. glial cells also manufacture nutrient chemicals that neurons need, from the myelin sheath around some axons, and absorb toxins and waste materials that might damage neurons. |
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what causes the negative resting potential of neurons? when is a neuron said to be in a state of polarization? |
the high concentration of sodium ions in the fluid outside the cell, together with the negatively charged protein ions inside, result in an uneven distribution of positive and negative ions that makes the interior of the cell negative compared to the outside. this internal difference of around 70 millivolts is called the neuron's resting potential, at rest, the neuron is said to be in a state of polarization |
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what chemical changes cause the process of depolarization that create graded and action potentials? how do these potentials differ? |
an action potential is a sudden reversal in the neuron's membrane voltage, during which the membrane voltage momentarily moves from -70 millivolts to +40 millivolts. this shift from negative to positive voltage is called depolarization |
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what is the nature and importance of the myelin sheath? which disorder results from inadequate myelinization? |
electrical conduction can skip from node to need, and these great leaps from one gap to another account for high conduction speeds of more than 300 km/hr. multiple sclerosis occurs when the persons own immune system attacks the myelin sheath |
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how do neurotransmitters achieve the processes of excitation and inhibition of postsynaptic neurons? |
excitation-this stimulation, alone or in combination with activity at other excitatory synapses on the dendrites or the cell body. may exceed the action potential threshold and cause the postsynaptic neuron to fire an action potential. inhibitory- by stimulating ion channels that allow positively charged K- IONS TO FLOW OUT OF THE NEURON OR NEGATIVELY CHARGED IONS,SUCH AS Cl-, to flow into the neuron. this makes the membrane potential even more negative. |
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describe 2 methods by which neurotransmitter molecules are deactivated at the synapse |
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describe the roles of acetylcholine, dopamine, serotonin and endorphins in psychological functions |
acetylcholine (ACh)- underproduction is thought to be an important factor in Alzheimer's, a degenerative brain disorder involving profound memory impairment that afflicts between 5-10% dopamine- mediates a wide range of functions, including motivation, reward, and feeling pleasure;voluntary motor control; and control of thought process serotonin- influences mood, eating, sleep and sexual behaviour endorphins- reduce pain and increase feelings of well being |
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what are the 3 types of neurons? what are their functions? |
sensory- carry input messages from sense organs to the spinal chord and brain motor- transmit output impulses from the brain and spinal cord to the boys muscles and organs interneurons- perform connective or associative functions within the nervous system |
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differentiate between the central and peripheral nervous systems. what are the 2 divisions of the peripheral system? |
CNS- consisting of all the neurons in the brain and spinal cord PNS- composed of all the neurons that connect the CNS with the muscles, glands, and sensory receptors somatic and autonomic |
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describe the 2 divisions of the autonomic nervous system , as well as their roles in maintaining homeostasis |
sympathetic- has an activation or arousal function, and it tends to act as a total unit (flight or fight). speeds up heat rate, dilates pupils, slows digestion, increases rate of respiration so your body can get more oxygen to muscles parasympathetic- slows down body processes and maintains or returns you to a state of rest. slows down heart rate, |
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how do spinal reflexes occur? |
can be triggered at the level of the spinal cord without any involvement of the brain. example; you touch something hot and you pull your hand away |
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describe 4 methods used to study brain behaviour relations |
neuropsychological tests- to measure verbal and non-verbal behaviours that are known to be affected by particular types of brain damage. destruction and stimulation techniques- experimental studies are another useful method of learning about the brain electrical recording-because electrodes can record brain activity as well as stimulate it, it is possible to eavesdrop on the electrical conversations occurring within the brain brain imaging- permit neuroscientists to peer into the living brain |
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how are CT scans, PET scans, and MRI's produced and how is each used in brain research? |
CT- a highly focused beam of X-rays takes pictures of narrow slices of the brain. a computer analyzes the X-rayed slices and creates pictures of the brains interior from many different angles PET-measure brain activity, including metabolism, blood flow and neurotransmitter activity based on the fact that glucose is the major nutrient of neurons MRI-creats images based on how atoms in living tissue respond to a magnetic pulse delivered by the device |
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in what sense might the structure of the human brain mirror evolutionary development? |
the structures of the brains core govern the basic physiological functions, such as breathing and heart rate, that keep us alive. |
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which behavioural functions are controlled by the hindbrain structures, namely, the medulla, the pons, and the cerebellum? what occurs with damage to these structures? |
medulla- functions occur automatically such as heart rate and breathing. damage usually results in death. pons- contains motor neurons that control the muscles and glands of the face and the neck. damage can be deadly cerebellum- muscular movement coordination, but also plays a role in certain types of learning and memory |
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describe the roles played by the ascending and descending reticular formation. why is it called the brains gatekeeper? |
ascending- sends input to higher regions of the brain to alert it descending- through which higher brain centres can either admit or block out sensory input |
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what is the role of the thalamus in sensory input, and possibly in thought and perceptual disorders? |
the thalamus is an important sensory relay station, sometimes likened to a switchboard that organizes inputs from sen organs and routes them to the appropriate areas of the brain.the visual, auditory and body senses all have a major relay station in the thalamus |
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what role does the hypothalamus have in motivated behaviour, hunger, pleasure-pain, and hormonal functions? |
hypothalamus plays a major role in controlling many different basic biological drives, including sexual behaviour, temp regulation, eating, drinking, aggression, and the expression of emotion |
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what is the possible relation between hypothalamus and the limbic system regarding emotion and motivation? what roles do the hippocampus and amygdala play in psychological functions? |
the limbic system helps to coordinate behaviours needed to satisfy motivational and emotional urges that arise in the hypothalamus, and it is also involved in memory. hippocampus- is involved in forming memories. amygdala-organizes emotional response patterns, particularly those linked to aggression and fear. |
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what are the 4 lodes pf the brain and where are they located? |
frontal-front parietal-middle temporal-side occipital- back |
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differentiate between sensory, motor, and association cortex, |
motor- which controls the 600 ormolu muscles involved in voluntary body movements, lies at the rear of the frontal lobe adjacent to the central fissure sensory- receives sensory input that gives rise to our sensations of heat, touch, cold, and our sense of balance and body movement association- found within all lobes of the cereal cortex, is critically involved in the highest levels of mental functions, including perception, language and thought |
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where are wernicke's and broca's areas? how are they involved in speech? |
wernicke's area- in the temporal lobe is involved in language comprehension broca's area- in the frontal lobe is necessary for normal speech production. |
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describe the role of the frontal cortex in higher mental functions |
the prefrontal cortex, located just behind the forehead, is the seat of the so-called executive functions. executive functions, mental abilities involving goal setting, judgment, strategic planning and impulse control, allow people to direct their behaviour in an adaptive fashion |
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what is hemispheric lateralization, and what do we know about the functions that are concentrated in the left and right hemispheres? |
lateralization refers to the relatively greater localization of a function in one hemisphere to the other. verbal abilities and speech are localized in the right and mathematical and logical abilities in the left |
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what roles have the corpus callosum and the optic chasm played in split brain research? is it reasonable to speak of separate right and left brains in normal people? |
when the corpus callosum is cut visual input to one hemisphere can be restricted by projecting the stimulus to either the right side of the visual field or the left of the visual field, which sends it to the right hemisphere some of the fibres of the optic nerve from each eye cross over at the optic chasm and travel to the opposite brain hemisphere. fibres that transmit messages from the right side of the visual field project to the left hemisphere and vice versa |
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how is language lateralized in the brain? are there sex differences? |
language tends to be localized in the left hemisphere. males and females may differ in the extent to which certain language functions are lateralized, or located, on one side of the brain. |
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what is neural plasticity? How do age, environment, and behaviour affect plasticity? |
neural plasticity- refers to the ability of neurons to change in structure and function. brain development is programmed by complex commands from our genes, but how these genetic commands express themselves can be powerfully affected by the environment in which we develop, including the environment we are exposed to in the womb |
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why do children typically show better recovery of function after brain injury? |
the 1-2 year old has about 50% more brain synapses than a mature adult. this greater availability of synapses may help to explain why children can recover from brain damage more quickly and completely then adults. |
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reticular formation |
brainstem nerve network that plays an important role in controlling arousal |
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aphasia |
language impairment, usually caused by left hemisphere damage either broca's or wernicke's area |
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endocrine system |
the bodys slow chemical communication system -a set of glands that secrete hormones into the bloodstream |
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hormones |
chemical messengers, mostly those manufactures by the endocrine glands, that are produced in one tissue and affect another |
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adrenal glands |
-a pair of endocrine glands just above the kidneys -secrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stress |
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pituitary gland |
under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands |
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7 steps in neurotransmitter action |
1. N.T.M are synthesized from precursors under the influence of enzymes 2. N.T.M are stored in vesicles 3.N.T.M that leak from their vesicles are destroyed by enzymes 4. Action potentials cause vesicles to fuse with the presynaptic membrane and release their N.T.M into the synapse 5. released N.T.M bind with auto receptors and inhibit subsequent N.T release 6.released N.T.M bind to postsynaptic receptors 7.released N.T.M are deactivated either by uptake or enzymatic degradation |
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agonistic drug effects |
-drugs increase the synthesis of N.T.M -drug increase the number of n.t.m by destroying degrading enzymes -drug increases the release of n.t.m from terminal buttons -drug binds to auto receptors and blocks their inhibitory effect on n.t.m -drug binds to postsynaptic receptors and either activates them or increases the effect on them on n.t.m -drug blocks the deactivation of n.t.m by blocking degradation or reuptake |
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antagonistic drug effect |
-drug blocks the synthesis of n.t.m -drug cases the n.t.m to leak from the vesicle and be destroyed by degrading enzymes -drug blocks the release of the n.t.m from the terminal buttons -drug activates auto receptors and inhibits n.t release -drug is a receptor blocker; it binds to the postsynaptic receptors and blocks the effect of the n.t. |
