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32 Cards in this Set
- Front
- Back
Glial Cells
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Does not conduct impulses to other cells-Don't transport info
- About 90% found in brain -Provide repair, support, & protection for neurons -Can regenerate as needed -Other major cellular component of nervous system -Exchange chemicals with adjacent neurons -Majority found in CNS |
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6 Types of Glial Cells
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1)Oligodendrocytes-Extensions wrap around axon of some neurons in CNS-Brain & Spinal cord
2)Schwann Cells-Extensions wrap around axon of neurons in PNS-Build myelin sheath 3)Microglia-Smallest-Trigger inflammatory response-Clean debris 4)Astrocytes-Largest-Help remove waste material-Wrap around presynaptic terminals-Synchronize axon activity-Pass chemicals back and forth between neurons & blood-Help control amount of blood to brain area-Part of blood brain barrier 5)Ependymal-Line the central canal of the spinal cord or ventricles of the brain 6)Satellite-Help regrowth of muscle fibers |
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Neurons
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Receive info & transmit it to other cells
1)Sensory Neurons (Afferent)- Highly sensitive to particular type of stimulation (touch)-Bring info into a structure towards CNS--Unipolar neuron 2)Motor Neurons (Efferent)- Soma in the spinal cord-Receives excitation from other neurons through dendrites & conducts impulses along axon to muscle--Carries info aware from CNS to muscles--Multipolar neuron |
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Interneurons
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Integrate activity within a brain structure
-Cells dendrites are entirely contained within a single structure & axon -Intrinsic Neuron -Only communicates with other cells -Only found in the CNS |
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Neuron Anatomy
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-Dendrites-Branching fibers carry nerve impulses to cell body
-dendritic spines increase surface area--Important role in long term neuron changes & learning & memory Cell Body- -Nucleus-contains DNA-Genes & DNA control function of neuron -Axon-Long narrow fibers that carry impulses away from cell -Terminal Bouton- (presynaptic terminal)-Releases chemicals to cross to next neuron -Myelin Sheath-Fatty tissue around axon-Adds speed to impulse conduction-helps prevent electrical current from leaving axon |
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Dualism
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Belief that mind and body are different kinds of substance - Both mental and physical substance-That exist independently
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Genes
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Units of heredity that maintain their structural identity from 1 generation to another
-Alleles-2 genes per trait -Aligned along chromosomes -DNA & RNA--DNA is template for RNA which synthesizes proteins -Genes increase the probability of a given behavior directly or indirectly -Directly-Increase probability for alcoholism or maladaptive behaviors -Indirectly-Modify environment to increase probability of behavior |
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Dominant vs. Recessive Genes
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Dominant-Strong effect in either homozygous or heterozygous-prominent in women
Recessive-Effect only in homozygous-prominent in men |
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Sex-Limited Genes
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-Present in both sexes but have effects mainly or exclusively for 1 sex
-Activated by sex hormones and makes its effects evident in 1 sex or the other -Exerts its effects primarily in 1 sex because of activation by androgens or estrogens--Though both sexes have the gene |
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Mutation
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Change in a single gene
-Rare and random -Source of variation Disadvantageous-Mutation leading to altered protein Neutral/Advantage-Mutation that modifies the amount or timing of protein production |
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Sodium-Potassium Pump
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Transports 3 sodium out while drawing 2 potassium in-Active transport--Uses 40% cells energy
-Relies on selective permeability so sodium cannot leak back in -Potassium pumped in may leak out due to concentration gradient, may leak in due to electrical gradient -Sodium sneaks in due to both -Helps maintain concentration |
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Concentration Gradient
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Difference in distribution of ions across the membrane
-Sodium is more concentrated outside so more likely to enter the cell due to concentration and electrical gradient -Potassium sneaks out due to concentration gradient, sneaks in due to electrical gradient |
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Electrical Gradient
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Difference in electrical charge between inside & outside of cell
-Pulls potassium in |
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Resting Potential
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Electrical potential across a membrane when a neuron is not being stimulated
-Difference in voltage in a resting neuron-Result of negatively charged proteins inside cell -Neuron in membrane has slight negative potential compared to the outside -Polarization-difference in electrical charge between 2 locations -Sodium=decrease resting potential -Potassium=raising resting potential |
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Depolarization
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Reduction of polarization
-Decrease in negative charge--Moves toward zero -EPSP -Positively charged current results in depolarization |
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Hyperpolarization
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Increased polarization
-Increase negative charge -Negatively charged current results in hyperpolarization -IPSP |
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EPSP
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Excitatory Postsynaptic Potential
-Graded depolarization -occurs when sodium ion enters the cell--Decays overtime & space-magnitude fades rapidly -Depolarization |
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IPSP
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Inhibitory Postsynaptic Potential
-Temporary hyperpolarization -Occurs when synaptic input selectively opens gates for potassium to leave |
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Types of Receptors
#1 |
1)Ionotropic-Neurotransmitter binding results in direct opening of specific ion channel--Open quick, shut quick
-Excitatory synapses use glutamate -Inhibitory synapses use GABA |
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Types of Receptors
#2 |
2)Metabotropic-NT binding initiates a sequence of internal molecular events which in turn open specific ion channels
-Slow but long lasting effect through metabolic reactions -longer lasting -Use wide variety of NT's |
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Autoreceptors
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Presynaptic receptor that is stimulated by the neurotransmitter released by the presynatpic cell itself, feeding back to decrease further release of the transmitter
-Bind to own neuron -monitor # of NT's in synapse |
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Dopamine
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-Only in central nervous system
-Brain pathways in midbrain -Excitatory or Inhibitory Involved in: Coordinated movement, Reward/Reinforcement -Schizophrenia Dopamine Theory- -Parkinson's Disease-loss of dopaminergic nuclei in substantia nigra -Drug Addiction- |
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Norepinephrine
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Peripheral Nervous System--Fight/Flight Response
Central Nervous System-Arousal, Sustained & Selective Attention--dysregulation of NE networks ADHD- Can function as a hormone when released into the blood |
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Serotonin
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Peripheral nervous system--Cardiovascular regulation, smooth muscle contraction, gastrointestinal functions
Central nervous system--no specific brain structures-sleep-wake cycle Major depressive disorder-Low serotonin (5-HT) activity |
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Drug mechanisms
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-Agonist-Increase or mimic effects: Full, Partial, Co-Agonist
-Antagonist-Blocks the effects -Mixed |
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Nicotine
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-Stimulates ionotropic receptor- Nicotinic Receptor
-increases dopamine in synapses -stimulates epinephrine release -Inhibits monoamine oxidase stimulates release of endorphins -Constant use results in cells becoming less sensitive--cells become dependent on nicotine -Nucleus Accumbens cells (responsible for recinforcement) become less responsive |
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Caffeine
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-Antagonist blocks Adenosine receptors
-increases dopamine -by blocking Adenosine receptors indirectly causes vasodilation, increased renal blood flow & filtration rate, results in release of NE/E -increases serotonin levels -increases endorphines--Inhibits enzyme breaking down 2nd messenger designed to stimulate endorphins -Constricts blood vessels to the brain & prevents adenosine from inhibiting release of dopamine & acetylcholine |
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Psychostimulants
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Elevate dopamine-Increase excitement, alertness & motor activity, elevate mood, decrease fatigue
About 5 types 1)Amphetamines 2)Cocaine 3)Ritalin 4)Meth 5)Ecstacy |
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Psychostimulants
1)Amphetamines 2)Methamphetamines |
1)stimulate dopamine from presynapse
-blocks receptors that inhibit dopamine release 2)Meth-More potent than amphetamines |
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Psychostimulants
3)Cocaine 4)Ritalin |
3)Cocaine-blocks reuptake of dopamine, norepinephrine, & serotonin into presynapse
4)Ritalin(Methylphenidate)- Slower breakdown & 1/2 life than cocaine |
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Psychostimulants
5) Ecstacy |
Methylenedioxymethamphetamine
-Low Doses-dopamine release -High Doses-Dopamine & Serotonin release -memory difficulties, psychomotor slowing, mood disturbances -Thinning of cortical neurons |
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Opiates
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Reduce moderate to dull pain
-mental dullness, delirium, respiratory rate decreases, nausea, constipation Types: Opium, morphine, heroin, methadone 2 Mechanisms 1. Opiates act as endorphins 2. Influences dopamine -presynaptic membrane-inhibit GABA & NE from locus coeruleus -postsynaptic membrane-hyperpolarize the membrane & potassium flows out |