BioBasis Test 1
Terms
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- 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 - 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 - 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 - 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 - 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 - Dualism
- Belief that mind and body are different kinds of substance - Both mental and physical substance-That exist independently
- 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 - 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 - 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 - 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 - 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 - 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 - Electrical Gradient
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Difference in electrical charge between inside & outside of cell
-Pulls potassium in - 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 - Depolarization
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Reduction of polarization
-Decrease in negative charge--Moves toward zero
-EPSP
-Positively charged current results in depolarization - Hyperpolarization
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Increased polarization
-Increase negative charge
-Negatively charged current results in hyperpolarization
-IPSP - EPSP
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Excitatory Postsynaptic Potential
-Graded depolarization
-occurs when sodium ion enters the cell--Decays overtime & space-magnitude fades rapidly
-Depolarization - IPSP
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Inhibitory Postsynaptic Potential
-Temporary hyperpolarization
-Occurs when synaptic input selectively opens gates for potassium to leave -
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 -
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 - 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 - 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- - 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 - 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 - Drug mechanisms
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-Agonist-Increase or mimic effects: Full, Partial, Co-Agonist
-Antagonist-Blocks the effects
-Mixed - 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 - 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 - 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 -
Psychostimulants
1)Amphetamines
2)Methamphetamines -
1)stimulate dopamine from presynapse
-blocks receptors that inhibit dopamine release
2)Meth-More potent than amphetamines -
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 -
Psychostimulants
5) Ecstacy -
Methylenedioxymethamphetamine
-Low Doses-dopamine release
-High Doses-Dopamine & Serotonin release
-memory difficulties, psychomotor slowing, mood disturbances
-Thinning of cortical neurons - 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