E.4 presentation


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  • Membrane potential (mV)Action potential (AP)
  • Neurotransmitter (NT)
  • Euphoria – extreme happiness
  • Cholinergic Synapses: synapses that have acetylcholine as a transmitter
  • Adrenergic synapse: Synapses where noradrenaline is the neurotransmitter
  • canada
  • second
  • cocaine
  • 14 years
  • E.4 presentation

    1. 1. E.4 Neurotransmitters and Synapses Narisa and Pauline
    2. 2. Synaptic transmission*note that neurotransmitters is received by a receptor but does not enter the postsynaptic neuron
    3. 3. Neurotransmitters (NT) Excitatory Inhibitory •(+) ions to move out of•Increase permeability of the postsynaptic cellpostsynaptic membraneto (+) ions •Depresses postsynaptic cell  harder to excite
    4. 4. Excitatory neurotransmitters• Ex: Achetylcholine (Ach)• Generates action potential• Increase permeability of postsynaptic membrane to (+) ions• Influx of Na+• Depolarization• Action potential
    5. 5. Inhibitory neurotransmitters• Ex: Gamma-aminobutryic acid (GABA)• Hyperpolarization• Postsynaptic neuron more (-)• Cl- in or K+ out• Difficult to generate action potential
    6. 6. Decision-making in the CNS• axons (many neurons) feed into the dendrite of the postsynaptic neuron• Each contribute to the mV of the postsynaptic neuron• excitatory/inhibitory• Summative effect (added up at the axon hillock)• If summative effect of the inputs reaches threshold, an AP is generated
    7. 7. Psychoactive drugs Brain Personality
    8. 8. Cholinergic synapses• Ex of NT: acetylcholine (Ach)  Released by motor neurons  Activates skeletal muscle• Remaining Ach in synapse  Fire indefinitely• Acetylcholinesterase  Breaks down Ach• Parasympathetic nervous system (E.5)  Causes relaxation
    9. 9. Cholinergic synapses (continued)• Cholinergic synapses are synapses that use Ach• Ex: Nicotine  Stimulates transmission in cholinergic synapses  Calming effect
    10. 10. Adrenergic synapses• Ex of NT: noradrenaline  Depolarizes postsynaptic neuron  Sympathetic system  ‘fight or flight’• Synapses using noradrenaline are adrenergic synapses• Ex: Cocaine&amphetamines  Alertness, energy, euphoria
    11. 11. Cholinergic AdrenergicNeurotransmitter Acetylcholine NoradrenalineNervous system Parasympathetic Sympathetic calming Increase energy and Effect on mood alertness, euphoria Drug(s) Nicotine Cocaine, amphet amines
    12. 12. Drugs on synaptic transmission*drugs have structures similar to neurotransmitters*same chemical structure = same effect*not broken down = stays longer = effect stronger http://i-biology.net/options/option-e-neurobiology-and-behaviour/e4-neurotransmitters-and-synapses/
    13. 13. ADDICTION- Tobacco products- Stimulant- Mimics Acetylcholine (Ach)*Cholinergic Synapses (Body & Brain)*Calming Effect
    14. 14. • Ach Case: Ach received by receptors Broken down by acetylcholinesterase• Nicotine Case: Nicotine received by receptors Nicotine molecules remains on the receptors*Excites postsynaptic neuron*release a molecule called dopamine• Dopamine: feeling of pleasure• ‘reward pathway’ of your brain
    15. 15. Cocaine- Adrenergic Synapse ADDICTION- Cocoa plants- Alertness + Euphoria- Dopamine Release Blocks removal of Dopamine from the synapse  Build up of Dopamine Overstimulation of the postsynaptic neuron ‘reward pathway’  Euphoria
    16. 16. http://www.thirteen.org/closetohome/animation/coca-anim-main.html
    17. 17. - Adrenergic synapses- increased energy + alertness*Directly into nerve cells whichcarry dopamine + noradrenaline*Moves into vesicle of presynapticneuron*triggers increase in release ofneurotransmitters: more actionpotentials*Amphetamine interfere withbreakdown
    18. 18. • High concentrations of dopamine  euphoria• High concentrations of noradrenaline  alertness• Amphetamines  high energy
    19. 19. Excitatory Drugs Dopamine Neurotransmitter for CNS Role: way the brain controls movement, memory, decision making More dopamine means: causes neuron to fire more often resulting in a euphoric feeling Excess Contribute to psychotic illnesses (schizophrenia) Underproduction Movement disorder (Parkinson’s) http://outreach.mcb.harvard.edu/animations/synapse.swfhttp://www.psych.ualberta.ca/~ITL/flash/stimulants_draft.swf
    20. 20. Inhibitory DrugsBenzodiazepine• Reduces anxiety• Used against epileptic seizures (brain disorder)• modulate activity of GABA (inhibitory NT) Inhibitory NT  hyperpolarization• Increases the binding of GABA to receptors Postsynaptic neuron  more hyperpolarized
    21. 21. Effect of benzodiazepines at the synapse
    22. 22. Inhibitory DrugsAlcohol• Increases the binding of GABA to the postsynaptic membrane Hyperpolarized• Sedative effect Decrease activity of glutamate (excitatory NT) Increase the release of dopamine
    23. 23. Inhibitory Drugs• Tetrahydrocannabinol (THC)• Psychoactive chemical in marijuana• Mimics NT anandamide  Binds to the same receptor (cannabinoid receptors)• Inhibitory neurotransmitter  Hyperpolarized• Anandamide – role in memory functions  Marijuana affects short-term memory  Anandamide may be involved in eliminating information that is not needed
    24. 24. THC and Cocaine: Mood, synapse, behaviorMarijuanaRelaxed, MellowLight-headed, HazyTHC  Dilate pupils  Color PerceptionSenses may be enhancedPanic + Paranoia SYNAPSE *Cannabinoid receptors Learning Coordination Problem solving Short-term Memory
    25. 25. THC and Cocaine: Mood, synapse, behaviorMechanism*mimics anandamide*inhibits the neurons that anandamide inhibits*No enzyme to break down THC*Stays in the synapse longer = greater effect Coordination Motor impairment (THC) Short Term Memory
    26. 26. THC and Cocaine: Mood, synapse, behaviorCocaineEuphoriaTalkativenessMental AlertnessTemporary decrease in need for food + sleepLarge amounts: erratic/violent behavior SYNAPSE *ability to sustain dopamine levels in the synapse *dopamine: ‘reward pathway’ Longer it is there, the better you feel
    27. 27. Causes of Addiction• Alcohol• Tobacco• Psychoactive drugs• Pharmaceuticals (some)Body: develops a toleranceAddiction: Chemical dependency on drugs where the drug has ‘rewired’ the brain and has become an essential biochemical in the bodySmokingCauses the brain to be rewiredNicotine  mimics acetylcholinePeople who smoke: crave a dopamine spike
    28. 28. Causes of AddictionAddictionAbused drugs: euphoriaWithdrawal: anxiety, depression, cravingAlcohol: seizures, delirium tremens (severe shaking)Continued addiction: harmfulInhaled drugs: damage lungsSharing needles: contract HIV/Hepatitis B and CKidney disease
    29. 29. Genetic Predisposition*Addiction + Genes • Some people are genetically more pre-disposed to becoming addicts • Family histories/pedigree charts  Susceptibility to addiction • Different allele of a receptor gene, or to carry modified versions of other genes linked to drug metabolism • Risk-taking behavior  more likely to experiment with drugs • Explains why some people never try drugs • Why some people who do drugs don’t become addicts Dopamine Receptors Deficiency of dopamine receptors  addiction Case: Rats Alcohol preferring rats  20 % lower levels of dopamine receptors Consumed: 5g ethanol/kg EVEN when given a choice between ethanol + water Non-preferring rats: 1g ethanol/kg of body weight
    30. 30. Social FactorsDetermine child’s vulnerability to substance abuse Family addiction Family parenting skills Mental health problems of family/childPEER PRESSURE!*affects adolescents more than adults*drugs/alcohol*users teach new users: effects to expect + what altered state is desirable
    31. 31. Social FactorsBritish: Opium into ChinaSOCIAL PROBLEMHeroin  USASOCIAL CATASTROPHEAlcohol at parties:Notion that only with alcohol can there be a partySaudi Arabia:Alcohol is prohibited by culture+ lawAlcoholism is rareCHEAP and EASY ACCESS  ADDICTION
    32. 32. Dopamine SecretionDOPAMINE:Neurotransmitter  activate reward pathway  pleasure/satisfactionCocaine use: dopamine build upDrug AddictionReceptors are constantly stimulatedOverstimulation  decreases the number of receptorsLess sensitive  tolerantNeuroadaptive change  critical for producing addiction
    33. 33. Dopamine SecretionResearchKnockout mice – genetically manipulated mice addicted to cocaineNeurotransmitter  GlutamateGlutamate = oversee learning and memories which lead to cocaine seeking
    34. 34. Which was the first country in the world, in 2003, to offer medical marijuana?a) Germanyb) Netherlandsc) Canadad) United States
    35. 35. Cocaine is the _______ most commonly used illicit drug in the United States.a) Firstb) Secondc) Thirdd) Fourth
    36. 36. What did the drink Coca-Cola originally contain?
    37. 37. Scientist claim that the average smoker will lose _____ years of 14 their life due to smoking.
    38. 38. 10Nicotine reaches the brain in _____ seconds.