Action Potential In The Neuron [AP Psychology Unit 2 Topic 4]

00:10:14
https://www.youtube.com/watch?v=hRyp-dAOAoM

Summary

TLDRIn this video from Mr. Sin's channel, neural firing in AP Psychology is explored, focusing on neurons and neurotransmitters. The nervous system consists of sensory neurons (afferent) which send signals to the brain and motor neurons (efferent) which send signals back to the body. Mirror neurons mimic others' actions, like yawning. Neurons fire by generating action potentials, an all-or-nothing game based on signal intensity. Neurons are polarized, with depolarization sending impulses and repolarization returning them to a resting state. The synapse, a gap between neurons, facilitates signal transmission via chemical neurotransmitters. Various neurotransmitters, such as dopamine and serotonin, influence movement, mood, and other body functions. The video discusses the role of reuptake and how drugs regulate neurotransmitter activity, promising to delve deeper into these mechanisms in a subsequent video.

Takeaways

  • 🔬 Neurons send signals via action potentials and differentiate signals based on frequency.
  • 🤔 Mirror neurons mimic others, explaining contagious actions like yawning.
  • 🚦 Neurons rely on depolarization to fire signals, an all-or-nothing process.
  • 🔗 Synapses connect neurons, enabling chemical and electrical communication.
  • 💊 Neurotransmitters like dopamine affect emotions and movements, impacting disorders.
  • ♻️ Reuptake reabsorbs extra neurotransmitters in the synaptic gap.
  • 🌀 Resting potential keeps neurons polarized, while stimuli trigger depolarization.
  • 🩺 Acetylcholine enables muscle movement, memory, and learning.
  • 📉 Lack of neurotransmitters like serotonin can lead to depression.
  • 🧠 Chemical synapses involve neurotransmitters crossing synaptic clefts to transfer messages.

Timeline

  • 00:00:00 - 00:05:00

    In this segment, Mr. Sin introduces the topic of neural firing in AP Psychology, highlighting the importance of understanding the nervous and endocrine systems discussed in previous videos. He explains the roles of different types of neurons: sensory (afferent), which send information to the brain, motor (efferent), which carry information from the brain, and mirror neurons, which mimic observed actions. He discusses the action potential, the concept of neurons firing impulses, compared to a battery releasing energy. The process involves ion permeability across cell membranes and the movement of positive ions causing depolarization when stimulated, leading to an action potential if the stimulus meets the threshold. Firing is an all-or-nothing process, followed by repolarization and a refractory period, during which neurons cannot respond to stimuli until they return to a resting state.

  • 00:05:00 - 00:10:14

    Mr. Sin continues by explaining how signals propagate after an action potential reaches the axon terminal. The synapse, consisting of parts of two neurons, facilitates this process. He details chemical synapses, where neurotransmitters cross the synaptic gap to transmit information between neurons. Key neurotransmitters include acetylcholine, dopamine, serotonin, endorphins, epinephrine, norepinephrine, glutamate, and GABA, each with specific effects on functions such as muscle movement, mood, alertness, and pain perception. Excitatory neurotransmitters increase the likelihood of action potentials, while inhibitory ones decrease it, with outcomes depending on the balance of types at a synapse. The process includes reuptake, where neurotransmitters are reabsorbed, a mechanism often targeted by drugs. The video concludes with a teaser for the next topic on drugs influencing neurotransmitter activity.

Mind Map

Video Q&A

  • What is the role of sensory neurons?

    Sensory neurons, also known as afferent neurons, receive signals from sensory receptors and send them to the brain and spinal cord.

  • What are mirror neurons responsible for?

    Mirror neurons mimic the actions of others, which is why seeing someone yawn might make you yawn as well.

  • How do neurons send signals?

    Neurons send signals through an action potential, which is an impulse that travels down the axon. The frequency of these impulses helps differentiate signals.

  • What starts an action potential in a neuron?

    An action potential starts when a neuron is sufficiently stimulated by an outside stimulus, leading to depolarization and a neural impulse.

  • What happens during the refractory period?

    During the refractory period, a neuron cannot respond to another stimulus until it is reset to resting potential through repolarization.

  • What is the role of neurotransmitters?

    Neurotransmitters are chemical messengers that cross the synaptic gap to transmit signals from one neuron to another.

  • What is the difference between electrical and chemical synapses?

    Electrical synapses transmit information quickly without a gap, while chemical synapses involve a synaptic gap and involve neurotransmitters.

  • What effects can dopamine have on the body?

    Dopamine is involved in movement, learning, attention, and emotion. An imbalance can lead to conditions like schizophrenia or Parkinson’s disease.

  • What happens during reuptake?

    During reuptake, excess neurotransmitters left in the synaptic gap are reabsorbed by the presynaptic neuron.

  • How can drugs affect neurotransmitter activity?

    Drugs can influence the production, release, and reuptake of neurotransmitters, leading to various effects on the body.

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  • 00:00:00
    hello there everyone and welcome back to
  • 00:00:01
    the mr sin channel today we are going
  • 00:00:03
    into unit 2 topic 4 of ap psychology
  • 00:00:06
    neural firing now if you haven't watched
  • 00:00:08
    my last two videos pause this video and
  • 00:00:10
    go check out my video on the endocrine
  • 00:00:12
    system and also the nervous system those
  • 00:00:14
    videos will be important for you to
  • 00:00:15
    understand everything that's going to be
  • 00:00:17
    in this video all right so by now you
  • 00:00:18
    know that the nervous system is pretty
  • 00:00:20
    complex and it's made up of a bunch of
  • 00:00:22
    different parts each part has its own
  • 00:00:23
    specific function that allow us to be us
  • 00:00:26
    remember our nervous system is made up
  • 00:00:27
    of different neurons we have sensory
  • 00:00:29
    neurons also known as afferent neurons
  • 00:00:31
    these neurons receive information and
  • 00:00:33
    signals from our sensory receptors and
  • 00:00:35
    they send that information up to our
  • 00:00:37
    brain and spinal cord make sure you
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    remember these neurons send information
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    to the brain and spinal cord the two is
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    important there once the brain gets that
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    information it processes that
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    information and then it sends the
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    information back to the body through the
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    motor neurons also known as the efferent
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    neuron these allow information to travel
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    from our brain to the rest of the body
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    one way you can remember this is
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    afferent approaches the brain and
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    efferent exits the brain a for approach
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    and e for exit we also have mirror
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    neurons these neurons are why when
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    someone yawns you might start to yawn
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    these neurons mimic they react to the
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    actions of another or our cell now in
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    order for neurons to send a message they
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    need to receive enough stimulation to
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    cause an action potential neurons can
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    only send one signal at a time and can
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    only be sent at a set speed and strength
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    now you might be asking well how can the
  • 00:01:23
    signals then be distinguished well it's
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    all about the frequency neurons can
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    change the number of signals depending
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    on the rate in which they're being sent
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    your brain is able to understand the
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    differences in the frequency and process
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    the signals sent by the neuron when a
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    neuron sends a message the physiological
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    process is known as an action potential
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    this is when a neuron fires an impulse
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    down the axon now i can already hear
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    some of you asking how does all this
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    happen what can cause neurons to fire
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    these electrical impulses well think
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    about your neuron like a battery for
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    example this battery right here that i'm
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    holding has both a positive end and a
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    negative end right now this battery has
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    the potential to release energy but it
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    can't do that unless there's a
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    connection made between the two ends a
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    neuron is similar you have in your body
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    positively charged and negatively
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    charged ions your cell membranes
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    separate the ions and creates an
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    environment on either side of the
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    barrier that is overall positive or
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    overall negative this gives your neurons
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    potential some ions are able to cross
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    the membrane more easily than others
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    which is known as permeability think
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    about it like having a ticket to a
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    concert if you don't have a ticket you
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    can't get into the venue certain ions
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    have characteristics that'll allow them
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    to pass more easily through the neurons
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    membrane when a neuron is not sending a
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    signal it has more negative ions in the
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    inside than on the outside and that's
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    called a resting potential when a neuron
  • 00:02:38
    is resting there are a lot of positive
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    ions outside the membrane waiting to
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    enter neurons in a state of rest are
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    polarized and in order for them to send
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    a signal an action potential the process
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    of depolarization must occur for a
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    neuron to depolarize there has to be an
  • 00:02:51
    outside stimulus let's say all of a
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    sudden a plate falls on your foot this
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    would stimulate sensory afferent neurons
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    this would cause ion channels along the
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    cell membrane of the neuron to open
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    letting more positive ions inside this
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    increases the positive charge inside the
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    membrane which triggers the action
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    potential now not all stimuli to a
  • 00:03:08
    neuron causes an action potential there
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    has to be enough positive ions let in if
  • 00:03:12
    there are enough where the resulting
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    change is strong enough to meet the
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    threshold the depolarization occurs and
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    the neuron fires an action potential if
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    it does not meet the threshold there is
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    no firing and there will be no action
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    potential and the neuron will return to
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    a resting state this is important to
  • 00:03:27
    remember that neurons act in kind of an
  • 00:03:29
    all or nothing game when an action
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    potential occurs it sends a signal down
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    the axon to the other neurons in the
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    nervous system after one neuron goes
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    through an action potential and goes
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    through the process of depolarization
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    the process of repolarization occurs in
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    order to bring the neuron back to
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    resting potential during this
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    repolarization process different ion
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    channels open back up to try and
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    rebalance the charges by letting more
  • 00:03:50
    positive ions outside of the cell
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    membrane when all of this is happening
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    and the signal is moving down the axon
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    the neuron cannot respond to any other
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    stimulus this is known as the refractory
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    period when this happens the neuron
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    needs another stimulus in order to meet
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    the threshold or intensity level to be
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    able to fire again now all right so all
  • 00:04:08
    this is great and all but i can already
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    hear some of you asking well what
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    happens after a signal is shot down the
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    axon how does the signal or action
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    potential connect from one neuron to
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    another neuron and to answer that we
  • 00:04:18
    need to look at the synapse which is
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    composed of parts of two different
  • 00:04:21
    neurons remember the neuron is made up
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    of dendrites the cell body the axon the
  • 00:04:25
    axon terminal once the action potential
  • 00:04:27
    has occurred the message has been sent
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    through the axon until it reaches the
  • 00:04:31
    end of the neuron called the axon
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    terminal in the last video we talked
  • 00:04:35
    about the process of an action potential
  • 00:04:36
    reaching the axon terminal and that
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    neurotransmitters were released into the
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    space between the two neurons to further
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    send the information this space is where
  • 00:04:44
    the signal is converted and sent to
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    another neuron now there are electrical
  • 00:04:48
    synapses and chemical synapses
  • 00:04:50
    electrical synapses are for messages
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    that need to be sent quickly and
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    immediately they are connected and have
  • 00:04:55
    no space between neurons chemical
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    synapses on the other hand take longer
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    to process most of the interactions
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    we're talking about are going to be
  • 00:05:02
    chemical synapses chemical synapses use
  • 00:05:05
    neurotransmitters which are chemical
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    messengers that are diffused across the
  • 00:05:08
    synaptic gap to deliver their messages
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    the synaptic gap is also known as the
  • 00:05:12
    synaptic cleft it's a narrow space
  • 00:05:14
    between the neurons specifically the
  • 00:05:16
    presynaptic terminal of one neuron and
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    the postsynaptic terminal of the next
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    neuron it's easy to remember if you
  • 00:05:21
    break down the word pre before the
  • 00:05:23
    synapse and post after the synapse the
  • 00:05:26
    presynaptic terminal is the axon
  • 00:05:28
    terminal of the neuron which converts
  • 00:05:30
    the electrical signal to a chemical one
  • 00:05:32
    and sends the neurotransmitters into the
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    synaptic gap the postsynaptic terminal
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    is where the neurotransmitters are
  • 00:05:38
    accepted in the dendrites the receptor
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    region of the receiving neuron remember
  • 00:05:42
    from our last video the dendrites extend
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    outward from the soma and have receptors
  • 00:05:46
    at the end of them this allows them to
  • 00:05:48
    be able to receive messages from
  • 00:05:50
    previous neurons now since i mentioned
  • 00:05:51
    neurotransmitters there are lots of
  • 00:05:53
    different types that do different things
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    i want to highlight the different types
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    of neurotransmitters our bodies use
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    before continuing with how neurons send
  • 00:06:00
    signals and messages up first we have
  • 00:06:02
    acetylcholine which enables muscle
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    action learning and memory when you are
  • 00:06:06
    moving around your body is firing off
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    acetylcholine if your body is not making
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    enough acetylcholine you become at risk
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    for diseases such as alzheimer's next is
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    dopamine it helps with our movement
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    learning attention and emotion it's
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    often referenced as a natural drug
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    because of how it impacts your feelings
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    and emotion if your body has too much
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    dopamine you are at risk for
  • 00:06:25
    schizophrenia and an under supply could
  • 00:06:27
    lead you to develop a decrease in your
  • 00:06:29
    mobility and possibly parkinson's
  • 00:06:31
    disease serotonin impacts your hunger
  • 00:06:33
    sleep arousal and mood if your body does
  • 00:06:36
    not produce enough serotonin you are at
  • 00:06:37
    risk for depression if you have too much
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    serotonin you might experience obsessive
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    compulsive disorder anxiety or headaches
  • 00:06:43
    this is often known as the feel good
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    chemical up next is endorphins which
  • 00:06:47
    help with pain control this is like your
  • 00:06:48
    body is producing its own morphine if
  • 00:06:50
    you're lacking endorphins you'll have a
  • 00:06:52
    lower pain threshold if you have an
  • 00:06:54
    excess you will have a higher pain
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    threshold also if you remember from the
  • 00:06:57
    2.2 topic review video epinephrine or
  • 00:06:59
    adrenaline and norepinephrine are also
  • 00:07:02
    significant hormones and
  • 00:07:03
    neurotransmitters in the body they both
  • 00:07:05
    work together on the body's fight or
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    flight response that will increase your
  • 00:07:08
    heart rate expand the air passages of
  • 00:07:10
    the lungs and redistributes blood to
  • 00:07:12
    muscles you could say that they help
  • 00:07:14
    with your alertness and arousal the last
  • 00:07:16
    two types of neurotransmitters we're
  • 00:07:17
    going to be talking about is glutamate
  • 00:07:19
    and gaba glutamate is involved with
  • 00:07:20
    excitatory messages it helps us with
  • 00:07:22
    long-term memory and learning it is used
  • 00:07:24
    more by neurons than any other
  • 00:07:26
    neurotransmitter if you have an excess
  • 00:07:28
    amount it might over overstimulate the
  • 00:07:29
    brain which could create seizures
  • 00:07:31
    insomnia or give you a migraine gaba
  • 00:07:33
    helps us with sleep and movement it
  • 00:07:35
    slows down your nervous system if you do
  • 00:07:37
    not have enough gaba this might lead to
  • 00:07:39
    seizures tremors or insomnia so you can
  • 00:07:41
    see that each neurotransmitter helps
  • 00:07:43
    communicate different messages and has
  • 00:07:45
    different impacts on our body remember
  • 00:07:47
    the nervous system sends a chemical
  • 00:07:49
    signal through neurotransmitters the
  • 00:07:51
    neuron sends these neurotransmitters
  • 00:07:53
    across the synaptic gap also known as
  • 00:07:55
    the synaptic clef and again this is the
  • 00:07:57
    narrow space between the presynaptic
  • 00:07:59
    terminal and the postsynaptic terminal
  • 00:08:00
    now depending on which neurotransmitter
  • 00:08:02
    binds to the receptor we might see the
  • 00:08:04
    neuron get excited or inhibited
  • 00:08:06
    excitatory neurotransmitters will
  • 00:08:07
    increase the likelihood that a neuron
  • 00:08:09
    will fire an action potential through
  • 00:08:10
    the depolarization process in the
  • 00:08:12
    postsynaptic neuron this is because the
  • 00:08:14
    inside of the neuron will become more
  • 00:08:16
    positive and will push the neuron
  • 00:08:17
    towards the intensity or threshold
  • 00:08:19
    needed for it to have an action
  • 00:08:20
    potential on the other hand an
  • 00:08:21
    inhibitory neurotransmitter will
  • 00:08:23
    decrease the likelihood that a neuron
  • 00:08:24
    will fire an action potential this leads
  • 00:08:26
    to hyperpolarization to occur which is
  • 00:08:28
    when the inside of the neuron becomes
  • 00:08:30
    more negative which moves farther away
  • 00:08:32
    from its threshold or intensity needed
  • 00:08:34
    for an action potential each part of a
  • 00:08:36
    neuron could have hundreds of synapses
  • 00:08:38
    and each of those synapses has different
  • 00:08:40
    inhibitory and excitatory
  • 00:08:41
    neurotransmitters so the odds of a
  • 00:08:43
    postsynaptic neuron experience an action
  • 00:08:45
    potential depend on the sum of all
  • 00:08:47
    excitatory neurotransmitters and
  • 00:08:49
    inhibitory neurotransmitters in the area
  • 00:08:51
    once the neurotransmitters have passed
  • 00:08:52
    their messages onto the postsynaptic
  • 00:08:54
    neuron they unbind with the receptors
  • 00:08:56
    some of the neurotransmitters are
  • 00:08:58
    destroyed and others get reabsorbed this
  • 00:09:00
    process of taking excess
  • 00:09:02
    neurotransmitters left in the synaptic
  • 00:09:04
    gap is known as reuptake this is when
  • 00:09:05
    the sending neuron at the presynaptic
  • 00:09:07
    terminal reabsorbs the extra
  • 00:09:09
    neurotransmitter in our next video we'll
  • 00:09:10
    be talking more about the release and
  • 00:09:12
    reabsorption of neurotransmitters as
  • 00:09:15
    this is where many legal and also
  • 00:09:16
    illegal drugs exploit when exciting the
  • 00:09:18
    production release and reuptake of
  • 00:09:19
    neurotransmitters or inhibiting it drugs
  • 00:09:21
    can elicit different effects on our body
  • 00:09:23
    but all of that is for the next video
  • 00:09:25
    don't forget now to answer the questions
  • 00:09:27
    on the screen and check your answers in
  • 00:09:28
    the comments section below also if you
  • 00:09:30
    need more help with ap psychology make
  • 00:09:31
    sure to check out my ultimate review
  • 00:09:33
    packet it has summary videos for all of
  • 00:09:35
    the different topics in ap psychology it
  • 00:09:38
    also has study guides answer keys
  • 00:09:39
    practice quizzes and more i've included
  • 00:09:41
    different documents to help you with
  • 00:09:43
    unit 2 as well that look at the neuron
  • 00:09:45
    the nervous system and also the brain
  • 00:09:47
    hopefully this will help you get an a in
  • 00:09:48
    your class and also a five on the
  • 00:09:50
    national exam all right i'm mr sin thank
  • 00:09:51
    you so much for watching today and as
  • 00:09:53
    always i'll see you next time online
  • 00:10:14
    you
Tags
  • neural firing
  • neurotransmitters
  • neurons
  • action potential
  • synapse
  • AP Psychology
  • nervous system
  • neurobiology
  • reuptake
  • neural transmission