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Welcome it is a great day to learn about the Brain

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What does the Brain do? Rally Robin with your shoulder partner EVERYTHING your brain does

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We are going to start small and go big

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Neurons: The Building Blocks of the Nervous System

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Nervous System The electrochemical communication system of the body Sends messages from the brain to the body for movement Brings information to the brain from the senses

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Neuron The basic building block of the nervous system -- a nerve cell Neurons perform three basic tasks Receive information Carry the information Pass the information on to the next neuron

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Types of Neurons SensoryMotor Interneuron's

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Spinal Cord Brain Sensory Neuron Sensory Neurons INPUT From sensory organs to the brain and spinal cord Drawing shows a somatic neuron

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Motor Neurons OUTPUT From the brain and spinal cord to the muscles and glands Spinal Cord Brain Sensory Neuron Motor Neuron

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Spinal Cord Brain Sensory Neuron Motor Neuron Interneuron's Interneurons carry information between other neurons only found in the brain and spinal cord

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The Basic Parts of a Neuron

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What are the primary parts of a typical neuron? Nervous system Neurons Dendrites Soma Axon Terminal branches of Axon Myelin Sheath

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The Basic Parts of a Neuron

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Parts of the Neuron

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A. Dendrites Thin, branching fibers lined with receptors at which the dendrite receives information from other neurons.

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Parts of the Neuron - Dendrites

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B. Cell Body/Soma Contains the nucleus and other parts of the cell needed to sustain life

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Parts of the Neuron - Soma

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C. Axon Carries the message across the neuron

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Parts of the Neuron - Axon

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D. Myelin Sheath An insulating, fatty covering around the axon that speeds neural transmissions. Axons that are myelinated appear white. Known as white matter.

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Parts of the Neuron Myelin Sheath

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E. Axon Terminal Buttons The branched end of the axon that contains neurotransmitters

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Parts of the Neuron - Terminals

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Time to Move Locate the person furthest from you Go to that person Introduce yourself

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Stand up, hand up, pair up wait

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Neuron

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Neuron

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Neural Transmission

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Neural Communication: The Neural Impulse

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Action Potential A brief electrical charge that travels down the axon of the neuron. A neural impulse Considered an on condition of the neuron

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Refractory Period The recharging phase when a neuron, after firing, cannot generate another action potential Once the refractory period is complete the neuron can fire again

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Resting Potential The state of a neuron when it is at rest and capable of generating an action potential The neuron is set and ready to fire

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Neuron firing like a Toilet 1. Like a Neuron, a toilet has an action potential. When you flush, an impulse is sent down the sewer pipe

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Neuron firing like a Toilet 2. Like a neuron, a toilet has a refractory period. There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilled

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Neuron firing like a Toilet 3. Like a Neuron, a toilet has a resting potential. The toilet is charged when there is water in the tank and it is capable of being flushed again 4. Like a Neuron, a toilet operates on the all-or-none principle it always flushes with the same intensity, no matter how much force you apply to the handle

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All-or-None Principle The principle that if a neuron fires it will always fire at the same intensity All action potentials are of the same strength. A neuron does NOT fire at 30%, 45% or 90% but at 100% each time it fires.

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Communication Between Neurons Module 7: Neural and Hormonal Systems

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Synapse The space between the terminal buttons on one neuron and dendrites of the next neuron

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Neurotransmitters Chemicals contained in the terminal buttons that enable neurons to communicate. Neurotransmitters fit into receptor sites on the dendrites of neurons like a key fits into a lock.

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Neurotransmitters

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Neurotransmitters A chemical messenger that travels across the synapse from one neuron to the next Can influence whether the second neuron will generate an action potential or not

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Excitatory Effect A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential (impulse) The second neuron is more likely to fire.

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Inhibitory Effect A neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential (impulse) The second neuron is less likely to fire.

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Neurotransmitters

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Acetylcholine (Ach) Found in neuromuscular junctions Involved in muscle movements Involved in learning and memory Involved in REM sleep

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Disruption of Acetylcholine Functioning Nerve gases and Black Widow spider venom too much ACh leads to severe muscle spasms and possible death Cigarettes nicotine works on ACh receptors can artificially stimulate skeletal muscles, leading to slight trembling movements

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Acetylcholine - Alzheimers Disease Deterioration of memory, reasoning, and language skills Symptoms may be due to loss of ACh neurons

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Dopamine Involved in movement, attention, and learning Reward and motivation drugs can impair this greatly

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Dopamine - problems Dopamine imbalance also involved in schizophrenia Loss of dopamine-producing neurons is cause of Parkinsons disease

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Parkinsons Disease Results from loss of dopamine-producing neurons in the substantia nigra Symptoms include difficulty starting and stopping voluntary movements tremors at rest stooped posture rigidity poor balance

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Serotonin Affects mood, hunger, sleep, and arousal Emotional states

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Serotonin Problems Involved in depression Prozac works by keeping serotonin in the synapse longer, giving it more time to exert an effect

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Endorphins Natural opiates that are released in response to pain and vigorous exercise Positive emotions

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Norepinephrine Physical Arousal Fight or flight response Works with the sympathetic nervous system Learning memory

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Norepinephrine Problems: depression and stress

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GABA Muscular movement; inhibition of brain activity

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GABA PROBLEMS: Undersupply linked to seizures, tremors, and insomnia Anxiety disorders

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GABA Huntingtons disease involves loss of neurons in striatum that utilize GABA Symptoms: jerky involuntary movements mental deterioration

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Epinephrine Adrenaline Burst of Energy (small amounts in brain) Works with the endocrine system to ensure lasting energy from threats

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Epinephrine problems Can lead to chronic stress syndrome

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Glutamate Involved in memory

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Glutamate Oversupply can over stimulate the brain, producing migraines or seizures

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Drugs and Chemical Interactions with Neural Transmission

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Prozac blocking the re-uptake of Serotonin

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Neural Communication: The Neural Chain Module 7: Neural and Hormonal Systems

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Receptor Cells Specialized cells in the sensory systems of the body that can turn other kinds of energy into action potentials that the nervous system can process Receptor cells in the eye turn light into a neural impulse the brain understands.

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Sensory Nerves Nerves that carry information to the central nervous system Connect the sense organs to the brain and spinal cord

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Interneuron's Nerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output

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Motor Nerves Nerves that carry information from the central nervous system Carries messages from the brain and spinal cord to other parts of your body

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A Neural Chain

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Most information travels from the body, up the spinal cord, is processed by the brain, sent back down the spinal cord, and then back to the body with behavior instructions. The exception to this general pathway is reflexes.

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Reflexes are controlled by the spinal cord without any conscious effort on behalf of the brain. Reflexes serve as primitive responses that protect our bodies from danger and help us adjust to our surroundings.

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Reflex We cough, for example, when an irritant enters our windpipe and we need to expel it through our mouth. We sneeze when we need to clear our nasal air passages of irritants and allergens. We blink when danger threatens the sensitive tissues of the eye and when we need to moisten and clean the cornea. (This reflex occurs 900 times an hour!) We yawn when nerves in the brain stem find there's too much carbon dioxide in the blood.

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Reflex Spinal Cord

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