Biological Basis How the brain impacts our behavior
Biological Basis How the brain impacts our behavior.
Aim: How does the process of neural transmission occur in the nervous system? DO NOW: What happens when you stub your toe? What causes it to occur? Describe the reaction within the nervous system. How are messages sensed, received, and processed? HOMEWORK: • None
If you stub your toe…. . 1. Sensory neurons in toe are activated and send message to brain (via the base of the spine) 2. Sensory Cortex Central Nervous System • Brain 3. Motor Cortex • Spinal Cord 4. Muscles Peripheral Nervous System (afferent and efferent neurons) • Somatic Nervous System • Autonomic Nervous System • Sympathetic Nervous System • Parasympathetic
Types of Neurons • Efferent (Motor) Neurons • Interneurons • Afferent (Sensory) Neurons
The Nervous System • Central Nervous System – Brain – Spinal Cord • Peripheral Nervous System (afferent and efferent neurons) – Somatic Nervous System – Autonomic Nervous System • Sympathetic Nervous System • Parasympathetic
Neuron (nerve cells – transmits info within the nervous system) • Label each part of the neuron page 3 • Complete Analogies • Define terms and connect to toilet flushing.
Neuroanatomy Synapse Neurotransmitters (chemicals held in terminal buttons that travel through synaptic gap) Synapse
SYNAPSE
Parts of a Neuron • 1. Dendrite: “ little tree” “the catcher” Acts like an antenna and receives info from other neurons and transmits it to the cell body. • 2. Cell body/Soma: sphere or pyramid shape – contains nucleus and other parts of cell needed to keep it alive
• 3. Axon: “The batter” Transmits messages away from the cell body • 4. Myelin Sheath: fatty material that insulates the axon. Prevents signals from crossing , increases conduction of impulses
• 5. Terminal Buttons (axon terminals): at end of axon, makes connections to many other neurons • 6. SNYAPSE: area between neurons, neurotransmitters are released into this area
How does a Neuron fire? • Neural Firing is an Electrochemical process • neurotransmitters are released into synapse • if enough neurotransmitters are received + ions rush through cell • the change in charge / electric message = action potential (120 meters per sec. )
• A neuron is at resting potential when the inside of the neuron is more negatively charged on the inside the axon than outside the axon – we also say the neuron is polarized at resting potential = polarized
• the positively charged sodium ions rush in causing the cell to become depolarized • This change in charge of the cell causes an impulse travels down the axon – action potential ( brief change in electrical voltage that) • The action potential flows down the axon to the end of the neuron - direction
• After action potential is achieved the potassium ions flow out of the axon – ( pushing out of the Na, K ions ) – this process is called repolarization
• The time period during which a neuron can not fire again until it “resets” - refractory period (from depolarization, action potential and repolarize it can’t fire)
Analogy : Relate the terms on p. 5 to the flushing of a toilet • • Action potential Resting potential Polarization Depolarization All or None Repolarization Refractory Period http: //brainu. org/files/movies/action_potential_cartoon. swf
Relate the following to our demo. 1. When a cell is at resting potential it is polarized. 2. When the cell becomes depolarized it reaches action potential. 3. The all or none process happens throughout the entire neuron. 4. During the refractory period a neuron repolarizes.
Page 7 of packet Label (# 1 – 5) the firing of a neuron… – Action potential – Repolarization – Resting potential (2) – Depolarization – Hyperpolarization – ***Refractory period
NEUROTRANSMITTERS • Are either excitatory v. inhibitory • Ex: Acetylcholine (Ach), its binding to receptors opens up sodium channels and allows an influx of Na+ ions and reduces membrane potential which is referred to as Excitatory Postsynaptic potential(EPSP). An action potential is generated when the polarization of the postsynaptic membrane reaches threshold. • example is the neurotransmitter Gamma Aminobutyric Acid (GABA). The binding of GABA to receptors increases the flow of chloride (CI-)
Page 6 – Demo Excitatory v. Inhibitory
Reuptake • The sending neuron reabsorbs any neurotransmitters left at the synapse
SSRI (Selective Serotonin Reuptake Inhibitor)
Drugs can be…. . • Agonists- make neuron fire • Antagonists- stop neural firing • Reuptake Inhibitors- block reuptake
Agonist • Substance that mimics or has a similar effect of a neurotransmitter Antagonist • Substance that inhibits the effects of a neurotransmitter
Use the following terms to complete the fill ins on p. of packet (1 – 11) • • • Dendrite Excitatory Axon terminal Ions Spike/Action potential Axon Depolarized EPSP/ threshold Reuptake • • • Resting potential Neurotransmitters Permeable Refractory period Synapse inhibitory Myelin sheath All or none Inhibiting Exciting
Use the following terms to complete the fill ins on back of p. 9 of packet (11 – 17) • • • L-Dopa Agonist serotonin Blood brain Receptors Parkinson Opium Heroin Antagonist • • • Endorphins Acetylcholine Reuptake GABA Curare Norephinephrine Dopamine (2 X) Increase Decrease
• play multiple roles and their functions overlap • their impact is determined by… - level - location - receptor it binds with
Sensory Neurons • Imagine living a life without pain? How is pain adaptive? • Watch and see …. • http: //www. youtube. com/watch? v=1 v. Ls. Z_d. X FAg&desktop_uri=%2 Fwatch%3 Fv%3 D 1 v. Ls. Z_d XFAg&app=desktop
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