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| Question | Answer |
| Neurons (Def.) | - Basic units of the nervous system - Cells that receive, integrate, and transmit info in the nervous system |
| How do neurons communicate? | - They communicate with each other through chemical signals - They operate internally by electrical impulses |
| Central Nervous System (CNS) contains? | Consists of the brain and the spinal cord, both contain massive numbers of neurons |
| Neural Networks (Def.) | Neurons that communicate selectively with other neurons to form neural networks |
| Peripheral Nervous System (PNS) contains? | - All nerve cells in the body that are not part of the CNS - The PNS includes the somatic and autonomic nervous systems |
| What does the PNS do? | The PNS sends info to the CNS |
| What does the CNS do? | The CNS organises and evaluates info from the PNS and directs the PNS to perform specific behaviours |
| Sensory Neurons (Def.) | These neurons detect info from the physical world and pass that info to the brain, usually through the spinal cord |
| Motor Neurons (Def.) | These neurons direct muscles to contract or relax, producing movement |
| Interneurons (Def.) | These neurons communicate within local or short-distance circuits, integrate neural activity with a single area rather than transmitting info to other organs |
| Reflexes (Def.) | - Automatic motor responses that occur before we think about the response - Neurons simply convert sensation into action |
| Dendrites (Def.) | Branchlike extensions of the neuron that detect info (chemical signals) from other neurons |
| Cell Body (Def.) | The site in the neuron where info from thousands of other neurons is collected and integrated |
| Axon (Def.) | Electrical impulses are transmitted down a long, narrow outgrowth known as the axon, and they can vary in length. |
| Terminal Buttons (Def.) | At the ends of axons, small nodules that release chemical signals from the neuron into the synapse |
| Synapse (Def.) | - The gap between the axon of a "sending" neuron and the dendrites of a "receiving" neuron - The site where chemical communication occurs between neurons |
| Membrane of Neuron (Def.) | - A fatty barrier that does not dissolve in the watery environment inside and outside the neuron - Semipermeable - Regulates concentration of electrically charged molecules |
| Ion Channels (Def.) | Specialised pores that allow ions to pass in and out of the cell when the neuron transmits signals down the axon |
| Resting Membrane Potential (Def.) | The difference between the electrical charge inside and outside a neuron when it is not active |
| What is the charge inside and outside a neuron when it is not active? | The inside of an inactive neuron is slightly more negative than the outside |
| Polarised (neurons) | - When a neuron has more negative ions inside than outside - This creates the electrical energy necessary to power the firing neuron |
| What type of ions are involved in the polarisation of a neuron? | - Sodium ions are positively charged - Potassium ions are negatively charged |
| Sodium-Potassium Pump (Def.) | The pump increases potassium and decreases sodium inside the neuron, helping to maintain the resting membrane potential |
| Action Potential (Neural Firing) (Def.) | The electrical signal that passes along the axon and causes the release of chemicals from the terminal buttons |
| Excitatory Signals (Def.) | Depolarize the cell membrane, these signals increase the likelihood that the neuron will fire |
| Inhibitory Signals (Def.) | Hyperpolarize the cell, these signals decrease the likelihood that the neuron will fire |
| When is an action potential generated? | If the total amount of excitatory input surpasses the neuron's firing threshold and the neuron is depolarized |
| Myelin Sheath (Def.) | A fatty material, made up of glial cells, that insulates some axons to allow for faster movement of electrical impulses along the axon |
| Nodes of Ranvier (Def.) | - Small gaps of exposed axon, between the segments of myelin sheath, where action potentials take place - Action potentials pause briefly at each node to recharge |
| All-or-None Principle (Def.) | - The principle that when a neuron fires, it fires with the same potency each time. A neuron either fires or not. - A neuron will fire more frequently is the stimulation is strong |
| Presynaptic Neuron (Def.) | The neuron that sends the signal |
| Postsynaptic Neuron (Def.) | The neuron that receives the signal |
| Neurotransmitters (Def.) | - Chemical substances that transmit signals from one neuron to another - These chemicals are made in the axon and are stored in vesicles |
| Receptors (Def.) | - Specialised protein molecules on the postsynaptic membrane - Neurotransmitters bind to these molecules after passing across the synapse |
| Reuptake (Def.) | The process whereby a neurotransmitter is taken back into the presynaptic terminal buttons, thereby stoping its activity |
| Enzyme Deactivation (Def.) | Occurs when an enzyme destroys the neurotransmitter in the synapse |
| Autoreceptors (Def.) | - Monitor how much neurotransmitter has been released into the synapse - When an excess is detected, the autoreceptors signal the presynaptic neuron to stop releasing the neurotransmitter |
| Antagonists (Def.) | Drugs and toxins that inhibit the actions of neurotransmitters |
| Agonists (Def.) | Drugs and toxins that enhance the actions of neurotransmitters |
| Acetylcholine (ACh) (functions) | - Motor control over muscles - Learning, memory, sleeping, and dreaming |
| Botulinum Toxin (Def.) | This neurotoxin inhibits the release of acetylcholine (ACh), resulting in paralysis of muscles and often death |
| Epinephrine (functions) | - A monoamine neurotransmitter - Energy |
| Norepinephrine (functions) | - A monoamine neurotransmitter - Arousal, vigilance, and attention |
| Serotonin (functions) | - A monoamine neurotransmitter - Emotional states and impulsiveness - Dreaming |
| Dopamine (functions) | - A monoamine neurotransmitter - Reward and motivation - Motor control over voluntary movement |
| GABA (gamma-aminobutyric acid) (functions) | - Primary inhibitor of action potentials - Anxiety reduction |
| Glutamate (functions) | - Primary excitator of action potentials - Learning, memory |
| Endorphines (functions) | - Neurotransmitters involved in natural pain reduction and reward |
| Selective Serotonin Reuptake Inhibitors (SSRIs) | A drug that blocks serotonin reuptake and thus leaves more serotonin at the synapse to bind with the postsynaptic neurons |
| Parkinson's Disease | - A degenerative and fatal neurological disorder marked by muscular rigidity, tremors, and difficulty initiating voluntary action - Lack of dopamine may be involved in movement problems |
| Deep Brain Stimulation | Involves surgically implanting electrodes deep within the brain and then using mild electrical stimulation in the regions affected by Parkinson's disease |
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