Neurobiology: Understanding Neurons, Neurotransmission, and Neurotransmitters, Quizzes of Biology

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TERM 1 Neurons DEFINITION 1 * An electrically excitable cell that processes and transmits information by electrical and chemical signaling* Transfer information within the body* Transmit sensory information, control heart rate, coordinate hand and eye movement, record memory, generate dreams, and much more* Neurons > Nerves (bundle of neurons) > Ganglia (Large groups) > Brain (Even larger groups) TERM 2 Snails and Fleas DEFINITION 2 * The cone snail disables its prey's nervous system* Every flea medicine short-circuits the neurotransmitters in dogs TERM 3 Central Nervous System DEFINITION 3 * Includes the brain and the spinal cord* The neurons that carry out information are organized in the CNS TERM 4 Peripheral Nervous System DEFINITION 4 * The actual nerves that carry the information into and out of the CNS are the Peripheral Nervous System* The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. * A bundle of neurons make up nerves TERM 5 Sensory Neurons DEFINITION 5 *Sensory neurons are typically classified as the neurons responsible for converting external stimuli (light, sound, touch) from the environment into internal stimuli (blood pressure, muscle tension).* This information is sent to processing centers in the brain or ganglia* Then neurons in the brain or ganglia integrate (analyze and interpret) the sensory input, taking into account the immediate context and the animal's experience* Nerve cells designed to take on of our five senses and translate it into an electrical signal TERM 6 Interneurons DEFINITION 6 *An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways. * The vast majority of nerves in your brain* Form the local circuits connecting neurons in your brain TERM 7 Motor Neurons DEFINITION 7 * Transmit signals to muscle cells, causing them to contract TERM 8 Cell Body DEFINITION 8 * Most of the neurons organelles, including its nucleus, are located in the cell body TERM 9 Dendrites DEFINITION 9 * Numerous highly branched extensions* Dendrites are the branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. * Long projections* Where signals come into the cell TERM 10 Axon DEFINITION 10 *An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma.* Transmits signals to other cells* Where signals go out of the cell* Long projections TERM 21 Depolarization DEFINITION 21 * A reduction in the magnitude of the membrane potential* Involves gated sodium ion channels* Move it closer to neutral* Makes the inside of the membrane less negative* NA+ flowing in TERM 22 Graded Potentials DEFINITION 22 * The shift in the membrane due to hyperpolarization or depolarization* Has a magnitude that varies with the strength of the stimulus, with a larger stimulus causing a greater change in the membrane potential* Induces a small electrical current that leaks out of the neuron as it flows along the membrane TERM 23 Action Potential DEFINITION 23 * If a depolarization shifts the membrane potential sufficiently, the result is a massive change in the membrane voltage called Action Potential* A massive change in the membrane voltage* Action Potential = a huge depolarization = a neuronal signal* Has a constant magnitude and can regenerate in adjacent regions of the membrane* Moves down the axon* TERM 24 Process of Action Potential DEFINITION 24 1) Resting = most channels closed, NA+/K+ pump running, voltage-gated potassium channels are closed2) When a stimulus depolarizes the membrane, some gated NA+ channels open, which allows more NA+ to flow in and increases depolarization3) Threshold is crossed, huge potential spike (rising phase), all NA+ channels open4) Voltage channels inactivate causing NA+ to close, K+ channels open, K+ flows out, potential drops rapidly (falling phase)5) Potential undershoots and K+ channels close, restoring resting TERM 25 Refractory Period DEFINITION 25 * "Downtime"* Refractory Period = neuron rest* Ensures all signals in the axon travel in one direction, from cell body to axon terminals* Due to the inactivation of sodium channels TERM 26 Myelin Sheath DEFINITION 26 * Coates the Axon* Electrical insulation TERM 27 Oligodendrocytes (CNS) DEFINITION 27 * Glia in the Central Nervous System that produces myelin sheaths* Wrap axons in many layers of membrane (lipid; poor conductors of electrical current) TERM 28 Schwann Cells (PNS) DEFINITION 28 * Protect it from the extracellular matrix* Schwann cells or neurolemmocytes are the principal glia of the peripheral nervous system. TERM 29 Nodes of Ranvier DEFINITION 29 *Myelin sheath gaps or nodes of Ranvier are the gaps (approximately 1 micrometer in length) formed between the myelin sheaths generated by different cells. * Restrict voltage-gated sodium channels* Depolarized Region* Electrical impulses jump between the Nodes of Ranvier TERM 30 Saltatory Conduction DEFINITION 30 * The propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials without needing to increase the diameter of an axon.* Jumping between Nodes of Ranvier* The whole process where it jumps and conducts current by opening and closing sodium and potassium channels TERM 31 For the membrane potential to go UP (become more positive) the most important event is...? DEFINITION 31 * Sodium Channels OPEN TERM 32 Electrical Synapse DEFINITION 32 * Contain gap junctions which do allow electrical current to flow directly from one neuron to another/* Synchronize the activity of neurons responsible for certain rapid, unvarying behaviors TERM 33 Chemical Synapse DEFINITION 33 * Involve the release of a chemical neurotransmitter by the synaptic neuron* Chemicals = neurotransmitter* In synaptic vesicles* The chemical signal is a neurotransmitter TERM 34 Synaptic Vessels DEFINITION 34 * At each terminal. the presynaptic neuron synthesizes the neurotransmitter and packages it in multiple membrane compartments called SYNAPTIC VESSELS TERM 35 Postsynaptic Cell DEFINITION 35 * Designed so nerve cells aren't going off all the time TERM 46 Glutamate DEFINITION 46 * Natural neurotransmitter* When bound to any of several types of ligand-gated ion channels, it has an excitatory effect on postsynaptic cells TERM 47 Gamma Amino Butyric Acid (GABA) DEFINITION 47 * The chief inhibitory neurotransmitter in the mammalian central nervous system. * The neurotransmitter at most inhibitory synapses in the brain* BInding of GABA to receptors in postsynaptic cells increases membrane permeability to CL-, resulting in IPSP TERM 48 Glycine DEFINITION 48 * Acts at inhibitory synapse in parts of the CNS that lie outside of the brain* There glycine binds to an ionotropic receptor that is inhibited by strychnine (rat poisoning chemical) TERM 49 Biogenic Amines DEFINITION 49 * Neurotransmitters that are synthesized from amino acids* Include Epinephrine, Norepinephrin, Dopamine, and Seratonin TERM 50 Neuropeptides DEFINITION 50 * Short chains of amino acids* Serve as neurotransmitters that operate via metabotropic receptors* Include endorphins (feel pleasure) and substance P (opiate receptors; mimic endorphines) TERM 51 Gases DEFINITION 51 * Act as local regulators* Released by neurons in vertebrates* Includes nitric oxide (NO) and carbon monoxide (CO)* NO is not stored in cytoplasmic vesicles, but instead are synthesized on demand* CO regulates the release of hypothalamic hormones