Term
| t/f the nervous system processes information & forms action potentials |
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Definition
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Term
| t/f damage to individual parts of the brain can have dramatic consequences |
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Definition
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Term
| what is the function of neurons? |
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Definition
| they generate & transmit electrical signals (called action potential) down axons |
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Term
| axons are collectively called what? |
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Definition
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Term
| afferent neurons do what? |
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Definition
| carry information to the nervous system |
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Term
| efferent neurons do what? |
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Definition
| carry information from the nervous system to effectors |
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Term
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Definition
| communicate between afferent & efferent neurons |
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Term
| glia function to do what? |
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Definition
| support neurons physiologically, immunologically, & metabolically |
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Term
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Definition
| high numbers of neurons organized into clusters |
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Term
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Definition
| the enlarged, centralized integrative center of ganglia |
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Term
| the central nervous system is comprised of what? |
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Definition
| the brain & spinal cord (most of the cells are found here) |
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Term
| what comprises the peripheral nervous system? |
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Definition
| neurons that extend or reside outside of the brain & spinal cord |
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Term
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Definition
| junctions between neurons & target cells |
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Term
| the cell body of a neuron is comprised of what? |
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Definition
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Term
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Definition
| they bring information from other neurons or sensory cells to the cell body |
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Term
| what is the structure that commonly carries signals away from the cell body? |
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Definition
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Term
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Definition
| the ends of axons that come close to the membrane of the target cell to form a synapse |
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Term
| what are neurotransmitters? |
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Definition
| chemical signals at the synapse |
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Term
| t/f there are more neurons in the brain than glia? |
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Definition
| false - there are more glia in the brain than nuerons |
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Term
| what are the functions of glia cells? (7) |
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Definition
- can release neurotransmitters
- physically orient the neurons during development
- nourish the neurons
- insulate the axons
- provide protection from particles
- maintain the extracellular environment
- provide immune functions |
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Term
| What are oligodenrocytes? |
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Definition
| glial cells that provide an insulating membrane for the central nervous system |
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Term
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Definition
| glial cells of the peripheral nervous system that provide an insulating membrane |
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Term
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Definition
| the covering that increases the rapidity of transmission and gives the nervous system it's white shiny appearance. |
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Term
| multiple sclerosis is caused by what? |
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Definition
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Term
| what is the function of astrocytes? |
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Definition
| astrocytes contribute to the blood-brain barrier by surrounding the tiniest vessels in the brain, but fail with some fat soluble molecules such as alcohol & anesthetics |
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Term
| what is the function of microglia? |
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Definition
| act as macrophages & mediators of inflammatory responses in immune function |
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Term
| what is membrane potential? |
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Definition
| the difference in the electrical charge across the plasma membrane |
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Term
| which is more prevalent inside of a cell, K or Na? |
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Definition
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Term
| what causes a slightly negative charge on the inside of a cell? |
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Definition
| the leak of K from the inside to the outside of the cell |
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Term
| the Nernst equation calculates what? |
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Definition
| the value of the potassium equilibrium potential using the K concentrations on each side of the cell |
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Term
| what is resting potential? |
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Definition
| the steady state membrane potential |
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Term
| what are action potentials? |
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Definition
| dramatic shifts in membrane potential due to sudden ion channel openings & rapid closings "nerve impulse" |
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Term
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Definition
| a force that causes electrically charged particles to move between 2 points (electric potential difference); players are: Na, K, Ca, (-)Cl |
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Term
| The sodium potassium pump actively expels sodium (Na) from the inside of the cell and exchanges it for potassium (K) outside of the cell in what ratio? |
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Definition
| 3 sodium (Na) are expelled for 2 potassium (K) |
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Term
| Voltage-gated channels open or close in response to what? |
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Definition
| a change in the voltage across the plasma membrane |
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Term
| The most common open, or leak, channels are what type of channels? |
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Definition
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Term
| what is the electrochemical gradient? |
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Definition
| a combination of both the electrical forces & the chemical forces resulting from ion movement across a membrane |
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Term
| gated channels can be controlled by what? |
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Definition
| voltage, a chemical gradient, or mechanically |
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Term
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Definition
| when the inside of a neuron is less negative (closer to positive) as compared to its resting potential |
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Term
| what is hyperpolarization? |
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Definition
| the inside of a neuron becomes more negative than resting potential |
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Term
| what are action potentials? |
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Definition
| sudden, transient, large changes in membrane potential |
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Term
| action potentials change the membrane potential from -60mV to what? |
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Definition
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Term
| what is the course of an action potential? |
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Definition
- from the resting potential, sodium (Na) ion channels open causing depolarization
- positive reinforcement causes more sodium (Na) channels to open in the axon hillock
- once the threshold is met even more sodium ion channels open creating positive potential (action potential)
- the sodium voltage gates then close
- the potassium voltage gates open
- sodium gates have a refractory period
- and finally, resting potential is reestablished |
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Term
| why is action potential travel possible? |
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Definition
| because it is an all-or-non response & it is a self-regenerating event |
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Term
| why is action potential an all-or-none response? |
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Definition
| because the positive feedback of sodium channels ensures increase until the action potential is reached |
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Term
| why is action potential self-regenerating? |
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Definition
| because it stimulates the adjacent region to action potential and proceeds stepwise |
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Term
| larger diameter axons have more or less resistance? |
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Definition
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Term
| what is saltatory conduction? |
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Definition
| the propagation of axon potentials along myelinated axons from one node of Ranvier to the next node, increasing the speed of conduction of action potentials without needed to increase the diameter of axons |
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Term
| what is a chemical synapse? |
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Definition
| neurotransmitters from presynaptic cell induce a change in the postsynaptic cell |
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Term
| what are electrical synapses |
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Definition
| the action potentail spreads directly from the presynaptic to postsynaptic cell |
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Term
| Neuromuscular junctions are model chemical synapses which use what as a neurotransmitter? |
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Definition
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Term
| which are more common, chemical synapses or electrical synapses? |
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Definition
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Term
| where are neurotransmitters created? |
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Definition
| either in the axon terminal or sometimes in the cell body and then packaged by the Golgi apparatus & transported |
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Term
| what is a motor end plate? |
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Definition
| the modified part of the muscle cell plasma membrane (receiver) |
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Term
| what is the synaptic cleft? |
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Definition
| the actual empty space between the presynaptic and postsynaptic membranes |
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Term
| the action of a neurotransmitter depends on what? |
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Definition
| the receptor to which it binds |
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Term
| what are popular neurotransmitters? |
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Definition
acetylcholine
serotonin
endorphins
nitrous oxide
dopamine
norepinephrine |
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Term
| Learning & memory have been linked to what? |
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Definition
| there glutamate induced increased sensitivity in synaptic input because of TWO different receptors after high-frequency stimulation (Long-term potentiation) |
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Term
| How are neurotransmitters turned off? |
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Definition
| By either enzymatic destruction or diffusion |
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Term
| Prozac slows the diffusion of which neurotransmitter? |
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Definition
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