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90 Cards in this Set
- Front
- Back
What kind of system is the nervous system?
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It is a communication system
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What is the main difference between the nervous system and the endocrine system?
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The difference is the speed of the responses.
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How fast are hormone actions?
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Minutes to hours to days
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How fast are nerve impulses?
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1 milliseconds
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What is a neuron?
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A neuron is a individual nerve cell
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What region is the axon? What does it do?
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It is the region in the middle that generates impulses and conduction.
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What is a nerve?
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A nerve is a bundle of neurons (axon) in the peripheral nervous system
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What is the peripheral nervous system?
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All neurons outside the brain and spinal cord
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What is the central nervous system?
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Brain and spinal cord
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What are tracts?
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Bundle of nerves in he brain
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What does innervate mean?
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Innervate means provide with a nerve supply
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What is a synapse?
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A synapse is the point of closest contact between two neurons
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Where is a neurotransmitter secreted from?
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It is secreted from a presynaptic neuron
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What does the NT do after it's been secreted from the presynaptic neuron?
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It binds to post-synaptic neurons which may excite or inhibit firing of APs.
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What do sensory receptors respond to?
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They respond to internal and external changes
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What pathway does information carried by the sensory neurons travel on? Where does it go?
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Afferent pathway. Carried TOWARD the CNS
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Where do association neurons carry out integration entirely within?
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Entirely within the CNS!
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What 3 processes are part of integration?
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1. Interpretation of sensory input
2. Store and retrieve information, make decisions 3. Initiate motor output |
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What do motor neurons do?
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Motor neurons signal to effectors to produce a response
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What are effectors?
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Muscles and glands
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Motor neurons send information on what pathway? Where does it go?
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Efferent pathways. Information travels AWAY from CNS
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What does SAME stand for?
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Sensory Afferent Motor Efferent
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What does the structure of neurons allow neurons to do?
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Structure of neurons lets them carry out their functions
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Neurons are what kind of cells?
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Excitable cells
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When neurons are stimulated, how do they respond?
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Neurons respond by firing action potentials
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What are action potentials?
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APs are long distance electrical signals
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What is a multipolar neuron?
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A multipolar neuron is a neuron with two or more dendrites coming off the neuron cell body
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What are the most common neurons?
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Association and motor neurons
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What are the four parts of a multipolar neuron?
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Cell body, dendrites, Axon, and Axon terminals
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What is the biosynthetic center? What does it do?
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The biosynthetic center is in the cell body that carries out cellular functions such as protein synthesis and NT synthesis
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Dendrites and the cell body make up what region on a neuron?
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Receptive region
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What are dendrites?
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Dendrites are short cytoplasmic processes
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What do dendrites do?
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Dendrites are the "antennae" to receive input from other neurons or sensory receptors
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What do dendrites and cell bodies produce?
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Dendrites produce excitatory post-synaptic potentials and inhibitory post-synaptic potentials
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How many axons are there per cell?
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One!
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How long are axons?
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Axons can be short or long (up to 3 feet).
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Axons arise from what part of a neuron?
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Axons arise from the axon hillock
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What is the axon hillock?
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It is the trigger zone where action potentials are initiated
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Where are action potentials initiated?
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At the axon hillock, or trigger zone.
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The axon makes up what region on a neuron?
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Axons make up the conducting region on neurons
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What are axon terminals?
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Axon terminals are the secretory region of neurons that secrete NT molecules.
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What are NTs?
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NTs are chemicals that may excite or inhibit the post-synaptic neuron
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What does the NT Acetylcholine (ACh) do?
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ACh causes skeletal muscles to contract
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What does the NT Norepinephrine (NE) do?
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NE causes smooth muscle to contract
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What cells form myelin in the PNS?
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Schwann cells
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What cells form myelin in the CNS?
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Oligodendrocytes
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Schwann cells wraps around the axon to form what?
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To form concentric layers of phospholipids
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What is the purpose of myelin?
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Electrical Insulation
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What are the functions of myelin?
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Electrically insulates the axon and to increase the speed of nerve impulse transmission
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How fast do unmyelinated fiber conducts?
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Unmyelinated fiber conducts APs at 1 meter/sec
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How fast does myelinated fiber conducts?
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Myelinated fiber conducts APs at up to 150 meters/sec
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Neuron signals occur to due to what?
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Ions entering and leaving
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What is a graded potential?
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A graded potential is a short distance electrical signal
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Where do graded potentials occur?
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Cell body/Dendrites in the receptive region
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What is the purpose of GPs?
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Excite or inhibit action potentials
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What are action potentials?
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APs are long distance electrical signal
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Where do APs originate?
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Trigger zone on the axon
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What is the purpose of APs?
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To set off NT secretion
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Where do NTs originate?
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NTs originate in the axon terminals
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What is the purpose of NTs?
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NTs excite or inhibit post-synaptic neuron. NTs set off graded potentials
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What is another name for graded potentials?
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Post-synaptic potentials
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What sets off the three signals in a neuron?
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The opening of gated ion channels
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What do ions do when gated channels open?
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Ions diffuse through the channel down their concentration gradients
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How do ions diffuse?
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Channel mediated facilitated diffusion
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GP occur due to the diffusion of what ions?
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Na+, K+, or Cl-
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APs occur due to the diffusion of what ions?
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Due ONLY to Na+ and K+
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NT secretion occurs due to the diffusion of what ions?
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Ca+2 (into the cell)
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Ion diffusion in the receptive region sets off what signal?
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Graded potential
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Leak channels are always what?
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Leak channels are always open!
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Where are leak channels located?
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All over the neuron
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There are more leak channels for what ion?
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More leak channels for K+
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What are leak channels responsible for?
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Leak channels are responsible for the resting membrane potential
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What are the two main types of gated channels?
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Chemically-gated channels and voltage-gated channels
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What is another name for chemically gated channels?
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Ligand-gated channels
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What chemical opens chemical-gated channels?
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NTs!
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Where are chemically gated channels located?
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In the plasma membrane of the receptor region in neurons
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Voltage-gated channels open and close due to what?
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They open and close due to voltage changes
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What is voltage?
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Voltage is the separation of charge across the membrane
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The inside of a neuron has normally what charge?
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Negative charge
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When the inside of a neuron is negative, the voltage gated channels are what?
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Closed
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When the inside of the neuron becomes more positive, the channels what?
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Open
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Na+ and K+ voltage gated channels are located where in a neuron?
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ONLY located on the Axon
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Which ion voltage gated channel opens first?
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Na+
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Which ion voltage gated channel opens second?
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K+
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Voltage-gated channels are responsible for what?
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APs!
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Ca+2 voltage gated channels are located where in the neuron?
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Located on the axon terminals
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When do Ca+2 voltage-gated channels open when AP arrives and allows Ca+2 to do what?
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Allows Ca+2 to enter the neuron
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Ca+2 voltage-gated channels trigger what to occur?
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Triggers NT secretion
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What are the 3 overlapping functions of the nervous system?
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1. Sensory Input
2. Integration 3. Motor Output |
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What is the immediate effect in the post-synaptic neuron when the chemically gated channels open?
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Graded potential!
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