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45 Cards in this Set
- Front
- Back
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Term: nerve |
A collection of dendrites |
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What are the main purposes of dendrites? |
Increase the surface area of soma And Carry signals TOWARD the soma |
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Term: soma and dendrites |
Input zone Receiving region of a neuron |
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Term: axon |
Carries signals AWAY from the soma "Conducting zone" |
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Term: terminal button |
"output zone" Where signal leaves the neuron |
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Term: motor neuron |
Carry signal AWAY from the CNS Aka: efferent neurons |
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Term: sensory neuron |
Carry signal TOWARD the CNS AKA afferent neurons |
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What is typically 2 neurons long? |
Autonomic motor pathway |
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Term: ganglion |
A group of neuron cell bodies located outside CNS |
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This neuron is found before the ganglion |
Preganglionic neuron |
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This neuron is found after the ganglion |
Postganglionic neuron |
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Term: synapse |
The connection between the button and another cell |
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The five parts of the CNS |
Cranial Cervical Thoracic Lumbar Sacrum |
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Term: neurotransmitters |
Chemical messengers released from the terminal button of a neuron that carry signals to another cell |
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What are the two types of nerves found in the peripheral nervous system? |
Somatic nerves (voluntary) And Autonomic nerves (involuntary) |
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What are the two types of somatic nerves? |
Motor neurons (carry impulses from CNS to effectors) And Sensory neurons (carry impulses from sensory receptors to the CNS) |
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How is the autonomic nervous system divided? |
Sympathetic and parasympathetic |
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Where do autonomic nerves start and end? |
Start in CNS, synapses at ganglion, then to effector organ |
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Term: excitable cells |
Cells that can use membrane potential to do work |
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Explain sympathetic nerves |
They originate in the thoracic and lumbar regions of the CNS. Their preganglionic neurons are very short. Preganglionic neurons release acetylcholine. (Most) Postganglionic nerves release norepinephrine |
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Explain parasympathetic nerves |
Originate from the brain (cranial) and lower spinal cord (sacrum) Preganglionic neurons are long Both pre and post nerves release acetylcholine |
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Term: threshold |
The minimum level of stimulus needed for a neuron to respond (once reached it is all-or-none response and automatic) |
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Term: all-or-none response |
Once threshold is reached, the neuron "fires" at maximum magnitude. If threshold is not reached, there is no "firing" at all |
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What causes membrane potential? |
It is created by a difference in the number of charges outside a membrane compared to inside a membrane (separation of opposite charges across a membrane) |
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"Conduction without decrement" refers to what? |
Impulse stays the same all along the length of the axon |
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Three ways ions move through membranes |
Na/K pumps (always running) Leak channels (always working) Na and K gates (react to change in voltage) |
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Term: resting potential |
@ -70mV Na concentration is higher outside the cell and K concentration is higher inside the cell. |
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Explain depolarization |
-At threshold Na+ gates open and Na+ diffuses into cell. -Membrane potential changes from -50mV to +30mV -At +30mV Na+ gates close |
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Explain Repolarization |
At +30mV K+ gates open and K+ diffuses out of cell Membrane potential changes from +30mV to -70mV -Hyperpolarization occurs |
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Explain hyperpolarization |
Membrane potential falls below -70mV until K+ gates close. Membrane potential resets to resting potential at -70mV |
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A) threshold B) resting potential C) hyperpolarization D) K+ gates close E) Na+ gates open F) depolarization G) repolarization H) Na+ gates close/K+ gates open |
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These are the spaces in between myelin sheaths |
Nodes of Ranvier |
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What are the mechanisms used to remove neurotransmitters? |
Diffusion, enzymes, reabsorption |
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Explain oligodendrocytes and Schwann cella |
Oligodendrocytes form myelin sheaths for several axons and dendrites at once. Located in CNS Oli prevents regrowth of axons and dendrites with an inhibitor protein. Schwann cells only produce a single patch of myelin. Located in PNS. Schwann helps the regrowth of axons and dendrites. |
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Explain how a chemical synapse works |
Stimulus reaches the terminal button Ca gates open and Ca diffuses into cell Neurotransmitters are released by exocytosis and diffuse across synaptic gap NT attach to post synaptic receptors This alters the post synaptic membrane potential |
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What are the functions of cerebral spinal fluid? |
Cushion and protect CNS and brain Carry nutrients, white blood cells and hormones Produced by choroid plexuses in brain ventricles |
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WHY does an action potential move along a cell? |
Local Current Flow: At the height of an AP, the opposing charges on either side of the depolarized patch are attracted to each other and this depolarizes adj patches to threshold |
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What are the parts required for a reflex arc? Where do signals enter and leave the spinal cord? |
sensory receptor to carry impulse to CNS Interneuron Motor neuron that leaves CNS Effector muscle which contracts They enter through dorsal root and leave through ventral root |
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What does an action potential only move in one direction |
Refractory period: The Na+ voltage gates need time to reset. |
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What are the brain's grooves and ridges called |
Grooves- sulci Ridges- gyri |
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Explain temporal and spatial summation |
Temporal- two or more signals arrive from single input Spatial- two or more signals arrive from two or more inputs |
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What are the layers of the meniges |
Dura mater Arachnoid mater Pia mater |
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The 3 main sections of the brain |
Hindbrain - includes medulla, cerebellum, and pons Midbrain Forebrain - includes thalamus, hypothalamus, and cerebrum |
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