Nerves

C=Channel, RP= Resting Potential, Na+= Sodium ions, K+= Potassium ions, VG= Voltage Gated, PD= Potential Difference, TF=Therefore, MS=myelin Sheath, NoR= Nodes of Ranvier, N= Node, SK= Synaptic Knob, Ca2+= Calcium ions,  NT=Neurotransmitter, PSM=Post Synaptic Membran

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  • Created by: Arianne
  • Created on: 09-01-13 14:02
Stages of a nerve impulse?
Stumulus, Receptors, CNS, Effectors, Response
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Structure of Motor Neurones
Short dentrites from relay neuron in CNS, cell body at end of cell, nucleus in cell body, long axon, axon terminal attaches to effector cells.
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Structure of Sensory Neurone
Long dendrite from receptors, cell body at end of dentrite-begining of axon, short(er) axon than motor neurone. Axon terminal attaches to relay neurone in CNS.
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Structure of Relay Neurone
Short axon, many axon terminals. Found inside CNS and brain.
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What is resting potential?
-60 to -70mV
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Threshold potential?
-50mV
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Stages of Action Potential?
RP, stimulus excites neurone membrane, Na+ Cs open. Depolarisation (if PD reaches TH) VG Na+ Cs open. Repolarisation - +30mV, Na+ Cs close, VG K+ Cs open. Hyperpolarisation - repolarisation overshoots, PD more -ve then RP.
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Define Refractory Period.
Time for cell membrane to recover TF can't be excited straight away.
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Larger stimulus does not cause ..., causes...
Does not cause larger AP, causes more frequent AP.
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Why does mylineation speed up APs?
MS = electrical insulator, depolarisation only occurs at NoR, Neurone's cytoplasm conducts enough EC to depolarise next node TF impulse jumps via SALTATORY CONDUCTION from N to N.
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Structure of Synapse?
Synaptic Knob (inside SK, mitochondria, vesicles with NT, Ca2+ channels), Synaptic cleft (contains NT and enzymes for NT breakdown), post synaptic membrane contains NT receptors and Na+ channels (to beging the next AP).
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How do NT transmit nerve impulses between neurones?
AP triggers Ca2+ influx, Ca2+ influx causes NT release, NT triggers AP in PSM.
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Synapse functions?
Allow AP to be dispersed or amplified, summation and ensure impulse only travels one way.
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Example of NT?
Acetylcholine
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Example of NT enzyme in synaptic Cleft?
Acetylcholine Esterase
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Multiple Sclerosis occurs when neurons...?
Become unmylineated which slows rate of transmission.
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Other cards in this set

Card 2

Front

Structure of Motor Neurones

Back

Short dentrites from relay neuron in CNS, cell body at end of cell, nucleus in cell body, long axon, axon terminal attaches to effector cells.

Card 3

Front

Structure of Sensory Neurone

Back

Preview of the front of card 3

Card 4

Front

Structure of Relay Neurone

Back

Preview of the front of card 4

Card 5

Front

What is resting potential?

Back

Preview of the front of card 5
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