Term
| how is the axon structually specialised? |
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Definition
| it is long thin and has many microtubules |
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Term
| the action potential involves the flux of which two ions across the axonal membrane? |
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Definition
K+ and Na+
sodium ions flow in and potassium ions flow out |
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Term
| describe the structure of dendrites |
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Definition
short, bristle like, no sheath, contact terminals of other neurons
dendrites do not arise from the axon but generally from the cell body |
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Term
| oligodendrocytes, schwaan cells and astrocytes are all types of what cells? |
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Definition
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Term
true or false?
action potentials originate at the trigger zone, they can jump from one node of ranvier to the next one and they involve the influx of sodium ions into the axon? |
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Definition
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Term
| an o.............. provides part of the myeline sheath for many axons in the CNS where as a s............ cell provides part of the myeline sheath for a single axon in the PNS. |
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Definition
oligodendrocyte, schwaan
this is the fundamental difference between myelination in the CNS and the PNS |
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Term
| the c........ is part of the brain that coordinates balance and posture where as the brain s....... is responsible for respiratory control |
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Definition
cerebellum, stem
the cerebellum is located at the back of the brain and coordinates movement blanc, posture and maintains muscle tone. the brain stem is as the top of the spinal cord and controls respiration, the cardiovascular sytem, swallowing and vomiting. |
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Term
which of the following is NOT a criteria for a chemical substance to be accepted as a neurotransmitter?
- endogenously added agonist drug mimics exact action of chemical substance
- synthesised in presynaptic nerve cell
- has an excitatory effect on post synaptic neuron
- specific mechanism exist for removing it from the synaptic cleft
- present at presynaptic terminals within synaptic vesicles
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Definition
has an excitotory effect on the post synaptic neuron.
eg the amino acids glycine and GABA have an inhibitory effect on the post synaptic nerve cell but are still defined as neurotransmitters |
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Term
| explain how infomration is transfered at a chmical synapse |
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Definition
| calcium flows into presynaptic nerve terminal > synaptic vesicles fuse with the pre synaptic membrane > transmitter is released into synaptic cleft > transmitter binds with receptors in the post synaptic membrane > a response is ellicited in the post synaptic neuron. |
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