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NadiaA

Neural Physiology
LO:
 Neuron structure
 Organization of nervous system
 Understand the functional organisation of the spinal nerves
 Understand the functional organisation of the brain
Need to know:
 Terms used to describe the structure and function of neurons
 The basic tripartite vertebrate CNS plan
 Basic plan and terminology describing mammalian central and peripheral nervous systems
Neurobiology- branch of biology that studies the nervous system at all levels
Levels include:
 cellular e
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electrophysiology
 Network e
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reflex circuits
 Systems e
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structure-function study of CNS and PNS
Via careful staining under microscopes and studying brain tissue two theories formed:
1
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Cell theory/neuronal theory by Ramon Cajal The nervous system is made out of individual cells (neurons) that are interconnected
at synaptic junctions
 cells are specialised to process info
 Neurons are directional as cell is polarised
Using light microscopes was hard as it used natural light and so wasn’t very effective
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Nervous system provides rapid and focussed signalling over long distances
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g
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Receive and integrate incoming signals
2
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Transmit signal to other cells
Neurons differ in ways:
1
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g
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Differ in the mechanism of signal conduction
3
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g
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Sensory neurons
2
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Motor neurons/ motoneurons
The classification is based on their function
Notice the difference in structure e
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number of dendrites etc
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g
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Note the differences in the structures, e
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which one is unipolar, which is bipolar etc!
Neuron classification is based on structure;
Structural classes of neurons
Multipolar
 Many dendrites
 One axon
Bipolar
 One dendrite (may have branches)
 One axon
Unipolar
 Single process extending from cell body
 May split to form afferent and efferent branches
Glial cells- the ‘other’ cells of the nervous system

-More abundant than neurons
90% of cells in human brain are glial cells
-Do not generate or conduct APs
-Do not form synapses with neurons
-Take up and release neurotransmitters
-Support the functioning of neurons e
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To surround neurons and hold them in place,
2
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To insulate one neuron from another,
4
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Cerebrum (consists of paired cerebral hemispheres)
2
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Midbrain (tectum)
4
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Medulla
6
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g
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Vagus
The vertebrate CNS
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Cerebrospinal fluid bathes cells of CNS, for protection, cushioning, immune roles too
Encased in bone
Surrounded by meninges tissue- for protection
Spinal cord comes out of each segment and each has a afferent (from dorsal) and efferent
neuron (from ventral)
 Dorsal: sensory input
 Ventral: motor output
Interneuron and motor neuron cell bodies lie in the grey matter of spinal cord
Sensory cell bodies lie outside the spinal cord

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