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ANAT1018 study notes Week 8 Nervous Tissue Nervous Tissue Consists of nerve cells ( neurons ) and glial cells ( neuroglia ) Neurons have the capacity to receive impulse from other neurons or receptor organs and transmit impulses to other neurons or effector organs Most neurons contain three cellular structures or functional segments: o Receptive segment (cell bodies and dendrites) Cell body (perikaryon, soma) One large nucleolus, and one or several, prominent nucleoli (not nuclei) and nissl bodies Size varies from 5 to 130 micrometers Connected to only one axon through it’s axon hillock Is receptive to stimuli and hence the site of synapses ( axosomatic synapses ) Protein synthesizing centre from the whole neuron Dendrites Receptive to stimuli, bring stimuli from the environment to the cell body To increase receptive area of a neuron, usually numerous dendrites per neuron These dendrites again contain numerous processes ( dendrite trees ) o Conductive segment (axon) Axon Each neuron contains only one axon which is connected with the cell body through the axon hillock Axon hillock is the only site of neuron where action potential is initiated, lacks nissl bodies The only structure in the neuron that conducts impulses away from the bell body Only axons can be mylinated through glial cells o Transmissive segment (synapse) Please note that LIFT does not warrant the correctness of the materials contained within the notes. Additionally, in some cases, these notes were created for previous semesters and years. Courses are subject to change over time, both in content and scope of assessment. Thus the information contained within may or may not be assessed this semester, or the information may have been superseded. These notes reproduce some copyrighted material, the use of which has not always been specifically authorised by the copyright owner. We are making these materials available for the purposes of research and study and as such believe that this constitutes fair dealing with any such copyrighted material pursuant to s 40 Copyright Act 1968 (Cth). Downloaded by Ivy Jiang ([email protected]) lOMoARcPSD|8329422
Morphological classification of neurons 1. Axononic neurons : axons and dendrites cannot be differentiated with certainty. Mainly found in brain and special sense organs 2. Unipolar neurons have a single process (neurite) arising from the cell body 3. Unipolat neurons (pseudo) have a single process (neurite) arising from the cell body. First develop as bipolar neurons and convert later to unipolar. Mainly found in sensory root ganglia of spinal nerves 4. Bipolar neurons have two processes arising from the cell body (one axon and one dendrite). Very rare and are only present in special sensory structure including the retina, olfactory epithelium and vestibular and cochlear ganglia 5. Multipolar neurons pocssess numerous processes airing from the cell body (a single axon and numerous dendrites). Most neurons belong to this category motor neurons Three Basic Types of Neurons 1. SENSORY NEURONS ( A

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