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8 Cards in this Set
- Front
- Back
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What is Nissle substance?
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a basophilic substance found in cytoplasm of neuron cell body, consisting of rough endoplasmic reticulum, free ribosomes, and polysomes
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Whay types of pigments can you find in neurons?
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melanin (dark coloured pigment) & lipofuscin (yellow/brown coloured undigested lipid material)
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What is the difference between unipolar, pseudounipolar, bipolar and multipolar neurons?
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-unipolar has only one process
-bipolar has two processes (eg. retina, vestibulococlear ganglion etc.) - multipolar has more than two processes -pseudo-unipolar is neuron that form as a bipolar cell and the two processes fuse |
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Write short notes on axons compared with dendrites
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both are neuron processes
axons are w/wo a myelin sheath (dend.-usually nonmyelinated) cytoplasm of axons doesn't contain Nissl bodies whereas dend. do. one neuron has only one axon while the neuron has usually >1 dend. Axon usually unbranched, whereas dend. has dendritic tree (profuse branches) Dend. are usually afferent & axon are efferent |
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What are the three different connective tissue sheaths that surround spinal nerves?
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1.epineurium
2.perineurium 3.endoneurium |
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Write short notes on the formation of the myelin sheath after the axon has achieved a 1:1 ratio with the Schwann cell
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1.the axon sits in a furrow on the Schwann cell surface
2.the furrow deepens and the Schwann cell starts wrap around the axon forming concetric lamellae 3.the cytoplasm is squeezed out of the lamellae after a few turns and compact myelin is formed |
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What is the difference between the major dense line and the intraperiod line?
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intraperiod line is formed by fusion of the outer Schwann cell cytoplasmic membranes. Major dense line is the prominent line on EM and is formed by fusion of the inner cytoplasm memranes
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Write short notes on the structure of a synapse
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Synapse is composed of non-myelinated presynaptic terminal (expanded axon terminal made up of presynaptic membrane)which contain many mitochondria & synaptic vesicles and postsynaptic terminal made up of synaptic cleft & postsynaptic membrane which contains receptors for the neurotransmitter.
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