UNIT QUIZ: Critical Thinking and Application Questions Neurons are amitotic, whi
ID: 3509700 • Letter: U
Question
UNIT QUIZ: Critical Thinking and Application Questions Neurons are amitotic, which means that art amitotic, which means that after a certain stage, they do not divide further. Cancerous cells are charact by a rapid rate of mitosis. Considering this, of which cell types (neurons or neuroglia) must brain te Why? puld you expect to see synaptic vesicles in dendrites? Why or why not? (Hint: Consider the functions of dendrit versus axons.) 3 A traumatic brain injury may result in a large number of damaged or dying neurons. In such a case, which neuro would you expect to be present in large numbers? Explain. 4 Multiple sclerosis is a demyelinating disease, in which the patient's immune system attacks and destroys the mye sheath in the central nervous system. What types of symptoms would you expect from such a disease? Why? W Schwann cells or oligodendrocytes be affected? Explain.Explanation / Answer
Answer :
1) The neurons are the fundamental units of the nervous system. They are fully differentiated(matured) postmitotic cells which do not enter into the cell division stage. In the cell cycle, they are said to be in the G0 Phase(of the interphase) or the quiescent phase and do not divide any further. Also, they lack an important organelle for cell division, the centrosomes.
So, Most commonly, Tumors of the brain arise from the glial cells which are the supportive cells of the brain and rarely from the neurons themselves. Glial cells are of three types; Astrocytes, Oligodendrocytes and Ependymal cells. Some tumors of the brain are: Astrocytoma, oligodendrogliomas, ependymomas, meningiomas etc.
2) No. Synaptic vesicles are not seen in dendrites.
A neuron has a cell body called the soma, the axon which is a long process and dendrites which are short branches arising from the soma. The axons carry signals from the cell towards another neuronal dendrite. A synapse is formed at the junction of the axon and the dendrite; where at the axonal ends, vesicles release neurotransmitters into the synaptic cleft which are taken up by the receptors on the dendrites of the neighboring neuron and further transmitted to the next neuron propagating the signal. It is a one-way transmission only which occurs from the axons to dendrites of the adjacent neuron.
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