6 topics with concise breakdowns: definitions, key facts, and class questions.
Nervous tissue is the most complex and highly specialized system of the body. In this section, we analyze its morphology, from the stages of embryonic development originating from the neural tube to the ultrastructure of mature cells.
You will study the structure of neurons, their morphological classification, and the mechanisms of axonal transport, which are essential for cell survival and signal transmission. Special attention is paid to neuroglia—the supportive and trophic apparatus of the nervous system—as well as the principles of formation of myelinated and unmyelinated nerve fibers.
During colloquiums and exams, professors most frequently ask about the differences between astrocytes and oligodendrocytes, the process of myelination in the CNS and peripheral nerves, and ask you to explain the essence of retrograde and anterograde axonal transport. Master this foundation now—it will save you time and effort repeatedly in physiology, neuroanatomy, and clinical neurology.
What is the embryonic origin of the nervous system?
The primary ectoderm is the sole source of development for the nervous tissue and the entire nervous system. The process of anlage formation (neurulation) is initiated under the inductive influence of the notochord.
How to distinguish an axon from a dendrite in a tissue preparation stained with Nissl stain?
In the axon and its site of origin (axon hillock), the basophilic substance (Nissl bodies) is completely absent. In dendrites and the perikaryon itself, the tigroid substance is clearly visualized.
Why is microglia singled out among other gliocytes?
Microglia is the only type of glia having a mesenchymal (monocytic) origin. All other glial cells develop from neural glioblasts.
What is the essence of saltatory impulse conduction?
This is the saltatory propagation of a nerve signal in myelinated fibers. Due to the myelin insulation, the impulse jumps between the nodes of Ranvier, which significantly increases transmission speed.
Where are sodium channels localized in a myelinated nerve fiber?
In myelinated fibers, voltage-gated sodium channels are concentrated exclusively in the region of the nodes of Ranvier, whereas the regions beneath the myelin are virtually unexcitable.
Master the entire topic in the "Histology" course
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