Question

answer the questions below:

4. Explain the general structure of a neuron and name its important anatomical regions?

5. Explain the composition of gray matter and white matter?

6. Explain the functional and structural classification of neurons ?

7. Exuthe events that lead to the generation of nerve impulse and its conduction from one neuron to another?

8. Define reflex arc & its elements and give typical example?

plz l want to more explain for these questions (plz)

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Answer 1

4. Neurons are electrically excitable cells that are involved in communication in higher animals. Plants, fungi, sponges, and placozoa do not possess nerve cells. Neurons are terminally differentiated cells and generally do not exhibit proliferation ability.
A typical nerve cell contains three parts.
1. Cell body (Soma)
2. Dendrites
3. Axon
The cell body is a compact structure that contains the nucleus and other cell organelles. Dendrites and axon are filamentous extensions. Dendrites are small filamentous projections that radiate from the soma. The axon is a longer filamentous structure that leaves the soma at axon hillock. It branches out at its farthest tip to produce axon terminals. The axon is covered by myelin sheath that serves as an insulator.

5. The grey matter contains relatively few myelinated axons and many cell bodies.
It also contains neuropil , axon tracts, capillary blood vessels, and glial cells.
It constitues 40% of the brain.
It serevs to process information.

The white matter contains relatively few cell bodies and many long-range myelinated axons.
It also contains astrocytes and oligodendrocytes
It constitues 60% of the brain.
It allows communication to and from grey matter

6. Structural classification of neurons:
a. Unipolar neurons
b. Bipolar neurons
c. Multipolar neurons

Functional classification of neurons:
a. Sensory neurons
b. Motor neurons
c. Interneurons