Question

The characteristic features to identify a nerve cell are:
A. Cell body with branched cytoplasmic extensions at one end and long projections at the other end.
B. Rounded or oval cells with bilobed nucleus and cytoplasmic granules.
C. Spindle shaped cell with a big central nucleus.
D. Red coloured, biconcave disc shaped, enucleated cells.

Answer 1

Hint:- A nerve cell, commonly known as neuron, is present in the region of brain and spinal cord, and is the main constituent of the nervous tissue. It excites electrically, and so communicates with other cells through synapses, which is a special connection between cells.

Complete step-by-step solution:- Nerve cells generate electrical signals (sparks) when they get excited and send these electrical sparks throughout our body that transmit signals. This is a part of the nervous system, which is a complex system that conveys electrical messages throughout our body. The electrical signals transmitted between cells are called nerve impulses.
Neurons are the basic (structural and functional) units of the nervous system.
Neurons have three parts:
cell body, dendrites, and axon. The cell body has a prominent nucleus and other cell organelles present in it. Dendrites are branch-like structures extending out from the cell body that transmit nerve impulses. The axon is a long extended fibre which has branches at its distal end that forms axon terminals. Thus an overall structure of a nerve cell looks like a cell with the cell body at one end having branched cytoplasmic extensions and at the other end, long projections.
So the correct option is (A).

Additional Information: There are three types of nerve cells or neurons: Sensory neurons, Motor neurons, and Interneurons. Sensory neurons are a part of the nervous system that carries nerve impulses to the brain and spinal cord from all the parts of the body. On the other hand, Motor neurons carry signals from the spinal cord and brain to all the body parts (muscles, tissues and glands). Interneurons are the connections that carry signals between sensory and motor neurons in both the directions.

Note:- Nerve cell is present in all the animals except sponges and placozoa. However, it is absent in fungi and all the plants. The signals transmitted by the nerve cells are very quick and thus organisms react to any stimuli within seconds.