Question

Draw the structure of a neuron and explain its function.

Answer 1

Neurons:

1. The neuron is the structural and functional unit of the nervous system.
2. Neurons are capable of detecting, receiving, and transmitting a variety of inputs.
3. The three major parts of this microscopic structure are the cell body (soma), dendrites, and axons.

Cell body (soma):

1. Cytoplasm, cell organelles, and Nissl's granules are all found in the cell body.
2. The cell body preserves the structural integrity of the neuron, houses the genetic material, and supplies energy to drive activities.

Dendrites:

1. Dendrites are short fibers that branch out from the cell body repeatedly and include Nissl's granules as well.
2. Dendrites transmit impulses toward the cell body.

Axons:

1. The axon is a branching fiber with a long distal end.
2. Each branch ends in a synaptic knob, a bulb-like structure that houses synaptic vesicles that contain neurotransmitter molecules.
3. Nerve impulses are transmitted from the cell body to a synapse or a neuromuscular junction through axons.
4. Neurons can be unipolar, bipolar, or multipolar, depending on the number of axons and dendrites.
5. Axons come in two varieties: myelinated and non-myelinated.
6. Schwann cells surround the myelinated nerve fibers, creating a myelin sheath around the axon.
7. Nodes of Ranvier are the spaces between two neighboring myelin sheaths.