Test Your Knowledge on Neuron Anatomy

Anatomy of Neurons

• Nervous tissue is composed of closely packed cells and has two principal types of cells: neurons and glial cells.
• Neurons are the functional and structural unit of the nervous system and exhibit irritability and conductivity.
• There are three general categories of neurons: sensory, motor, and interneurons.
• Sensory neurons convey impulses from receptors to the CNS and can be somatic or visceral afferent fibers.
• Motor neurons convey impulses from the CNS or ganglia to effector cells and can be somatic efferent or visceral efferent neurons.
• Interneurons form a communicating and integrating network between the sensory and motor neurons and make up more than 99.9% of all neurons.
• Neurons have a cell body (perikaryon) that contains the nucleus surrounded by basophilic cytoplasm (neuroplasm) and enclosed by a cell membrane (neurolemma).
• Neurons have processes, including axons and dendrites.
• Axons transmit impulses away from the cell body to a specialized terminal (synapse), while dendrites transmit impulses from the periphery toward the cell body.
• Neurons can be classified based on the number of processes extending from the cell body: multipolar, bipolar, and pseudounipolar or unipolar.
• The perikaryon has characteristics of a protein-producing cell and contains Nissl bodies (stacks of rough endoplasmic reticulum) and a Golgi complex.
• The cytoskeleton of neurons is formed by three types of neurofibrils: microfilaments, intermediate filaments or neurofilaments, and microtubules.