Question

The most appropriate definition of neuroglial cells are that they are
A. Nonsensory supporting cells
B. Secretory cells
C. Sensory cells
D. Sensory and supporting cells

Answer 1

Hint: Neurons and neuroglial cells lie side-by-side and there are no direct junctions, such as gap junctions, between them. Gap junctions do exist between neuroglial cells.

Complete Answer:
- Glia, also called glial cells or neuroglia, are non-neuronal cells in the central nervous system (brain and spinal cord) and the peripheral nervous system that do not produce electrical impulses. In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells, and microglia, and in the peripheral nervous system glial cells include Schwann cells and satellite cells.
- Astrocytes support the neurons and anchor them to their nutrient supply lines. They also have an important role in making exchanges between capillaries and neurons.
- Microglial cells can transform into a special type of macrophage, which can clear up the neuronal debris. They also monitor the health of the neuron.
- Ependymal cells line the ventricles of the CNS and help to circulate the cerebrospinal fluid (CSF).
- Oligodendrocytes cells produce an insulating covering called myelin sheath around the fibers.
- Schwann cells have similar functions like oligodendrocytes and microglial cells. It provides myelination to the PNS and has phagocytic activity.
- Satellite cells perform a similar function to astrocytes. They are very sensitive to injury and inflammation, and seem to contribute to pathological states, such as chronic pain.
- Neuroglial cells have four major functions: to hold the neurons in place; to supply nutrients and oxygen to neurons; to cover one neuron from another; to destroy pathogens and remove dead neurons.
- Neuroglia is present in the nervous systems of invertebrates as well as vertebrates and can be distinguished from neurons by their lack of axons and the presence of only one type of process. They also do not form synapses, and they retain the ability to divide throughout their lifespan.

Hence, from the above points, we can conclude that the correct answer is option A, ‘Nonsensory supporting cells’.

Note: The Italian biologist Emilio Lugaro proposed that neuroglial cells exchange substances with the extracellular fluid and by this exert control on the neuronal environment. For example, after high levels of neuronal activity, neuroglial cells can take up and spatially buffer potassium ions and thus maintain normal neuronal function.