Question

The glial cells which help in providing a blood-brain barrier are
(a) Astrocytes
(b) Ependymal cells
(c) Microglial cells
(d) Oligodendrocytes

Answer 1

Hint: The nervous system is composed of neurons and glial cells. Neurons respond to physical or chemical stimuli while glial cells support, nourish, and protect the neurons. The glial cells which help in providing a blood-brain barrier are star-shaped and keep a check on materials entering or exiting the CNS.

Complete answer:
Astrocytes are star-shaped due to the many cytoplasmic processes or extensions extending from their main cell body. These extensions are necessary for them to interact with the neurons, blood vessels, or any connective tissue in the CNS. Their main function is contributing to the blood-brain barrier in the brain. This barrier as the name suggests snake sure that only the important required molecules like glucose or amino acids can cross into the CNS while restricting the rest. They also help in regulating the external environment of neurons in the CNS.

Additional Information: -Neuroglia or simply glial cells make up about half the volume of the CNS. they are smaller than the neurons but more numerous. They do not generate any action potential. But unlike neurons, they can multiply and divide in the mature system. Thus, during any injury or disease, they multiply to fill in the spaces formerly occupied by the neurons.
-Ependymal cells have a tear-shaped body. They possess a long tail, at whose end, many branches arise which connect with fellow astrocytes and neurons. They line the ventricles of the brain and central canal of the spinal cord and participate in the production of cerebrospinal fluid.
-Microglial cells keep migrating through the CNS in order to catch a phagocytose of any foreign organism that may have migrated into the CNS.
-Oligodendrocytes are responsible for providing a myelin sheath to the axons of multiple neurons at a time. Myelin sheath is present in myelinated neurons and accounts for the greater speed of impulse traveling along an axon.
So, the correct answer is ‘Astrocytes.’

Note: -A neuron consists of a cell body, from which many cytoplasmic processes or extensions arise which are of two kinds: multiple dendrites and a single axon.
-Cell body is also known as soma or cyton. It consists of neoplasm, nucleus, and cell membrane along with organelles such as the Golgi apparatus, lysosomes, neurofibrils, and Nissl’s granules.
-Dendrites are usually shorter, and highly branched extensions arising from the cell body and receive impulses from other neurons. An axon is a long, thin, cylindrical portion that propagates the nerve impulse to another neuron, muscle fiber, or a gland cell.