Chapter 16, Problem 1.1BGL

Summary Introduction

The nervous system is composed of two components, which includes the central nervous system and the peripheral nervous system. The central nervous system includes the brain and the spinal cord, whereas the peripheral nervous system includes the motor and the sensory receptors. The brain is composed of nerve tissues that are protected within the skull. The major functions of the brain include processing sensory information, releasing hormones, and regulating blood pressure and breathing.

Answer to Problem 1.1BGL

Explanation of Solution

Schwann cell:

The Schwann cell is a glial cell that plays an important role in supporting the PNS. The Schwann cell, also termed as neurilemma cell, is a type of nervous tissue cell in PNS involved in producing the myelin sheath around the neuronal axons and also helps in regenerating the axons.

Ependymal cell:

The ependymal cell is a neuronal support cell, known as neuroglia, which forms the epithelial lining of the ventricles present in the brain and also the central canal of the spinal cord. Moreover, the ependymal cells give rise to the epithelial layer that encircles the choroid plexus. The choroid plexus is a collection of blood vessels that exist in the lateral ventricle walls. Cilia, present in the ventricles of the ependymal cell, help in influencing the cerebrospinal fluid direction and also bring nutrients and other substances to the neuron.

Microglia:

Microglia is a type of neuroglial cell that supports the CNS as it functions as an immune cell. The microglial cell is the smallest cell of all the neuroglia. Its main role is to mediate the immune response in the CNS by acting as macrophage, removing dead neurons, and cellular debris from the nervous tissue through the phagocytosis process.

Astrocytes:

Astrocytes, also termed as astroglia, which is characterized by star-shaped glial cells present in the brain and the spinal cord. It performs numerous functions, like axon guidance, synaptic support, controls blood-brain barrier, and also controls the blood flow. In addition, astrocytes are majorly responsible for homeostasis of the CNS.

Satellite cell:

The satellite cell, also termed as muscle stem cell or myosatellite cell, is a multipotent, flattened cell that usually exists in the ganglia (sympathetic ganglia, parasympathetic ganglia, and sensory ganglia) of the PNS. It encompasses a small amount of cytoplasm present in the mature muscle. The satellite cell plays a major role in regulating and stabilizing the environment around ganglion cell bodies.

Oligodendrocytes:

Oligodendrocyte is a type of neuroglia that supports the CNS by providing support and insulation to axons. The oligodendrocytes create an isolating sheath around the axons for rapid conduction of the signal. This may lead to massive conduction of electrical signals inside the axon.