Neurons+and+Glia

__Neurons and Glia __

Neurons and Glia are the cells in the nervous system. The components and origzation of the nervous system was a major debate among scientist in the 19th century. And this developed the Neuron Doctrin and Reticular Theory. Joseph Von Geralch is distinguished as establishing the reticulum theorem. Johannes Evangelista Purkinje was the first person to investigate nervous tissue in a compound microscope.

A neuron, or nerve cells are the foundation of the nervous system, which includes the Central Nervous System and the Peripheral Nervous System. Neurons process and transmit information throughout the body from electrochemical signals. They are catalogued based on their specified functions. Afferent or Senory Neurons are responsible for transmitting information from sensing signals themselves or from signals received from sensory receptors located in the skin, eyes, nose, tongue, and ears towards the CNS, which includes the brain and spinal cord. Efferent Neurons, or motor neurons, receive electrochemical signals from the brain and are responsible for transmitting that information away from the CNS to the muscle and glands and causes muscle contractions and glandular outputs. And lastly, Interneurons, which are able to send information between the sensory neurons Afferent and Efferent neurons and connect neurons in the same region of the brain or spinal cord. Typical neurons are composed of a soma (cell body), dendrites, and axons. Dendrites are thin structures, visualized as branched projection, extending and branching numerous times. The dendrites are accountable for conducting electrochemical impulses received from the neural cells to the soma of the neuron. The electrochemical stimulation is relayed onto the dendrites by axons via synapses. Axons are observed as a thin cord and are in charge of transmitting electrochemical impulses away from the soma to different neurons, muscles, and glands. Figure two depicts a visualization of the typical neuron. [1]

Glia or neuroglia are non-neuronal cells that play a vital role to the neurons. Their importance to neurons includes surrounding and insulating the neurons, supplying them oxygen and necessary nutrients, destroying pathogens that may harm them, and eliminating dead neurons. There are several types of glial cells which are located in the CNS and PNS. These different types of glial cells include, microglia cells, astrocytes, oligodendrocytes, ependymal cells, Schwann cells, and satellite cells. Microglia protects the neurons from pathogens from bacteria. Astrocytes assist the neurons in creating the blood-brain barrier in order to protect the CNS from harmful chemicals. Oligodendrocytes make myelin for insulation and protection of neurons and also the regulation of speed at which neurons transmit electrochemical impulses. Ependymal cells creates cerebrospinal fluid that cushions the CNS. Schwann cells create myelin around axons too, but for the PNS and assist in regeneration of damaged axons. And Satellite cells moderate exchange of materials between neurons and fluid in the PNS [1]. Figure Three depicts visualizations of the neurons and glial cells of the nervous system.

One disease that is associated with neurons and glia is Multiple Sclerosis. Multiple Sclerosis is an immune-mediated disease which attacks the central nervous system. This attack causes damage to the neurons and to the myelin sheath which is the substance that surrounds the neurons for protection. This destruction causes the electrochemical nerve impulses that are traveled to and from the brain by neurons to be distorted, thus resulting in a wide-range of diverse symptoms. Symptoms include any neurological sign or symptom, may be mild or severe and may cause physical and mental problems within the patient. Figure Four depicts signs and symptoms of Multiple Sclerosis. The cause for this disease is currently still unknown but may consist of both genetic and environmental factors. Currently no known cure for this disease exists either, only treatments to attempt to hinder new attacks and to enhance functions after attacks. Everyone inhibiting this disease is affected in their own individual way [2].

Research Articles: Article # 1: This article outlines research done by Dr. Robert Lisak and Dr.Joyce Benjamins. This research encapsulates the effects of secretory products of immune cells on nerons and glia. By analyzing cytokine-induced changes in gene expression in CNS glial cultures the researchers were able to categorize a series of changes in immune-related molecules, neurotrophins, growth factors, and structural proteins, and also molecules metabolism, signaling, and structure. This article revealed that responses of neurons to cytokines were less than the responses of glia to cytokines, suggesting that glial cells are the first in reciprocating inflammatory signals. This article also discussing MS. [2] Article # 2: This article provides insight of the importance of noncoding microRNAs (miRNAS) in determining the fate of neurons and glial cells which is an important factor in neural development and function. This article provides evidence that microRNAs play a role in establishment of neuronal subtypes which is obtained through microRNA gene expression. This article, also through microRNA gene expression, revealed that microRNA regulates glial development as well. [3] Article # 3: This article analyzes a study of Reservatrol, which is a supplement that is hypothesized in having neuroproductive properties. These beneficial properties are seen in conditions where neurodegeneration was caused by disease and injury, as opposed as a result of aging. This study provides clear evidence that neurodegeneration caused by aging is due to the degeneration of the neuron and glia and the Reservatrol does not preserve neurons. [4] __References __ [1] Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., & Walter, P. (2008). //Molecular Biology of THE CELL.// New York : Garland Science, Taylor & Francis Group. [2] Benjamins, J. A. (2013). Direct effects of secretory products of immune cells on neurons and glia. //Journal of the Neurological Sciences, 333//(1–2), 30-36. [3] Bian, S., Xu, T., & Sun, T. (2013). Tuning the cell fate of neurons and glia by microRNAs. //Current Opinion in Neurobiology, 23//(6), 928-934. [4] Genade, T., & Lang, D. M. (2013). Resveratrol extends lifespan and preserves glia but not neurons of the nothobranchius guentheri optic tectum. //Experimental Gerontology,48//(2), 202-212.

Gina Ghianni