Neuroanatomical Guide

Introduction

The human nervous system refers to an extremely reliable, efficient, compact and fast computing system. Practically, this system can outperform a computer that has ever been made by man. The general structure or the anatomy of the nervous system is what is referred to as the Neuroanatomy. Neuroanatomy is merely a study of the organization and structure of the nervous system. It is a system that makes it possible to communicate, feel, move, think or even experience emotions. This guide aims to explain the basic neuroanatomical structures, functions, location and the interaction between the structures. With an appropriate utilization of pictures and graphics, the guide seeks to elucidate the basic neuroanatomical structures in layman’s language. 

Basic Neuroanatomy

The neuroanatomy, or merely the anatomy of the nervous system is subdivided into two compartments; the peripheral nervous system (PNS) and the central nervous system (CNS). The central nervous system (CNS) consists of the spinal cord, the brainstem, and the brain (Patestas, & Gartner, 2016). The peripheral nervous system (PNS) includes everything else including the muscles, peripheral nerves, and neuromuscular junctions. The above description represents the morphological subdivision of the nervous system. The functionality subdivision of the nervous system includes the somatic and the autonomic nervous system. The somatic nervous system is under the conscious control of an individual while the autonomic nervous system controls some activities alongside the voluntary nervous system (Parrish, 2015). 

A simple understanding of the two components is that; the brain represents the anatomical structure while physiological structure (functional) is described by the mind. The brain can be understood as the computer hardware while the mind is the software of a computer. In summary, the Neuroanatomy refers to the scientific study of the spinal cord, the brain, spinal nerves, dermatomes, cranial nerves, joints, and muscles (Parrish, 2015). Even though the term neuroanatomy seems to be a complicated concept to understand, it is interesting and easy to comprehend. 

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The Central Nervous System (CNS)

The central nervous system majorly controls most of the functions of the body and the mind. There are two major parts of the CNS namely; the brain and the spinal cord (Nieuwenhuys, Hans, & Nicholson, 2014). The brain usually functions as the center of thoughts, interprets the surrounding or the environment, and regulates body movement. Just like computer functions, the brain interprets information received from the eyes (sight), tongue (taste), skin (touch), nose (smell) and ears (sound). The human brain is recognized as the command center for the nervous system. Input from the sensory nerves is received by the brain, and then it is sent to the muscles as output (Patestas, & Gartner, 2016). The cerebrum is the largest part of the human brain and is composed of two major hemispheres. The cerebellum sits behind it while the brainstem lies underneath. The cerebrum’s outer layer is called cerebral cortex (Parrish, 2015). The cerebral cortex is made up of the occipital lobe, the frontal lobe, the temporal lobe and the parietal lobe. The brainstem is made up of the midbrain, pons and the medulla oblongata. The main function of the brainstem is to relay information between the body and the brain, control breathing, heart, and consciousness, and supply cranial nerves to the head and the face. 

The front half of the CNS controls and organizes the movement while the back half of the CNS usually receives and processes the information received from the senses. There is a hierarchical organization of the CNS. This kind of hierarchical organization has layers/layers where each level controls the subsequent levels (Parrish, 2015). This kind of organization follows the analogy of the military where the highest rank is general (general>colonel>major>lieutenant). 

The Peripheral Neural System (PNS)

The PNS entails all the nerves present outside the spinal cord and the brain. Nerves can refer to the bundles of axons or neuron fibers that normally carry information in a structure. The nerves that link sensory receptors and skeletal muscles are called the somatic nervous system (Chandran et al. 2016).  There are afferent nerves whose purpose is to transfer information to the spinal cord. On the other hand, the efferent fibers usually convey the neural impulses away from the spinal cord (central nervous system). The autonomic nervous system is composed of parasympathetic division and sympathetic division (Patestas, & Gartner, 2016). Significant physiological arousal such as tremor, sweat or rapid heartbeat is mediated by this system especially when an individual experiences an emergency or a fearful situation. The sympathetic nervous system is responsible for emergency responses while the parasympathetic is responsible for energy conservation in the body. It is the role of this system to regulate normal operations of the body such as heart rate, digestion, and blood pressure. 

The Rationale of Neuroanatomy for Diagnosis

Some diseases usually affect the peripheral or the central nervous system and thus causing specific symptoms such as mental impairment, sensory deficits, and reduced consciousness level. Circumscribed lesions can cause certain disorders such as tumors, vascular occlusions, and localized infections. In most cases, functions that have been assigned to a certain part of the brain are normally found disordered illustrating that the site has been destructive or irritating (Parrish, 2015). Diseases related to the spinal cord are usually caused by major interruption especially of the functional pathway. Knowledge of neuroanatomy is essential in any clinical setup. It assists in defining Clinicopathological correlations to deduce the inherent problem for a clear pathological finding. 

References

Anatomy And Function Of Brain Stem Made Easy Brainstem Neuroanatomy – heritance.me. (2018). Retrieved from http://heritance.me/anatomy-and-function-of-brain- stem/anatomy-and-function-of-brain-stem-made-easy-brainstem-neuroanatomy

Chandran, V., Coppola, G., Nawabi, H., Omura, T., Versano, R., Huebner, E. A., … & Blesch, A. (2016). A systems-level analysis of the peripheral nerve intrinsic axonal growth program. Neuron, 89(5), 956-970.

Nieuwenhuys, R., Hans, J., & Nicholson, C. (2014). The central nervous system of vertebrates. Springer.

Parrish, R. (2015). Basic Neuro Anatomy. In Comprehensive Guide to Neurosurgical Conditions (pp. 1-5). Springer, Cham.

Patestas, M. A., & Gartner, L. P. (2016). A textbook of neuroanatomy. John Wiley & Sons.