Nervous System
The nervous system is one of the most important systems of the human body, and its study is a process that requires a comprehensive analysis of its functions. This system consists of the CNS and PNS, which, in turn, consist of the brain and spinal cord, as well as nerves and ganglia, respectively. The structure of the nerve cell includes the body and fibers. The nervous system provides interconnected regulation of the activity of all systems of the body and the response to changes in the conditions of the internal and external environment.
Brain
The human brain is one of the most complex organs that determine the functioning of all body systems and controls biochemical processes. Electrical impulses arising from specific actions determine the nature of behavior and are controlled by consciousness. Interneural connections serve as the main mechanism for storing and processing information and determine the level of consciousness and intellectual development. Due to the complexity of its structure and internal processes, the brain makes it possible to accumulate information, process it, and transform it based on individual experience.
Anatomical Location
The human brain occupies a large part of the cranium and is a relatively large organ. It is located superior to the spinal cord and is a continuation of it. The brainstem is centered on the main body of the brain. As it grows, the brain transforms and takes the shape of a skull. The size of the brain is directly proportional to a person’s age, but its location in the skull remains unchanged. The organ is superior to all the other parts of the nervous system.
Anatomical Description
The structure of the brain is complex and includes three sections: the cerebral hemispheres (left and right), the brainstem, and the cerebellum. Each of these sections can be subdivided into smaller parts that carry out individual functions. Processes inside the brain are impulses that travel along nerve fibers and define the nature of biochemical processes in the body. The level of consciousness and the specifics of actions performed by a particular person determine at what level the activity of the brain is noted and what its type is. The cerebral hemispheres are the biggest part of the brain and include several structures.
Cortex
This sinuous layer of tissue is the outer surface of the cerebral hemispheres. It consists of a thin layer of gray matter and contains most of the nerve cells in the nervous system.
White matter
White matter is made up of nerve fibers that connect nerve cells in the cerebral cortex to one another and to other parts of the brain and spinal cord.
Subcortical structures
These structures are located under the cerebral cortex and include the basal ganglia, thalamus, hypothalamus, hippocampus, and limbic system.
In addition to the large cerebral lobes, there are other structural elements of this organ. The brainstem serves as a link to the spinal cord and is responsible for vital functions. The cerebellum, located above the spinal cord, receives information from the cerebral cortex and basal ganglia. For protection, the brain and spinal cord have special membranes that form three layers: the dura, arachnoid, and pia maters. Finally, cerebrospinal fluid is a conduit between the brain and the spinal cord and serves as a channel for the removal of waste products from tissues, mainly protein structures.
Cells and Tissues
The multicellular structure of the brain includes various elements that form intracerebral connections. The neural system is developed and functions due to electrical impulses that neurons exchange through synapses. Glial cells are located in the white matter and serve as auxiliary elements for neurons by providing a stable supply of nerve impulses and maintaining neuronal activity. In addition, they absorb the cerebrospinal fluid and fill all internal spaces of the brain with it. Astrocytes, as nerve tissue cells, are located around neurons and synapses and help the latter to transmit impulses better.
The gray matter of the brain consists mainly of clusters of nerve cells and the nearest branches of their processes. The white matter of the brain includes clusters of nerve fibers, which are processes of nerve cells that have a myelin sheath. Nerve fibers form the pathways of the brain and connect the various parts and nuclei of the central nervous system. The nerve fibers of the white matter of the cerebral hemispheres are divided into three groups: associative, commissural, and projection.
Functions of the Brain
The brain is the key organ of the nervous system, which controls not only physical but also cognitive processes. Due to the work of its individual structural elements, a person is able to accumulate and transform the information received, which is the basic ability of memory. Any signals from the senses go to the brain that, in turn, interprets them and sends appropriate impulses forming biochemical reactions. One of the main properties is the ability to generate lucid speech. The coordination of movements is also controlled by the brain, and a person can move straight and not lose orientation in space.
Hemispheres
The hemispheres of the brain control two sides of the body, while each of them controls the opposite side. In the cerebral lobes, the main centers of the perception and processing of sensory information are concentrated – sight, smell, hearing, touch, taste, as well as speech. Both hemispheres have the function of controlling conditioned reflexes and forming human cognitive abilities. Due to their work, the perception of data entering the brain is converted into a coherent flow of information and can be generated and accumulated.
Hypothalamus
The hypothalamus is included in the intermediate region of the brain and is one of its two structural parts, along with the thalamus. Control over the processes of energy homeostasis is one of the main functions of the hypothalamus. This part of the brain is involved in regulating metabolism and supplies the brain with information about the body’s nutritional needs. In addition, the hypothalamus is the part of the brain that coordinates the cardiovascular system and digestion, which would explain its role in regulating nutritional needs. Another significant function is the control over the phases of wakefulness and sleep. The hypothalamus contains small-cell and large-cell neurons, and the endocrine system is controlled due to the interaction with the pituitary gland.
Thalamus
The functions of the thalamus are no less important than those of the hypothalamus. This component of the intermediate part of the brain plays the role of a transformer that is connected to the hemispheres and receives all information from external stimuli. The data is filtered, which allows for responding to specific processes adequately. In conditions of any changes that occur, for instance, a decrease in temperature or fluctuations of light waves, the thalamus is the main component of the brain that receives this information and transmits it to the parts of the hemispheres.
Cerebellum
The cerebellum is an important part of the posterior region of the brain. The coordination of movements, whether slow or fast purposeful movements, is carried out due to this brain component. In addition, the cerebellum has the function of controlling muscle tone and distributing the tension of individual muscles depending on the type of load. Autonomic reflexes that involve unconscious responses, such as the constriction of the pupils when exposed to light or increased blood pressure, are also dependent on the cerebellum.
Homeostasis
Due to the hypothalamus as one of the important components of the brain, homeostasis in the body is maintained. In particular, the body’s ability to respond to temperature changes depends on how productive this organ is. The release of hormones into the blood as a result of impulses received from the hypothalamus makes it possible to activate additional organs that, in turn, start the necessary processes. The thyroid gland connected to the hypothalamus triggers heat production, while the adrenal glands have the function of reducing heat transfer and helping retain heat in the body.
Prediction
The dysfunction of the hypothalamus is fraught with a threat to homeostasis and can be fatal. Two potentially dangerous outcomes are overheating of the body or, conversely, hypothermia. If the hypothalamus cannot control how much heat the body needs, the risk of overheating increases. As a result, cells die when exposed to a high temperature. In hypothermia, the hypothalamus does not interact with the thyroid gland and adrenal glands, thereby inhibiting the process of controlling heat transfer, and in this case, the organs cease to function due to the cold.
Brain Diseases
As one of the possible diseases of the brain, one can mention atherosclerosis of cerebral vessels. This illness is caused by various reasons, for instance, a genetic predisposition, a high cholesterol level, or bad habits, and leads to the accumulation of lipid plaques on the walls of blood vessels. Blood flow deteriorates, which, in turn, is fraught with numerous problems due to impaired brain function and the lack of nutrients entering its individual parts. A variety of cognitive and physical impairments are observed, including problems with coordination, sleep, heat regulation, and other dangerous health issues.
References
Aberg, K. C., Doell, K. C., & Schwartz, S. (2017). The “creative right brain” revisited: Individual creativity and associative priming in the right hemisphere relate to hemispheric asymmetries in reward brain function. Cerebral Cortex, 27(10), 4946-4959. Web.
Casillo, S. M., Luy, D. D., & Goldschmidt, E. (2020). A history of the lobes of the brain. World Neurosurgery, 134, 353-360. Web.
Chu, C., Zhong, G., & Li, H. (2020). Structure and function of subcortical periodic cytoskeleton throughout the nervous system. STEMedicine, 1(1), e9. Web.
Fukutomi, H., Glasser, M. F., Zhang, H., Autio, J. A., Coalson, T. S., Okada, T., Togashi, K., Van Essen, D. C., & Hayashi, T. (2018). Neurite imaging reveals microstructural variations in human cerebral cortical gray matter. Neuroimage, 182, 488-499. Web.
Kasinathan, V., Mustapha, A., Abidin, A. Z. Z., & Fajrillah, A. A. N. (2018). Three-dimensional e-learning application for anatomy and physiology of brain. International Journal of Integrated Engineering, 10(6), 144-148. Web.
Li, B., Lu, X., Moeini, M., Sakadžić, S., Thorin, E., & Lesage, F. (2019). Atherosclerosis is associated with a decrease in cerebral microvascular blood flow and tissue oxygenation. PloS One, 14(8), e0221547. Web.
Mehani, B., Narta, K., Paul, D., Raj, A., Kumar, D., Sharma, A., Kaurani, L., Nayak, L., Dash, D., Suri, A., Sarkar, C., & Mukhopadhyay, A. (2020). Fusion transcripts in normal human cortex increase with age and show distinct genomic features for single cells and tissues. Scientific Reports, 10(1), 1-12. Web.
Nakagawa, Y. (2019). Development of the thalamus: From early patterning to regulation of cortical functions. Wiley Interdisciplinary Reviews: Developmental Biology, 8(5), e345. Web.
Nowinski, W. L., & Thaung, T. S. (2018). A 3D stereotactic atlas of the adult human skull base. Brain Informatics, 5(2), 1-9. Web.
Salman, M. S., & Tsai, P. (2016). The role of the pediatric cerebellum in motor functions, cognition and behavior: A clinical perspective. Neuroimaging Clinics of North America, 26(3), 317-329. Web.
Yoo, S., & Blackshaw, S. (2018). Regulation and function of neurogenesis in the adult mammalian hypothalamus. Progress in Neurobiology, 170, 53-66. Web.