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Neuroimmune System
The neuroimmune system is a system of structures and processes involving the biochemical and electrophysiological interactions between the nervous system and immune system which protect neurons from pathogens. It serves to protect neurons against disease by maintaining selectively permeable barriers (e.g., the blood–brain barrier and blood–cerebrospinal fluid barrier), mediating neuroinflammation and wound healing in damaged neurons, and mobilizing host defenses against pathogens. The neuroimmune system and peripheral immune system are structurally distinct. Unlike the peripheral system, the neuroimmune system is composed primarily of glial cells; among all the hematopoietic cells of the immune system, only mast cells are normally present in the neuroimmune system. However, during a neuroimmune response, certain peripheral immune cells are able to cross various blood or fluid–brain barriers in order to respond to pathogens that have entered the brain. For example, there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurodegeneration
A neurodegenerative disease is caused by the progressive loss of neurons, in the process known as neurodegeneration. Neuronal damage may also ultimately result in their cell death, death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, Tauopathy, tauopathies, and prion diseases. Neurodegeneration can be found in the brain at many different levels of neuronal circuitry, ranging from molecular to systemic. Because there is no known way to reverse the progressive degeneration of neurons, these diseases are considered to be incurable; however research has shown that the two major contributing factors to neurodegeneration are oxidative stress and inflammation. Biomedical research has revealed many similarities between these diseases at the subcellular level, including atypical protein assemblies (like proteinopathy) and induced cell death. These similarities su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogen
In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of disease, germ. The term ''pathogen'' came into use in the 1880s. Typically, the term ''pathogen'' is used to describe an ''infectious'' microorganism or agent, such as a virus, bacterium, protozoan, prion, viroid, or fungus. Small animals, such as helminths and insects, can also cause or Transmission (medicine), transmit disease. However, these animals are usually referred to as parasites rather than pathogens. The scientific study of microscopic organisms, including microscopic pathogenic organisms, is called microbiology, while parasitology refers to the scientific study of parasites and the organisms that host them. There are several pathways through which pathogens can invade a host. The principal pathways have different episodic time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut–brain Axis
The gut–brain axis is the two-way biochemical signaling that takes place between the gastrointestinal tract (GI tract) and the central nervous system (CNS). The term "microbiota–gut–brain axis" highlights the role of gut microbiota in these Cell signaling, biochemical signaling. Broadly defined, the gut–brain axis includes the central nervous system, neuroendocrine system, neuroendocrine system, neuroimmune systems, the hypothalamic–pituitary–adrenal axis (HPA axis), Sympathetic nervous system, sympathetic and Parasympathetic nervous system, parasympathetic arms of the autonomic nervous system, the enteric nervous system, vagus nerve, and the gut microbiota. Chemicals released by the Gut microbiota, gut microbiome can influence brain development, starting from birth. A review from 2015 states that the gut microbiome influences the CNS by "regulating brain chemistry and influencing neuro-endocrine systems associated with stress response, anxiety and memory function". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligodendrocytes
Oligodendrocytes (), also known as oligodendroglia, are a type of neuroglia whose main function is to provide the myelin sheath to neuronal axons in the central nervous system (CNS). Myelination gives metabolic support to, and insulates the axons of most vertebrates. A single oligodendrocyte can extend its processes to cover up to 40 axons, that can include multiple adjacent axons. The myelin sheath is segmented along the axon's length at gaps known as the nodes of Ranvier. In the peripheral nervous system the myelination of axons is carried out by Schwann cells. Oligodendrocytes are found exclusively in the CNS, which comprises the brain and spinal cord. They are the most widespread cell lineage, including oligodendrocyte progenitor cells, pre-myelinating cells, and mature myelinating oligodendrocytes in the CNS white matter. Non-myelinating oligodendrocytes are found in the grey matter surrounding and lying next to neuronal cell bodies. They are known as neuronal satellite ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microglia
Microglia are a type of glia, glial cell located throughout the brain and spinal cord of the central nervous system (CNS). Microglia account for about around 5–10% of cells found within the brain. As the resident macrophage cells, they act as the first and main form of active immune defense in the CNS. Microglia originate in the yolk sac under tightly regulated molecular conditions. These cells (and other neuroglia including astrocytes) are distributed in large non-overlapping regions throughout the CNS. Microglia are key cells in overall brain maintenancethey are constantly scavenging the CNS for senile plaques, plaques, damaged or unnecessary neurons and synapses, and infectious agents. Since these processes must be efficient to prevent potentially fatal damage, microglia are extremely sensitive to even small pathological changes in the CNS. This sensitivity is achieved in part by the presence of unique potassium channels that respond to even small changes in extracellular pota ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astrocytes
Astrocytes (from Ancient Greek , , "star" and , , "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cells in the brain and spinal cord. They perform many functions, including biochemical control of endothelial cells that form the blood–brain barrier, provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, regulation of cerebral blood flow, and a role in the repair and Glial scar, scarring process of the brain and spinal cord following infection and traumatic injuries. The proportion of astrocytes in the brain is not well defined; depending on the counting technique used, studies have found that the astrocyte proportion varies by region and ranges from 20% to around 40% of all glia. Another study reports that astrocytes are the most numerous cell type in the brain. Astrocytes are the major source of cholesterol in the central nervous system. Apolipoprotein E transports cholesterol from astrocytes to neuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. Despite being part of the innate immune system, the complement system can be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small, inactive, liver synthesized protein precursors circulating in the blood. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged material, inflammation to attract additional phagocytes, and activation of the cell-killi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T Cell
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface receptor, cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: Cytotoxic T cell, CD8+ "killer" (cytotoxic) and T helper cell, CD4+ "helper" T cells. (These are named for the presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage
Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This self-protection method can be contrasted with that employed by Natural killer cell, Natural Killer cells. This process of engulfment and digestion is called phagocytosis; it acts to defend the host against infection and injury. Macrophages are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adapti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mast Cell
A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a part of the immune and neuroimmune systems. Mast cells were discovered by Friedrich von Recklinghausen and later rediscovered by Paul Ehrlich in 1877. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing, angiogenesis, immune tolerance, defense against pathogens, and vascular permeability in brain tumors. The mast cell is very similar in both appearance and function to the basophil, another type of white blood cell. Although mast cells were once thought to be tissue-resident basophils, it has been shown that the two cells develop from different hematopoietic lineages and thus cannot be the same cells. Structure Mast cells ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoietic Cell
A blood cell (also called a hematopoietic cell, hemocyte, or hematocyte) is a cell produced through hematopoiesis and found mainly in the blood. Major types of blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). Together, these three kinds of blood cells add up to a total 45% of the blood tissue by volume, with the remaining 55% of the volume composed of plasma, the liquid component of blood. Red blood cells Red blood cells or ''erythrocytes'' primarily carry oxygen and collect carbon dioxide through the use of hemoglobin. Hemoglobin is an iron-containing protein that gives red blood cells their color and facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs to be exhaled. Red blood cells are the most abundant cell in the blood, accounting for about 40–45% of its volume. Red blood cells are circular, biconcave, disk-shaped and deformable to allow them to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glial Cells
Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up more than one half the volume of neural tissue in the human body. They maintain homeostasis, form myelin, and provide support and protection for neurons. In the central nervous system, glial cells include oligodendrocytes (that produce myelin), astrocytes, ependymal cells and microglia, and in the peripheral nervous system they include Schwann cells (that produce myelin), and satellite cells. Function They have four main functions: * to surround neurons and hold them in place * to supply nutrients and oxygen to neurons * to insulate one neuron from another * to destroy pathogens and remove dead neurons. They also play a role in neurotransmission and synaptic connections, and in physiological processes such as breathing. While glia wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
