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Mucosa-associated Lymphoid Tissue
The mucosa-associated lymphoid tissue (MALT), also called mucosa-associated lymphatic tissue, is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasopharynx, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue. MALT constitute about 50% of the lymphoid tissue in human body. Immune responses that occur at mucous membranes are studied by mucosal immunology. Categorization The components of MALT are sometimes subdivided into the following: * GALT (gut-associated lymphoid tissue. Peyer's patches are a component of GALT found in the lining of the small in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphatic System
The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid organs, and lymphoid tissues. The vessels carry a clear fluid called lymph (the Latin word ''lympha'' refers to the deity of fresh water, "Lympha") back towards the heart, for re-circulation. Unlike the circulatory system that is a closed system, the lymphatic system is open. The human circulatory system processes an average of 20 litres of blood per day through capillary filtration, which removes plasma from the blood. Roughly 17 litres of the filtered blood is reabsorbed directly into the blood vessels, while the remaining three litres are left in the interstitial fluid. One of the main functions of the lymphatic system is to provide an accessory return route to the blood for the surplus three litres. The other main function is that of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immune Response
An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could cause serious problems to the health of the host organism if not cleared from the body. There are two distinct aspects of the immune response, the innate and the adaptive, which work together to protect against pathogens. The innate branch—the body's first reaction to an invader—is known to be a non-specific and quick response to any sort of pathogen. Components of the innate immune response include physical barriers like the skin and mucous membranes, immune cells such as neutrophils, macrophages, and monocytes, and soluble factors including cytokines and complement. On the other hand, the adaptive branch is the body's immune response which is catered against specific antigens and thus, it takes longer to activate the components involv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphoma
Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlarged lymph nodes, fever, drenching sweats, unintended weight loss, itching, and constantly feeling tired. The enlarged lymph nodes are usually painless. The sweats are most common at night. Many subtypes of lymphomas are known. The two main categories of lymphomas are the non-Hodgkin lymphoma (NHL) (90% of cases) and Hodgkin lymphoma (HL) (10%). The World Health Organization (WHO) includes two other categories as types of lymphoma – multiple myeloma and immunoproliferative diseases. Lymphomas and leukemias are a part of the broader group of tumors of the hematopoietic and lymphoid tissues. Risk factors for Hodgkin lymphoma include infection with Epstein–Barr virus and a history of the disease in the family. Risk factors for common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immunity (medical)
In biology, immunity is the capability of multicellular organisms to resist harmful microorganisms. Immunity involves both specific and nonspecific components. The nonspecific components act as barriers or eliminators of a wide range of pathogens irrespective of their antigenic make-up. Other components of the immune system adapt themselves to each new disease encountered and can generate pathogen-specific immunity. Immunity is a complex biological system that can recognize and tolerate whatever belongs to the self, and to recognize and reject what is foreign (non-self). Innate and adaptive Innate Immunity First off, the immune system is a system in the body of animals that enables animals to avoid or limit many infections caused by pathogens. Pathogens are disease causing agents, causing a wide range of illnesses. As for Diseases it's when structure of an organism is negatively affected other than external injury. Both diseases and pathogens affect the immune system causing ill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gross Anatomy
Gross anatomy is the study of anatomy at the visible or macroscopic level. The counterpart to gross anatomy is the field of histology, which studies microscopic anatomy. Gross anatomy of the human body or other animals seeks to understand the relationship between components of an organism in order to gain a greater appreciation of the roles of those components and their relationships in maintaining the functions of life. The study of gross anatomy can be performed on deceased organisms using dissection or on living organisms using medical imaging. Education in the gross anatomy of humans is included training for most health professionals. Techniques of study Gross anatomy is studied using both invasive and noninvasive methods with the goal of obtaining information about the macroscopic structure and organization of organs and organ systems. Among the most common methods of study is dissection, in which the corpse of an animal or a human cadaver is surgically opened and its o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gray's Anatomy
''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter, and first published in London in 1858. It has gone through multiple revised editions and the current edition, the 42nd (October 2020), remains a standard reference, often considered "the doctors' bible". Earlier editions were called ''Anatomy: Descriptive and Surgical'', ''Anatomy of the Human Body'' and ''Gray's Anatomy: Descriptive and Applied'', but the book's name is commonly shortened to, and later editions are titled, ''Gray's Anatomy''. The book is widely regarded as an extremely influential work on the subject. Publication history Origins The English anatomist Henry Gray was born in 1827. He studied the development of the endocrine glands and spleen and in 1853 was appointed Lecturer on Anatomy at St George's Hospital Medical School in London. In 1855, he approached his colleague Henry Vandyke Carter with his idea to produce an inexpensive and ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waldeyer's Tonsillar Ring
Waldeyer's tonsillar ring (pharyngeal lymphoid ring, Waldeyer's lymphatic ring, or tonsillar ring) is a ringed arrangement of lymphoid organs in the pharynx. Waldeyer's ring surrounds the naso- and oropharynx, with some of its tonsillar tissue located above and some below the soft palate (and to the back of the mouth cavity). Structure The ring consists of the (from top to bottom): * 1 pharyngeal tonsil (or "adenoid"), located on the roof of the nasopharynx, under the sphenoid bone. * 2 tubal tonsils on each side, where each auditory tube opens into the nasopharynx * 2 palatine tonsils (commonly called "the tonsils") located in the oropharynx *lingual tonsils, a collection of lymphatic tissue located on the back part of the tongue Terminology Some authors speak of two pharyngeal tonsils/two adenoids. These authors simply look at the left and right halves of the pharyngeal tonsil as two tonsils. Many authors also speak of lingual tonsils (in the plural), because this accumulation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal-associated Lymphoid Tissue
Nasal- or nasopharynx- associated lymphoid tissue (NALT) represents immune system of nasal mucosa and is a part of mucosa-associated lymphoid tissue (MALT) in mammals. It protects body from airborne viruses and other infectious agents. In humans, NALT is considered analogous to Waldeyer's ring. Structure NALT in mice is localized on cartilaginous soft palate of upper jaw, it is situated bilaterally on the posterior side of the palate. It consists mainly of lymphocytes, T cell and B cell enriched zones, follicle-associated epithelium (FAE) with epithelial M cells and some erythrocytes. M cells are typical for antigen intake from mucosa. In some areas of NALT, there are lymphatic vessels and HEVs (high endothelial venule). Dendritic cells and macrophages are also present. NALT contains about same amount of T cells and B cells. The T-cell population contains about 3–4 times more CD4+ T cells than CD8+ T cells. Most of T cells are with αβ T cell receptor (TCR) and only f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peyer's Patches
Peyer's patches (or aggregated lymphoid nodules) are organized lymphoid follicles, named after the 17th-century Swiss anatomist Johann Conrad Peyer. * Reprinted as: * Peyer referred to Peyer's patches as ''plexus'' or ''agmina glandularum'' (clusters of glands). From (Peyer, 1681), p. 7: ''"Tenui a perfectiorum animalium Intestina accuratius perlustranti, crebra hinc inde, variis intervallis, corpusculorum glandulosorum Agmina sive Plexus se produnt, diversae Magnitudinis atque Figurae."'' (I knew from careful study of more advanced animals, the intestines bear — often here and there, at various intervals — clusters of glandular small bodies or "plexuses" of diverse size and shape.) From p. 15: ''"(has Plexus seu agmina Glandularum voco)"'' (I call them "plexuses" or clusters of glands) He described their appearance. From p. 8: ''"Horum vero Plexuum facies modo in orbem concinnata; modo in Ovi aut Olivae oblongam, aliamve angulosam ac magis anomalam disposita figuram cerni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut-associated Lymphoid Tissue
Gut-associated lymphoid tissue (GALT) is a component of the mucosa-associated lymphoid tissue (MALT) which works in the immune system to protect the body from invasion in the gut. Owing to its physiological function in food absorption, the mucosal surface is thin and acts as a permeable barrier to the interior of the body. Equally, its fragility and permeability creates vulnerability to infection and, in fact, the vast majority of the infectious agents invading the human body use this route. The functional importance of GALT in body's defense relies on its large population of plasma cells, which are antibody producers, whose number exceeds the number of plasma cells in spleen, lymph nodes and bone marrow combined. GALT makes up about 70% of the immune system by weight; compromised GALT may significantly affect the strength of the immune system as a whole. Structure The gut-associated lymphoid tissue lies throughout the intestine, covering an area of approximately 260–300 m2. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
