Lymphatic system

Lymphocytes are a type of white blood cell that are an important part of the immune system. They are divided into two main types: B-cells and T-cells. B-cells are responsible for producing antibodies that help fight off bacteria and viruses, while T-cells help to identify and destroy infected cells. Both types of lymphocytes are essential for a healthy immune system and work together to protect the body from disease.

Memory cells are a type of immune cell that are able to quickly respond post any subsequent encounter with the same antigen. Memory cells are generated after an initial encounter with an antigen, and are able to recognize and respond to the same antigen more quickly and effectively than the initial response. Memory cells are a key component of the adaptive immune system, and are responsible for providing long-term immunity to a pathogen.

Basophils, eosinophils and Neutrophils are types of white blood cells known as granulocytes. Granulocytes are so named because of the granules that are visible when viewed through a microscope. These granules contain enzymes that help the cells to fight off infection. Granulocytes are the most abundant type of white blood cell and are the body's first line of defense against infection.

Cytotoxic T cells are a type of white blood cell that are part of the immune system. They are responsible for recognizing and destroying cells that are infected with viruses or other pathogens. They do this by inserting perforins into the target cell's membrane, which creates pores that allow toxic molecules to enter the cell and cause it to die.

Opsonization is not a cardinal sign of inflammation. Cardinal signs of inflammation are redness, heat, swelling and pain. Opsonization is a process in which antibodies or complement proteins attach to the surface of a microorganism, making it more susceptible to phagocytosis by phagocytes.

Free radicals are molecules that contain one or more unpaired electrons, making them highly reactive and unstable. They are released in the respiratory burst, which is a process that occurs when neutrophils, a type of white blood cell, are activated to fight off an infection. Free radicals have the potent of cell-killing ability, which is why they are so important in the body's defense against infection.

Costimulation is the process by which a helper T cell is activated when it binds to a class II MHC protein on a displaying cell. This process is necessary for the T cell to become activated and to initiate an immune response. Costimulation is a key step in the activation of the immune system, as it helps to ensure that the immune system only responds to foreign antigens and not to self-antigens.

T lymphocytes, also known as T cells, are a type of white blood cell that play a central role in the body's immune system. They are produced in the bone marrow and mature in the thymus, where they develop immunocompetence. T cells are responsible for recognizing foreign antigens, activating other immune cells, and producing cytokines to regulate the immune response. NK cells, or natural killer cells, are another type of white blood cell that are involved in the immune response, but they do not develop immunocompetence in the thymus. B lymphocytes, or B cells, are also a type of white blood cell that are involved in the immune response, but they develop immunocompetence in the bone marrow, not the thymus.

An immune response is a reaction of the body's immune system to a foreign substance, such as a virus, bacteria, or toxin. When the body is exposed to a nonself particle, it triggers an immune response, which is the body's way of defending itself. The body recognizes the nonself particle as an antigen and produces antibodies to fight it. Antibodies are proteins that recognize and bind to antigens, helping the body to destroy them.

Red Blood Cells (RBCs) are the most common type of blood cell and are not part of the immune system. RBCs are responsible for carrying oxygen and carbon dioxide throughout the body. They are produced in the bone marrow and have a lifespan of about 120 days. Unlike other blood cells, RBCs do not contain a nucleus and are unable to divide. They are also unable to recognize and respond to foreign substances, making them unable to fight off infections.

Memory B-cells of the immune system have a life span of a few years to the whole life. These cells do not produce antibodies but when the same pathogen attacks for the second time, they differentiate into effector cells.

Small Pox vaccination is a first-generation vaccine where an attenuated form of the virus is injected into the body of the patient. The first vaccination was developed by Edward Jenner against smallpox.

Primary immune response is the first immune response developed during the first encounter with the antigen. It is feeble but relatively longer. The secondary immune response is a quick heightened immune response against a subsequent encounter with the same antigen. It is due to the presence of memory cells against that antigen. Hence, the secondary response is more intense than the primary response.

Clonal selection is the process of formation of a large number of effector cells against a particular antigen. It involves the formation of a clone of cells by each activated T-lymphocyte and antibody-producing plasma cells by activated B-lymphocyte, each exhibiting the specificity for the same antigen.

IgA immunoglobulins are also called secretory immunoglobulin because it is present in all the body secretions including colostrum and mother’s milk. It functions as the first line of defence against ingested and inhaled pathogens by activating alternative pathways of the complement system.

Cyclosporin is an immunosuppressant drug. This drug prevents rejection of kidney, heart and liver transplants. It destroys T-cell mediated immune responses while spares humoral antibody responses.

For organ or tissue transplantation, the preference order for the donor is Identical twin > Sibling > Parent > Unrelated Donor. As there are antigens which are likely to be attacked by recipient T-cells and antibodies, the recipients of organ or tissue transplants are always given immunosuppressants to reduce the risk of rejection.

Immunosuppressants are chemicals which suppress the immune reaction of the body so that the antigens of the patient’s body do not attack the transplanted organs or tissues.

SCID stands for Severe Combined Immunodeficiency where very few T-lymphocytes are formed and B-lymphocytes are also deficient. As a result, the patient dies of even minor infections.

Immunodeficiency diseases are disorders of the immune system where one or more components of innate or acquired immunity become defective due to gene mutations, Infections, Malnutrition or even accidents.

Lymphoid organs are not responsible for the destruction of lymphocytes. Lymphoid organs are those organs having lymphatic tissues where maturation, proliferation and differentiation of lymphocytes occur.

MALT is not found in the liver. MALT is a lymphoid tissue which is located within the mucosal lining of the major tracts like respiratory, digestive and urogenital tracts.

MALT stands for Mucosal Associated Lymphoid Tissue. It constitutes about 50% of the lymphoid tissue in the human body.

The spleen is a large bean-shaped organ located in the upper left side of the abdomen. It is also known as the "Graveyard of RBCs" due to its role in filtering out old and damaged red blood cells from the bloodstream. The spleen contains lymphocytes, phagocytes, and a large number of erythrocytes, which help to trap and destroy blood-borne microorganisms.

The Thymus is an organ located near the heart and beneath the breast bone. It is also known as the Throne of Immunity or training school of T-lymphocytes, as it is the site where T-lymphocytes mature.

Hematopoitic stem cell (HSC) is a multipotent cell, meaning it can give rise to a number of cells by following two pathways. One pathway gives lymphoid progenitor cell while the other gives myeloid progenitor cell.

Monocyte is a myeloid progenitor cell and is a part of white blood cells. B-cells, T-cells, and NK cells are lymphoid progenitor cells.

B-cells originate from bone marrow and mature in the bursa of fabricius in birds. In mammals, the origin and maturation of B-cells take place in the bone marrow itself.

NK cells are natural killer cells, which use perforin and granzyme to kill the target cell. They can destroy malignant and virus infected cells even without the prior exposure to antigen, hence they can kill their target even without specific antigen.

Chediak-Higashi syndrome is an autosomal recessive disorder which is caused by the deficiency of NK cells. It is characterized by partial albinism, recurrent infections, and a bleeding tendency. NK cells are a type of white blood cell that helps the body fight off infections.

Polymorphonuclear leukocytes are those that have an irregular-shaped nucleus with more than two lobes. Their cytoplasmic matrix is rich in substances which can kill microorganisms and increase inflammation. Macrophages, on the other hand, have a single, round nucleus and are responsible for engulfing and destroying foreign particles.

Basophils are non-phagocytic cells, which releases substances that cause an allergic response. These substances are histamine, prostaglandins, serotonins etc. Basophils have a high affinity for IgE.

Macrophages are a type of white blood cell that are derived from monocytes in the blood. They are phagocytic in nature and can take on a variety of forms, such as Kupffer cells in the liver, mesangial cells in the kidney, and alveolar macrophages in the lung. Microglial cells are the macrophages associated with the central nervous system.

Dendritic cells are derived from both myeloid and lymphoid lineages and are known to express high levels of Class II MHC molecules, making them effective antigen presenting cells.

Follicular dendritic cells do not function as antigen presenting cells as they do not originate from the bone marrow and do not express MHC II molecules on their surface.

Immunology is the branch of biology that studies the immune system, which is the body's natural defense against disease-causing agents such as bacteria, viruses, and parasites. It is a complex system that involves many different types of cells, organs, and molecules that work together to protect the body from infection and disease. Immunology also studies how the immune system develops and changes over time, as well as how it can be manipulated to treat and prevent diseases.

Acquired immunity is the type of immunity that is obtained during a lifetime. It is the immunity that is developed by the body in response to the presence of a foreign substance, such as a virus or bacteria. This type of immunity is developed through exposure to a particular antigen, which stimulates the body to produce antibodies that can recognize and fight the antigen. Acquired immunity can also be acquired through vaccination, which introduces a weakened or killed form of the antigen into the body, allowing the body to develop immunity without the risk of infection.

Antibodies are proteins produced by the immune system in response to foreign substances such as bacteria, viruses, and toxins. There are five main types of antibodies: IgA, IgD, IgE, IgG, and IgM. IgA is found in the mucous membranes of the respiratory and gastrointestinal tracts, and it is the most abundant antibody in the body. IgD is found on the surface of B cells and helps to activate them. IgE is found in the lungs, skin, and mucous membranes and is involved in allergic reactions. IgG is the most common antibody and is found in all body fluids. IgM is the largest antibody and is the first to respond to a new infection.

Cell-mediated immunity is a type of immunity that is mediated by cells. It is a type of adaptive immunity, which is specific to a particular pathogen. T cells are the main cells involved in cell-mediated immunity. They are responsible for recognizing and responding to antigens presented by antigen-presenting cells. T cells can also produce cytokines, which are molecules that help to regulate the immune response.

The immune system is the body's defense against disease-causing pathogens. It is composed of a network of cells, tissues, and organs that work together to protect the body. The immune system is made up of white blood cells, antibodies, the complement system, the lymphatic system, the spleen, the thymus, and the bone marrow. These components work together to recognize and destroy any foreign substances, such as bacteria, viruses, and toxins, that enter the body.

Hepatitis is an infectious disease caused by the hepatitis virus. Recombinant vaccines are made by introducing a gene from the virus into a harmless organism, such as a bacterium or yeast. This organism then produces a harmless version of the virus, which is used to create the vaccine. The vaccine stimulates the body's immune system to recognize and fight the virus, providing immunity against the disease.

Immunoglobulin M (IgM) is the largest immunoglobulin and is the first immunoglobulin to be produced in response to an antigen. It is primarily restricted in the circulation and is not able to cross the placenta. IgM is produced by high-affinity plasma cells and is able to protect the mucosal surface.

Interferons are a type of cytokine, a protein produced and released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites, or tumor cells. They are part of the body's natural defense system, and are produced by cells in response to the presence of pathogens. Interferons help to regulate the immune system by stimulating the production of other cytokines, which in turn activate the immune system to fight off the invading pathogen.

Basophils are a type of white blood cell that are part of the immune system. Unlike macrophages, neutrophils, and eosinophils, basophils do not perform phagocytosis, which is the process of engulfing and destroying foreign particles and microorganisms. Instead, basophils are involved in the inflammatory response and the release of histamine, which helps to protect the body from infection.

Monocytes are a type of white blood cell that are part of the immune system. They are produced in the bone marrow and circulate in the bloodstream. Monocytes can differentiate into macrophages, which are large phagocytic cells that engulf and digest cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the type of proteins specific to healthy body cells. Macrophages are also involved in the activation of the immune system.