adj. circulating in the bloodstream; humoral *immunity requires circulating antibodies.
Composition The cellular components are red cells or corpuscles (ERYTHROCYTES), white cells (LEUCOCYTES and lymphocytes – see LYMPHOCYTE), and platelets.
The red cells are biconcave discs with a diameter of 7.5µm. They contain haemoglobin
– an iron-containing porphyrin compound, which takes up oxygen in the lungs and releases it to the tissue.
The white cells are of various types, named according to their appearance. They can leave the circulation to wander through the tissues. They are involved in combating infection, wound healing, and rejection of foreign bodies. Pus consists of the bodies of dead white cells.
Platelets are the smallest cellular components and play an important role in blood clotting (see COAGULATION).
Erythrocytes are produced by the bone marrow in adults and have a life span of about 120 days. White cells are produced by the bone
marrow and lymphoid tissue. Plasma consists of water, ELECTROLYTES and plasma proteins; it comprises 48–58 per cent of blood volume. Plasma proteins are produced mainly by the liver and by certain types of white cells. Blood volume and electrolyte composition are closely regulated by complex mechanisms involving the KIDNEYS, ADRENAL GLANDS and HYPOTHALAMUS.... blood
Habitat: Throughout India; grown in houses, gardens and temples.
English: Holy Basil, Sacred Basil.Ayurvedic: Tulasi, Surasaa, Surasa, Bhuutaghni, Suravalli, Sulabhaa, Manjarikaa, Bahumanjari, Deva- dundubhi, Apet-raakshasi, Shuu- laghni, Graamya, Sulabhaa.Unani: Tulasi.Siddha/Tamil: Tulasi, Nalla-Tulasi.Action: Leaf—carminative, stomachic, antispasmodic, antiasthmatic, antirheumatic, expectorant, stimulant, hepatoprotective, antiperiodic, antipyretic and diaphoretic. Seed— used in genitourinary diseases. Root—antimalarial. Plant—adap- togenic, antistress. Essential oil— antibacterial, antifungal.
The Ayurvedic Pharmacopoeia of India recommends the use of the leaf and seed in rhinitis and influenza; the seed in psychological disorders, including fear-psychosis and obsessions.Major components of the essential oil are eugenol, carvacrol, nerol and eugenolmethylether. Leaves have been reported to contain ursolic acid, api- genin, luteolin, apigenin-7-O-glucu- ronide, luteolin-7-O-glucuronide, orientin and molludistin.Ursolic acid, isolated from leaves, exhibited significant protection of mast cell membrane by preventing granulation and decreased histamine release. The ethanolic extract (50%) of fresh leaves, volatile oil from fresh leaves and fixed oil from seeds showed antiasth- matic activity and significantly protected guinea-pigs against histamine and dyspnoea. They also showed anti- inflammatory activity against carrage- enan-, serotonin-, histamine- and PGE-2-induced inflammation and inhibited hind paw oedema in rats.The ethanol extract (90%) of the leaves showed hepatoprotective effect against paracetamol-induced liver damage.The plant extract exhibited antiul- cerogenic property against experimental ulcers.Oral administration of alcoholic extract of leaves lowers blood sugar level in normal, glucose-fed hyperglycaemic and streptozotocin-induced diabetic rats. The activity of the extract was 91.55 and 70.43% of that of tolbutamide in normal and diabetic rats respectively.Administration of the juice of the plant affected a significant reduction in the size of urinary brushite crystals.A study of methanol extract and aqueous suspension of the leaves showed immunostimulation of humoral immunologic response in albino rats indicating the adaptogenic action of the plant.Dosage: Seed—1-2 g powder (API, Vol. IV); plant—50-10 ml infusion (CCRAS.).... ocimum sanctumHowever, pharmacologically inert compounds can relieve symptoms, and this is called the placebo e?ect. The reassurance that is associated with placebo administration is accompanied by measurable changes in body function which are affected through autonomic pathways and humoral mechanisms. Alterations in blood pressure and pulse frequency are especially common. Placebos have the ability to relieve a variety of symptoms in a consistent proportion of the population – in some studies in as many as 30 per cent. Some patients with symptoms such as pain or cough will respond to placebo medications, and an even higher proportion of patients with psychological symptoms such as anxiety or insomnia may bene?t. In judging the e?ectiveness of a drug, the comparison must be with a placebo rather than with no treatment at all.... placebo
In autoimmune disorders, disease is due to damage wrought by circulating ANTIBODIES or sensitised lymphocytes (see LYMPHOCYTE). If the disease is due to circulating humoral antibodies, removal of these antibodies from the body should theoretically relieve the disorder. This is the principle on which plasma exchange was used in the management of autoimmune diseases due to circulating antibodies. Such disorders include Goodpasture’s syndrome, SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) and MYASTHENIA GRAVIS. One of the problems in the use of plasma exchange in the treatment of such diseases is that the body responds to the removal of an antibody from the circulation by enhanced production of that antibody by the immune system. It is therefore necessary to suppress this homeostatic response with cytotoxic drugs such as AZATHIOPRINE. Nevertheless, remissions can be achieved in autoimmune diseases due to circulating antibodies by the process of plasma exchange.... plasma exchange
The thymus gland is a vital part of the immunological system. Stem cells (see STEM CELL) from the BONE MARROW come to the thymus where they develop into immunologically competent cells. There are two distinct populations of lymphocytes. One is dependent on the presence of the thymus (Tlymphocytes); the other is independent of the thymus (B-lymphocytes). Both are concerned with immune responses (see IMMUNITY). The T-lymphocyte is a cell which in the absence of antigenic stimulation (see ANTIGEN) circulates through the blood, lymph nodes and back into the circulation again over a period of more than ten years. It performs a policing role, awaiting recognition of foreign material which it is able to identify as such. It reacts by multiplication and transformation and these are the ingredients of the immune response. B-lymphocytes are produced in the bone marrow and are concerned with the production of the circulating humoral ANTIBODIES.
The most common clinical disorder associated with abnormality of the thymus is MYASTHENIA GRAVIS. Ten per cent of patients with myasthenia gravis will have a tumour of the thymus, whilst the remainder will have in?ammatory changes in the thymus called thymitis.... thymus gland
The term innate immunity is given to the protection that we are born with, such as the skin and the mucous membranes that line the mouth, nose, throat, intestines, and vagina. It also includes antibodies, or immunoglobulins (protective proteins), that have been passed to the child from the mother. If microorganisms penetrate these defences, they encounter “cell-devouring” white blood cells called phagocytes, and other types of white cells, such as natural cellkilling (cytotoxic) cells. Microorganisms may also meet naturally produced substances (such as interferon) or a group of blood proteins called the complement system, which act to destroy the invading microorganisms.The 2nd part of the immune system, adaptive immunity, comes into play when the body encounters organisms that overcome the innate defences. The adaptive immune system responds specifically to each type of invading organism, and retains a memory of the invader so that defences can be rallied instantly in the future.
The adaptive immune system first must recognize part of an invading organism or tumour cell as an antigen (a protein that is foreign to the body). One of 2 types of response – humoral or cellular – is then mounted against the antigen.
Humoral immunity is important in the defence against bacteria. After a complex recognition process, certain B-lymphocytes multiply and produce vast numbers of antibodies that bind to antigens. The organisms bearing the antigens are then engulfed by phagocytes. Binding of antibody and antigen may activate the complement system, which increases the efficiency of the phagocytes.
Cellular immunity is particularly important in the defence against viruses, some types of parasites that hide within cells, and, possibly, cancer cells. It involves 2 types of T-lymphocyte: helper cells, which play a role in the recognition of antigens and activate the killer cells (the 2nd type of T-lymphocyte), which destroy the cells that have been invaded.
Disorders of the immune system include immunodeficiency disorders and allergy, in which the immune system has an inappropriate response to usually innocuous antigens such as pollen.
In certain circumstances, such as after tissue transplants, immunosuppressant drugs are used to suppress the immune system and thus prevent rejection of the donor tissue as a foreign organism.... immune system
Congenital or inherited deficiencies can occur in either of the 2 prongs of the adaptive immune system: humoral or cellular. Deficiencies of the humoral system include hypogammaglobulinaemia and agammaglobulinaemia. The former may cause few or no symptoms, depending on the severity of the deficiency, but agammaglobulinaemia can be fatal if not treated with immunoglobulin. Congenital deficiencies of T-lymphocytes may lead to problems such as persistent and widespread candidiasis (thrush). A combined deficiency of both humoral and cellular components of the immune system, called severe combined immunodeficiency (SCID), is usually fatal in the 1st year of life unless treatment can be given by bone marrow transplant.
Acquired immunodeficiency may be due either to disease processes (such as infection with HIV, which leads to AIDS) or damage to the immune system as a result of its suppression by drugs. Severe malnutrition and many cancers can also cause immunodeficiency. Mild immunodeficiency arises through a natural decline in immune defences with age.... immunodeficiency disorders
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