Thymus Health Dictionary

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Thymus: From 2 Different Sources

A gland that forms part of the immune system.

The thymus lies behind the sternum and consists of 2 lobes that join in front of the trachea.

Each lobe is made of lymphoid tissue consisting of lymphocytes, epithelium, and fat.

The thymus conditions lymphocytes to become T-cells.

It plays a part in the immune response until puberty, gradually enlarging during this time.

After puberty, it shrinks, but some glandular tissue remains until middle-age.

Health Source: BMA Medical Dictionary
Author: The British Medical Association
n. a bilobed organ in the root of the neck, above and in front of the heart. The thymus is enclosed in a capsule and divided internally by cross walls into many lobules, each full of T lymphocytes (white blood cells associated with antibody production). In relation to body size the thymus is largest at birth. It doubles in size by puberty, after which it gradually shrinks, its functional tissue being replaced by fatty tissue. In infancy the thymus controls the development of *lymphoid tissue and the immune response to microbes and foreign proteins (accounting for allergic response, autoimmunity, and the rejection of organ transplants). T lymphocytes migrate from the bone marrow to the thymus, where they mature and differentiate until activated by antigen. —thymic adj.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Thymus Gland

The thymus gland was given its name by Galen in the second century AD because of its resemblance to a bunch of thyme ?owers. It has two lobes and lies in the upper part of the chest. The centre (cortex) resembles LYMPHOID TISSUE and is made up of masses of small round cells called thymocytes (see THYMOCYTE; LYMPHOCYTE). The medulla is more loosely cellular and consists of a stroma which contains far fewer lymphocytes than are in the cortex.

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

Thymus Serpyllum

Linn.

Family: Labiatae; Lamiaceae.

Habitat: Native to North America; also found in temperate Himalayas from Kashmir to Nepal; grown in gardens in western India.

English: Mother-of-thyme, Wild Thyme. Thymus vulgaris (Garden Thyme) is found in the Nilgiris at higher elevations.

Ayurvedic: Ajagandhaa, Vana- Yavaani. (Not to be confused with Yavaani, Ajmodaa, Shataahvaa, Raajikaa and Tilaparni.)

Unani: Haashaa, Jangali Pudinaa. Thysanolaena agrostis Nees.

Action: Antiseptic, antibacterial, antifungal, antiviral, antispasmodic, mild sedative, expectorant. T. serpyllum and T. vulgaris L. are used for coughs and common cold.

Key application: German Commission E approved T. vulgaris for symptoms of bronchitis, whooping cough and catarrhs of the upper respiratory tracts. Also to treat stomatitis. (ESCOP.)

The British Herbal Pharmacopoeia recognizes expectorant activity of T. serpyllum.

T. serpyllum contains more linalool and p-cymol than Garden Thyme (T. vulgaris). Major constituent of the volatile oil of both the species (highly variable) is thymol; with carvacrol (lesser amount in T. serpyllum, higher in T. vulgaris), 1,8-cineole, borneol, geraniol, linalool. bornyl and lina- lyl acetate, thymol methyl ether and alpha-pinene.

Flavonoids include apigenin, lute- olin, thymonin, naringenin; other constituents include labiatic acid, caffeic acid, tannins.

The flavonoid fraction has shown to have a potent effect on smooth muscle on guinea-pig trachea and ileum.

Thymol is expectorant and antiseptic. Thymol and carvacrol are spasmolytic. Thymol is also urinary tract antiseptic and anthelmintic.

Dosage: Whole plant—3–5 g powder. (CCRAS.)... thymus serpyllum

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