One of the important group of structures known as the endocrine glands, the thyroid consists of two lobes connected together by a narrow portion called the isthmus. Each lobe is about 2 inches long and lies by the side of the larynx (q.v.) and the upper part of the trachea; the isthmus usually covers the second, third and fourth rings of the trachea. The gland is attached to the cricoid cartilage of the larynx and moves upwards with the larynx in the act of swallowing. The blood supply of the organ is unusually liberal for its size.
The minute structure of the thyroid is seen to consist of a multitude of small spaces, or alveoli, lined with cubical cells and filled with colloid substances. In infancy and at other times when the gland is exceptionally active, the contents of the alveoli are watery. From this thyroid secretion a crystalline substance known as thyroxin, and containing about 60 per cent of iodine, has been extracted.
The thyroid secretion is absorbed by the lymphatic’s and blood vessels. Its great importance in controlling the metabolism and growth of the body is demonstrated by the fact that a congenital deficiency in the thyroid causes cretinism, while a deficiency occurring in adult life leads to myxedema. A cretin is a dwarf and an idiot, and the subject of myxedema becomes heavy and coarse in appearance and dull and stupid in mind. Fortunately any such deficiency in the thyroid gland can be made good by feeding the patient on the extract of the thyroid gland of animals.
The extract is even effectual in reducing the weight in ordinary obesity, but as it is a very powerful agent has to be handled very carefully. Over dosage causes restlessness, headache, insomnia, a very rapid pulse and other symptoms, the ensemble of symptoms being referred to as thyroidism. An excessive activity of the gland occurs in the disorder known as exophthalmic goiter, which is characterized by nervousness, tremor, rapidity of the pulse wasting of the body, and in typical instances by protrusion of the eyeballs.
A diminishing functioning of the thyroid gland is called hypothyroidism, an excessive functioning, hyperthyroidism, and it is necessary to remember that instances of either of insufficient degree to constitute such latent manifestations as myxedema or exophthalmic goiter may occur, and sometimes in the slighter degrees the significance of the symptoms may be overlooked. Any enlargement of the thyroid gland is commonly referred to as a goiter. See: Goiter..
Application and treatment:
Bone is developed from hyaline cartilage. Fibers first form in the matrix and round these lime salts are deposited. In the dentine, of which teeth are formed, and which resembles bone, mineral salts have also been laid down.
A type of connective tissue, known as areolar tissue, which occurs in the subcutaneous tissue, in the sheaths of organs, nerves and blood vessels and elsewhere, consists of cells, ground substance and fibers, both white and yellow.
Adipose or fatty tissue consists of areolar tissue fibers, both white and yellow. Adipose or fatty tissue consists of areolar tissue in which cells have become swollen with fat.
A tissue composed of a network made up of white fibers and an odd yellow one, and a rather fluid matrix, is called retiform tissue. When the spaces are filled with lymph corpuscles it is called lymphoid tissue. This occurs in the tonsil and elsewhere.
In the developing embryo there are three primitive layers, an outer one, known as the epiblast, or ectoderm; an inner, known as the hypoblast, or entoderm; and a middle one, called the mesoblast, or mesoderm. From the first are developed the surface epithelium and the nervous tissues; from the second most of the epithelial lining of the alimentary and respiratory tracts; and from the third the muscular and connective tissues. See: Blood.. Bone..
Application and treatment:
In general lack of conductivity is caused by lack of electrolyte in the body and the same considerations as given in Impotence. Drink 1/2 teaspoon of whey (organic sodium) and 1/2 teaspoon of rice polishings (potassium in organic form) in 1/2 glass of polarized positive water daily. After using electronic pads, take 1/2 glass of polarized positive water with 1/2 teaspoon of acidophilus to recover “good” bacteria.