The thyroid or thyroid gland is bulkiest of the endocrine Glande S (secreting Hormone S).
Presentation
It secretes:- the T3 or Triiodothyronine in very small quantity
- the T4 or Thyroxine
- the Calcitonine intervening in the Metabolism of the Calcium
Located at the former face of the Neck, it is surface: its deformations (one speaks about Goiter when the volume of thyroid is increased) are visible under the Peau. It is frequently the seat of pathologies: Hyperthyroïdie, Hypothyroïdie, Tumor malignant or benign. One can study it thanks to the echography and the Scintigraphie.
The thyroid one is composed of two lobes right and left connected at their lower parts by the isthmus. It presents two types of reports/ratios:
- the recurring laryngés Nerf S which pass behind and finish in the Larynx.
- the four glands Parathyroid S: small glands located at the posterior face of thyroid and playing a part in the metabolism phosphocalcic. They can have variable situations.
Morphology
The two vertical pyramidal lobes are joined together by a horizontal intermediate base: the thyroid isthmus. Generally, the thyroid gland answers 2nd and 3rd trachéaux rings; but it can have a high position: 1st and 2nd trachéaux rings, or a low position: 3rd and 4th trachéaux rings. The two lobes have a higher top, as well as a great lower base. 3 faces are described to them: médiale, posterior and antéro-side. Its height is of approximately 6 cm for a length from 6 to 8 cm. One often finds between the two lobes, therefore on the level of the isthmus, the pyramidal lobe of Lalouette , often off-set towards the left: it is a remainder of the Canal thyréoglosse.The thyroid one, moulded on the trachéo-laryngé axis, is of firm consistency, color dew, and weighs 30 grams (slightly more among women) but in the event of Goiter its weight can increase up to 100-150 grams. It is surrounded by a capsule which is clean for him and which is different from the thyroid Loge.
There exist morphological variations, being explained by the Embryologie: indeed the two lobes are sometimes distant one from the other without there being isthmus, or on the contrary can be welded giving thyroid in form V. Coming from a bud of endodermal cells incipient close to the root of the language, various positions of thyroid gland can however occur during ontogenesis: a bad migration of this outline leads then to the detection of this gland (functional or not functional) in the area lingual, cervical, even endo-thoracic.
The unit morpho-functional calculus of thyroid gland is the thyroid follicule (or thyroid blister), composed of a unistratifié epithelium of follicular cells, producing the thyroid hormones, laid out around a central light containing to it colloid: the colloid is mainly made up of the precursor of the thyroid hormones, the thyroglobuline. The thyroid follicule is a genuine trap with Iode (ion iodizes), element rare on the surface of the ground, and essential to the operation of the organization; iodine thus will be collected and stored in colloid: the biosynthesis of the thyroid hormones will be able to then proceed, iodine coming to couple itself with the thyroglobuline; the iodized thyroglobuline is then reinstated in the thyroid follicule, and is secreted in the blood current.
The thyroid follicule, apart from a majority of follicular cells, contains 1 to 2% of cells known as parafolliculaires, producing calcitonine: they however never have contact with colloid.
Vascularization
The thyroid one is a richly vascularized Organe. Indeed one finds:- Two Artery S principal:
- Three Vein S principal:
Thyroid pathologies
Hypothyroïdie
Symptomatology due to a defect of production of thyroid hormones. The thyroid one does not produce enough any more of hormones and the organization in entirety functions then with the idle.The symptoms more current are:
- very important tiredness;
- lack of concentration;
- loss of memory;
- taken weight important whereas the appetite is him decreased considerably;
- constipation;
- turbid menstrual;
- bradycardia;
- muscular pains;
- falls of hair, nails breakable;
- skins dries;
- rings;
- depressive state;
- raucous voice and well of others.
; Several hypothyroïdies:
Primary Hypothyroïdie: the thyroid gland does not manufacture enough hormones. The thyroid one is of very small size.
Secondary Hypothyroïdie: the thyroid one is of normal size. The pituitary gland does not send enough signals to the thyroid one.
Tertiary Hypothyroïdie: the hypothalamus does not manufacture enough TRH. The TRH is a hormone of the hypothalamus to stimulate the antéhypophyse to produce TSH which it must stimulate the thyroid one.
; Treatments Generally containing T4 only: Levothyrox, Synthroïd, L-thyroxine in compressed or drops, etc But there exist also treatments containing T3: Cynomel which is only of the T3, Euthyral which is an association of T4 (100 µg) and T3 (20 µg). When it is necessary to add T3 better is worth to have a treatment which makes it possible to have a suitable proportioning for each of the two hormones. The combined treatments are very difficult to manage. There also exists of other treatments: Thyroid Armor for example which contains all the hormones that the thyroid factory.
Hyperthyroïdie
Symptomatology due to an excess of production of thyroid hormones.the symptoms are in general:
- cardiovascular: tachycardia, cardiovascular erethism (quivering of the shock of the point of the heart);
- digestive: syndrome polyuro-polydipsic (drinks and urinates in great quantity), slimming, diarrhea;
- neuro-psychiatrist: tremor, agitation, turbid of mood (irritability active to the depression), sleep disorder, turbid of the food behavior (eats in excessive quantity);
- general: hypersudation (often moist hands, perspiration), hyperthermia thermophobie (high temperature and does not appreciate the high temperatures);
- muscular and articular: pain and muscular tiredness, osteoporosis.
The tobacco multiplies by ten the risk of supervening of the Maladie of Basedow, the most frequent form of the Hyperthyroïdie, and increases the risks of complications. The chronic stress, the emotional shocks and cafeine are also notorious enemies of the thyroid one.
Depression and thyroid
The Hypothyroïdie can sometimes be taken for a state of depression and the Hyperthyroïdie for a state of excitation. The thyroid diagnosis will make it possible to eliminate these false diagnoses.However recent work showed that a hypothyroïdie only treated with thyroxine can more still approach a depressive state. Rather than to prescribe an antidepressant, the doctor can sometimes propose a simple substitution of part of the amount of thyroxine (T4) by the trione (T3).
It was also shown that certain depressions resistant to the antidepressants, and without hypothyroïdie, could profit from a contribution of T3. But this remains to be checked and cannot be done without the careful regulation of a specialist.
Morphological anomalies of gland
Thyroid Goiter
Goiter multinodulaire
Thyroid function:- toxic;
- not E042 poison.
Single nodule
Cancer of thyroid the
See too
thyroid|thyroid- French Association of the patients of thyroid the
External bonds
- the Canadian Foundation of Thyroid the
- Forum “Food without thyroid”
- thyroid pathologies are treated, inter alia, in the medical encyclopedia Vulgaris
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