Archive for the ‘Endocrinology’ Category

Thyroid Cancer: Papillary Carcinoma

Thursday, May 13th, 2010

Papillary carcinoma is the most common among malignant tumors of the thyroid (60-70% of all thyroid carcinomas). Women are affected two to three times more often than men. It is more common in young people, but in the elderly has increased malignancy.

Papillary Carcinoma

Papillary Carcinoma

It is more common in patients with a history of exposure to radiation and spreads through the lymphatic. You may find lateral aberrant thyroid remnants that are actually occult metastases with a benign histological appearance. These well-differentiated carcinomas may be TSH-dependent and may develop in the context of goiters secondary to Hashimoto’s thyroiditis. Many papillary carcinomas contain follicular elements, but this does not change the basic biology of the tumor. (more…)

Goiters and nodules

Thursday, March 18th, 2010

1 – goiters:
Definition:
Diffuse increase in the volume of the thyroid gland that is not cancer or thyroiditis, which is not accompanied by disturbance of thyroid function.
Mechanisms:

  • Inability of the thyroid gland to provide the amount of hormone needed to require the agency at some point.
  • The decrease in hormone levels will lead to hyper-secretion of TSH, which will cause an enlargement of the gland.

Causes:

  • Iodine deficiency
  • Partial deficiency in thyroid hormones
  • Using drugs that block the conversion of iodine (eg lithium) or certain foods (cabbage, rape)

Epidemiology:

  • More common in women
  • Depending on their frequency in a given population, it is called endemic goiter and sporadic.
  • Endemic goiters occur in certain regions of the world generally have a deficiency in iodine (eg mountainous regions)

(more…)

Ovaries

Thursday, December 10th, 2009

Ovarian endocrine function is devolved to the follicle cells surrounding the oocyte during its development and from which will form the corpus luteum.
As the gamete formation, the endocrine function of the ovary is cyclical secretion of ovarian hormones occurs at a pace that is superimposed on the reproductive cycle.
Ovarian castration has different effects depending on the age at which it is used:

  • before puberty, it causes the persistence of infant genital tract, absence of puberty, obesity;
  • After puberty, it causes regression of the genital tract, mitigation of secondary sexual characteristics, the suppression of reproductive function cycle arrest genital obesity.
  • The administration of ovarian hormones corrects the effects of castration. At excessive doses, they cause the child early development of the genital tract and its annexes.

The ovary secretes four groups of hormones estrogen, progesterone, a small amount of androgens and the group of inhibin and cybernines. Unlike other hormones, inhibin and cybernines are not steroid. (more…)

The Adrenal

Wednesday, December 9th, 2009

The adrenal glands are two in number, one right and one left, they are each located near the upper pole of the kidney match. Their average size is 3 inches high, 2 cm wide, 1 cm in thickness, weighs 4 to 6 g, consistency soft buff yellow coloring.
When cut, the adrenals show will consist of two entirely different areas, that difference is reflected in their function. These two areas are:
- the cortex or adrenal cortex, located at the periphery of the gland, the color yellow. It is formed by three layers of glandular cells, these three layers of cells bearing the names of areas glomerular, fascicular and reticular;
- medulla or the adrenal medulla, looking brown-red occupies the center of the gland. It is composed of polygonal cells in cords, stuffed enclaves stain; these enclaves can be highlighted by a special chemical reaction, the chromaffin reaction.
Numerous experiments ablation of adrenal glands in animals performed since Brown-Sequard in 1856 showed that the adrenal cortex is essential to life while the medulla is not.
The removal of the adrenal cortex in animals, as do humans, causes death in 1 to 5 days in a table involving digestive disorders, a cardiovascular collapse and prostration leading to coma. The biological tests show serious disturbances on the equilibrium and metabolism of water and on the balance of electrolytes (sodium and potassium in particular).
The administration of adrenal extracts in adrenalectomized animals corrects these problems.

Adrenocortical hormones
The cortex secretes many hormones whose chemical composition is now well defined and their manufacture in the adrenal (biosynthesis) and their metabolism in the body. The physiological action of some compounds is however still unknown. (more…)

The Hypothalamus

Wednesday, December 9th, 2009

This is the real brain neuro-endocrine organization, overseeing the endocrine function of the pituitary gland, and from there to most major endocrine functions of the body.
Within the hypothalamus were individually a number of nuclei (supraoptic, paraventricular nucleus, nucleus infundibular, nuclei accessories, etc.), place of preparation of hypothalamic hormones.
The connections between hypothalamus and pituitary differ depending on whether the pituitary gland or posterior pituitary:
I.es connections with the anterior pituitary are mixed neurovascular the products of secretion in the hypothalamus are routed first along the axons are directed to the pituitary via infindibulum then dumped in the vascular pituitary which leads up cells anterior pituitary;
The connections with the posterior pituitary are nervous pure: the hypothalamic hormones are fed to the posterior lobe of the pituitary where they are stored. (more…)

The Pituitary

Tuesday, December 8th, 2009

The pituitary is a small gland hung to the floor of the third ventricle by a narrow stalk, the pituitary stalk, and housed in the sella dug the body of the sphenoid. Its weight is 0.60 g, the size of a pea.
It consists of three parts, whose functions are totally different: the anterior lobe, intermediate lobe and the posterior lobe.

The Pituitary

The Anterior Lobe
The anterior pituitary or adenohypophysis is composed of two kinds of cells: cells chromophil rich granules or acidophilic (40% of anterior pituitary cells) or basophils (10% of cells) and cells chromophobe (50% cells) devoid of granules.
The anterior pituitary secretes many susbtances, hormones or stimulines true:

Growth hormone GH (Grow Hormone)
It is also known as growth hormone. It ensures a harmonious development of the human body and is responsible for the size of the subject. It stimulates growth and therefore in this specific action on the growth plates that hypertrophy significantly under its action. The hypophysectomy leads to arrest of growth in young animals, administration of excessive growth hormone to a normal growth track leads to gigantism. (more…)

Thyroid

Monday, December 7th, 2009

It is the largest of the endocrine glands. It is located on the anterior neck, below the cartilages of the larynx, trachea cons it covers the first ring.
It consists of two lateral lobes united to each other by a narrow portion, the isthmus. Its overall shape reminds that of H. Its texture is firm, his grayish pink, its average weight 20 to 25 g.

Thyroid

Histologically, the thyroid gland appears as formed by the juxtaposition of many cell blocks which we give the name of thyroid vesicles. Each vesicle is formed and thyroid:
* the center is occupied by a body more or less voluminous gummy substance, yellowish, devoid of any cell. This substance is called colloid;
* each cluster of colloid is surrounded by a single layer of polyhedral epithelial cells. These are cells that develop the colloid to have in reserve in the center of vesicles;
* between thyroid vesicles are very rich capillary network. The appearance of thyroid cells and the amount of colloid contained in the vesicles vary depending on the degree of activity of the gland. (more…)

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