Endocrine system

Structure of Endocrine System

The endocrine system consists of cells, tissues, and organs that produce hormones or other chemical substances. The organs of endocrine system act together to control body activities and maintain homeostasis. In most people, the pancreas, the adrenal, pituitary, thyroid, and parathyroid glands, and ovaries or testicles work in tandem. The endocrine system regulates various functions of a human organism. It functions as a control system for the human body. Unlike other organs and body parts that enable to move, breathe, eat,

or sense the world around us, the endocrine system influences the body's processes. Along with nervous system, it coordinates the body's activities and responses to usual and unusual events.

Although both the endocrine system and the nervous system regulate the activities of structures in the body, they do so in different ways. These two systems cannot be separated completely either anatomically or functionally. For example, some hormones secreted by endocrine glands affect the nervous system and markedly influence its activity.

The key mechanism of the endocrine system is the hormone. Different types of endocrine hormones are secreted by different glands (pituitary gland, thyroid gland, parathyroid glands, pancreas, adrenal glands, gonads: ovaries and testicles, pineal gland, and thymus gland). Most of these hormones are released into the bloodstream so that they can deliver instructions to various organs and tissues. The pancreas, for example, secretes the insulin hormone, which enables the body to regulate the amount of sugar in the bloodstream. In response to stress or other stimuli, the adrenal glands secrete adrenaline, which produces a sudden and remarkable burst of energy.

Similarly, the pituitary, thyroid, parathyroid, and gonadal glands influence certain body functions. Glands, which send the chemical substances into ducts leading to external body surfaces, are called exocrine glands. They are mammary, salivary, lacrimal and sweat glands.

A hormone is an organic substance with a special molecular structure secreted by definite cells that has an effect on the function of another cells. Although hormones circulate throughout the body via the bloodstream, each hormone influences on only certain organs (target organs) or tissues. So, several types of chemicals are produced by cells and act as chemical messengers, but not all of them are hormones.

Hormones are proteins, glycoproteins, polypeptides, derivatives of amino acids, or lipids (steroids or derivatives of fatty acids).

As a rule, the greater the amount of a particular hormone in the bloodstream, the greater activity of the target organ. Some hormones (such as several of those produced by the pituitary gland) control other glandular activity, but virtually every system in the body is subject to the influence of the hormones, either directly or indirectly.

Ex. 15. Translate the following words and word-combinations into English:

Адреналін, епінефрин; залозовий, такий, що стосується залози; гіпофіз; щитоподібна залоза; прищитоподібна | залоза; підшлункова залоза; надниркова залоза; здійснювати вплив, впливати; подразники, стимули|стимул-реакції|; шишкоподібна | залоза; загруднинна залоза, тимус|; гормони, що виробляються ендокринними залозами; жирні кислоти.

Ex. 16. Translate the text “Endocrine System” into Ukrainian.

Ex. 17. Answer the following questions:

1. What does the endocrine system consist of? 2. What is the function of endocrine system? 3. What glands of external secretion do you know? 4. What glands are the glands of internal secretion? 5. What is a hormone? 6. Where do the hormones circulate?

Ex. 18. Read the following abstract and say what it deals with:

Pituitary gland is at the base of the brain. Thyroid gland is located on either side of the trachea below the thyroid cartilage. Parathyroid glands are located on the dorsal side of the thyroid gland. Pancreas is behind the stomach. The adrenal glands are situated one on top of each kidney.

Ex. 19. Choose the correct terms (parathyroid gland; thyroid gland; adrenal glands; endocrine gland; pancreas; exocrine gland; pituitary gland) for the following definitions:

1. Gland that releases its secretion internally into a body fluid. 2. A gland that releases its secretion to the outside through a duct. 3. A set of glands located near the surface of the thyroid gland. 4. This is a largest gland of the human body. 5. This gland is located in the neck and consists of two lobes. Its hormones are thyroxine and calcitonin. 6. These glands are located atop the kidneys. Each gland consists of a medulla and a cortex. 7. This gland is attached to the base of the brain, has an anterior lobe and a posterior lobe. Most its secretion are controlled by the hypothalamus. Its hormones are growth hormone, thyroid-stimulating hormones, and some others.

Ex. 20. Choose the correct answer:

A mother consulted the doctor about her son who had grown up in height about 18 cm during the summer. On examination: height – 190 cm, weight – 68 kg. What endocrine gland’s hypersecretion may cause this condition? (thyroid gland, epiphysis, adrenal gland, pituitary gland, pancreas)

Ex. 21. Write out key words of the text “Endocrine System”.

Ex. 22. Make up a plan of the text “Endocrine System”.

Ex. 23. Give a summary of the text “Endocrine System”.

Ex. 24. Pronounce and memorize the words to the theme studied:

Secretory [sI'krI:tqrI] activity секреторна діяльність; extension подовження; band смуга, зона; зв'язка; vascular судинний; triiodothyronine ["traIaI'OdqTaI'ronIn] трийодтиронін; tetraiodothyronine тетрайодтиронін; thyroxine [TaI'rOksIn] тироксин (гормон щитоподібної залози); parietal [pq'raIItl] парієтальний, пристінковий; peritoneum ["perItqu'nI:qm] очеревина; adrenal cortex ['kO:teks] кора надниркової залози; adrenal medulla [me'dAlq] мозкова речовина надниркової залози; pancreatic islet (Langerhans islet) ['la:Ngqha:ns 'aIlIt] острівець Лангерганса, панкреатичний острівець; norepinephrine ['nourepI'nefrIn] норепінефрин, норадреналін; circulatory system система кровообігу, кровотворна система; glucagon ['glu:kqgOn] гіперглікемічний гормон підшлункової залози, глюкагон; immature ["Imq'tjuq] cell незріла клітина.

Ex. 25. Read the following words and word-combinations:

Hypophysis; antidiuretic; hypothalamus; molecule; initiate protein synthesis; embryonic; capsule; mesoderm; elongate; enzyme.

Ex. 26. Read the following text: