Diencephalon - is a relatively small brain structure (diagram 149), which has a very complex structure and is involved in the implementation of many

Diencephalon structure and functions (thalamus, hypothalamus, epithalamus)

Diencephalon — is a relatively small brain structure (diagram 149), which has a very complex structure and is involved in the implementation of many important functions. The main structural formations of diencephalon are the thalamus (visual hillocks), hypothalamus (hypothalamus) and epithalamus. The central part of the diencephalon consist the third ventricle of the brain.

The thalamus forms the lateral ventricular walls. It is almost entirely formed of gray matter. The thalamus has almost 40 cores. By function, they are divided into switching, associative and non-specific. The switching cores — are the body's neurons, which transmit the excitement of receptors to the appropriate section of the sensitive cortex.

In the associative thalamic nuclei occurs initial analysis and synthesis of information. They get the excitement from different switching cores, select the strongest and the most important, and send them to the associative areas of the cerebral cortex. Non-specific kernel receive regular information from all the receptors and send excitement to all departments of the cerebral cortex, maintaining its active state. These nuclei belong to the reticular formation of the intermediate brain.

Diagram 149. The structure of the cerebellum and diencephalon: 1 — thalamus; 2 — the brain stem; 3 — the midbrain; 4 — bridge; 5 — the medulla oblongata; 6 — the spinal cord; 7 — the cerebellum; 8 — bark of the cerebellum; 9 — the nucleus of the cerebellum

Hypothalamus forms the bottom of the third ventricle. Structurally and functionally it’s closely related to the pituitary gland (a gland of internal secretion). There are several tens of cores in the hypothalamus. This is the supreme center of the autonomic regulation of the body, which ensures the maintenance of homeostasis. It has been established that part of the hypothalamus’ nuclei are the regulatory center of the sympathetic nervous system, and the rest — the parasympathetic. Hypothalamus receives information from internal organs receptors, as well as from its own receptors placed on the bottom of the third ventricle. These are temperature, chemical and osmotic receptors. By analyzing this information, the structure of the hypothalamus determine the nature and extent of homeostasis violations. Via the autonomic nervous system and the endocrine glands the regulatory effect on the activity of internal organs is performed, aimed at the resumption of homeostasis performance. Taken from http://worldofschool.org

There are hunger and satiety centers, thermal centers, centers of sleep, wakefulness, and other ones in the hypothalamus. In addition, the hypothalamus located centers of pleasure and punishment that guide human behavior to meet the physiological needs (motivational centers). Rats that had implanted electrodes in the center of pleasure constantly shocked themselves with electric shock, refusing food and water. Such incongruous (inappropriate) behavior of animals usually leads to their death. It is believed that a violation of the centers related to the emergence of drug and alcohol dependency. Damage of the hypothalamus structures (as a result of trauma, hemorrhage, tumor occurrence, infection and so forth) leads to significant violations of the metabolic processes and energy. For example, a tumor that is constantly annoying hunger center causes the need for constant food consuming (hyperphagia) and as a result — a strong obesity develops. On the contrary, a permanent irritation of the satiety center leads to the development of dystrophy.

The main structure of epithalamus is an endocrine gland (pineal gland).

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