The thalamus is ... The thalamus: definition, structure and functions

The development of psychiatry and neurology in modernconditions is impossible without a deep knowledge of the structure and functions of the brain. Without an understanding of the processes taking place in this body, one can not effectively treat illnesses and return people to a full life. Violations at any stage of embryogenesis - genetic anomalies or disorders, due to teratogenic effects of external factors - lead to the development of organic pathologies and irreparable consequences.

thalamus is

Important department

The brain is a complex structure of the body. It includes various elements. One of the most important departments is the intermediate department. It includes several links: the thalamus, the hypothalamus, epithalamus, and metethalamus. The most important are the first two.

Thalamus: Physiology

This element is represented as a median symmetrical formation. It is located between the middle brain and the bark. It consists of 2 departments. The thalamus is education that enters the limbic system. He performs various tasks. In the period of embryonic development, this element is considered to be the largest. It is fixed in the so-called anterior section, near the center of the brain. Nerve fibers leave the bark in all directions from it. The medial surface forms the lateral wall in the third ventricle.

thalamus of the brain

Kernels

The thalamus is part of a complex complex. It is formed of four parts. They include: the hypothalamus, epithalamus, pre-thalamus, as well as the dorsal thalamus. The last two are derived from the intermediate structure. Epithalamus consists of a pineal gland, a triangle and leashes. In this area are the nuclei involved in the activation of the sense of smell. The ontogenetic nature of epithalamus and peritolamus is different. In this regard, they are treated as separate entities. Generally, thalamus structure includes more than 80 cores.

Specificity

The thalamus of the brain includes a systemslats. It is formed by myelinated fibers and divides the different parts of the formation. Other areas are defined by neural groups. For example, intralaminar elements, periventricular nucleus and so on. The structure of the elements differs significantly from the basic thalamic part.

Classification

Each center has its own nuclei. This determines their importance for the human body. Classification of nuclei is carried out depending on their location. There are the following groups:

  1. Front.
  2. Mediodorsal.
  3. The middle line.
  4. Dorsolateral.
  5. Ventrolateral.
  6. Ventral posteromedial.
  7. The rear.
  8. Intralaminar.

thalamus physiology

In addition, the nuclei are subdivided depending on the direction of action of the neurons on:

  1. Spotting.
  2. Handling tactile signals.
  3. Auditory.
  4. Regulating balance.

Types of Centers

Relay, nonspecific andassociative kernels. The latter include a large number of middle and intralaminar formations. The relay cores receive signals, which are then projected into different parts of the cortex. They include the formations that transmit the primary sensations (ventral-posteromedial, ventral-postlateral, medial and lateral geniculate), as well as the cerebellum impulses involved (lateral ventral). Associative nuclei receive most of the impulses from the cortex. They project them back to regulate activity.

Nervous ways

The thalamus is education associated with the hippocampus. Interaction is carried out through a special pathway, in which the vault and mastoid bodies are present. To the bark, the thalamus is connected by thalamocortical rays. There is also a way in which information about itching, touching, and temperature is transmitted. It passes in the spinal cord. There are two divisions: ventral and lateral. On the first pass impulses on pain and temperature, on the second - on pressure and touch.

reticular formation of the thalamus

Blood supply

It is carried out from the connecting rear,lower lateral, lateral and middle choroidal, as well as paramedial thalamic-hypothalamic arterial vessels. Some people have an anatomical abnormality. It is represented in the form of the artery of Percheron. In this case, one trunk leaves the posterior cerebral vessel. It provides blood to the entire thalamus. This phenomenon is quite rare.

Functions

For what the thalamus responds? This education fulfills many tasks. In general, the thalamus is a kind of information concentrator. Through it there is a retransmission between different subcortical areas. For example, each sensitive system except the olfactory system uses thalamic nuclei that receive and transmit signals to the corresponding primary regions. For the visual site, incoming impulses from the retina are sent to the lateral departments through a center projecting information to the corresponding cortical area in the occipital sector. A special role belongs to the thalamus in the process of wakefulness and sleep regulation. The nuclei interacting with the cortex form specific chains that are associated with consciousness. Activity and excitation also regulates the thalamus. Damage to this formation usually leads to coma. The thalamus is associated with the hippocampus, performs certain tasks in the organization of memory. It is believed that its areas are connected to some mesio-temporal areas. Due to this, differentiation of familiar and recollective memory is provided. In addition, there are suggestions that the thalamus also participates in the neural processes necessary for motor regulation.

thalamus structure

Pathologies

As a result of a stroke, thalamicsyndrome. It is manifested by one-sided burning (heat), aching sensations. It is often accompanied by mood swings. Two-sided ischemia of the thalamic region can provoke serious violations. For example, they include an akinetic mutism, oculomotor disorders. When the artery of Percheron is blocked, a bilateral infarction can occur.

Reticular formation of the thalamus

In the central section of the trunk there is a clustercells. They are intertwined with a huge number of fibers going in all directions. If we consider this formation under a microscope, then it looks like a network. Therefore, it was called the reticular formation. Neural fibers retreat to the cortex and form non-specific pathways. With their help, activity is maintained in all parts of the central nervous system. Under the influence of the formation, reflexes are amplified. In this cluster there is a selection of information. In the overlying areas only new and important information arrives. The activity of the formation is always at a high level, because signals from all receptors go through it.

for which the thalamus responds

Neurons

They show high sensitivity topharmacological agents and hormones. Such drugs as "Reserpine", "Aminazine", "Serpasil" and others can reduce the activity of the formation. In neurons, there is an interaction of ascending and descending signals. The pulses are in constant circulation in the chains. Due to this, activity is maintained. It, in turn, is necessary to maintain the tone of the nervous system. In the event of the destruction of the formation, especially its upper sections, deep sleep occurs, although the afferent signals continue to flow into the cortex along other paths.

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