Brain stem – function, structure & symptoms

Brainstem

The doctor describes the brain stem – truncus encephali – as that area of ​​the human brain that is located directly below the human diencephalon . These include the pons, the elongated spinal cord and also the midbrain .

Definition

The brainstem is the section directly below the diencephalon, which includes all parts of the brain and is formed from the second and third cerebral vesicles. According to one definition, the cerebellum is also one of them, although for historical reasons there is no affiliation with the truncus encephali.

Anatomy

The brainstem is about the size of a thumb and represents the junction of the sections of the central nervous system. Just behind the brainstem is the cerebellum; above lies the cerebrum and diencephalon. The brainstem itself includes the human midbrain, pons and also the extended spinal cord.

The midbrain has a size of around two centimeters and divides the hood, the two cerebral peduncles and the quad. The most important core areas are the reticular formation, which have a black substance and a red core.

The bridge consists of the bridge cap, the medullary velum and the bridge foot. The extended spinal cord consists of the hood and the rear or front area and is structured in three layers. On the front face run the pyramids and their orbits; On the other hand, the olives are on the side and the diamond pit at the back. Inside is the vomiting center.

The brainstem itself is a pool for countless neurotransmitters and chemical substances. There is also a high iron content in the brainstem (detectable by means of the Prussian blue reaction) .

Function

All core areas of the cranial nerves pass through the brainstem. These are, for example, the pathways of the pyramidal and extrapyramidal system, the pathways of protopathic and epicritic sensitivity, and the cerebellar side cord pathways. The cranial nerves are mainly located in the rhombencephalon area; the arrangement is reminiscent of columns.

All parts that belong to the brainstem are responsible for control, regulation, coordination and modulation. The nuclei are a kind of switching station and are responsible for controlling numerous bodily functions. The brainstem controls blood pressure and heart rate, regulates breathing and sweating.

Furthermore, the brainstem is also responsible for sleeping and waking; even reflexes such as swallowing, vomiting or coughing are controlled. In the center is the so-called formatio reticularis, which also contains the raphe nuclei.

There are also ten cranial nerves in the brainstem, which are responsible for regulating balance. Even the control of the facial muscles and also the eye muscles , the taste and hearing impressions are transported via these brain nerves. The brainstem is also responsible for the coordination of muscle movements.

Diseases

  • Locked-In-Syndrom
  • Wallenberg Syndrome
  • Benedict Syndrome
  • Weber syndrome
  • Babinski-Nageotte-Syndrome
  • Dandy-Walker-Malformation
  • Chiari-Malformation
  • Astrozytom

Brainstem infarction is one of the most significant diseases that can affect the brainstem. The most severe form, the so-called locked-in syndrome, causes an almost complete paralysis of the affected person, who can usually only perform vertical eye movements. However, the patient does not have any depressed level of consciousness; he is fully conscious and can sometimes understand even complex connections. In milder variants of brainstem infarction, however, a complete cure can be achieved.

Wallenberg Syndrome is another brainstem disorder in which the spinal cord suffers from an undersupply of blood. For this reason, the affected person complains of swallowing, emotional and movement disorders.

Benedict syndrome is damage to the midbrain. In that case, so-called functional disorders occur, which are mainly noticeable on the contralateral side of the body. The pupil of the affected person is fixed to light; the patient also reports seeing double vision.

Other diseases that affect the brainstem are Weber syndrome and Babinski-Nageotte syndrome. In those cases, those affected repeatedly suffer from neurological deficits. Those are primarily perceived on the contralateral side.

The Dandy-Walker malformation and the Chiari malformation also belong to diseases of the brainstem. The Chiari malformation is a malformation that is mainly caused by a misunderstanding of size; that misunderstanding arose between the posterior fossa and the metencephalon. The symptoms usually appear between the ages of 10 and 40. At the beginning, the patient still complains of pain in the neck and back of the head; as the disease progresses, visual and balance disorders are added.

If there is a fetal developmental disorder that has manifested itself in the cerebellum, doctors speak of a Dandy-Walker malformation. This occurs – in the case of eye movement disorders or spasticity – already in the first year of life.

Sometimes a tumor can form in the brainstem. The most common type of tumor that can occur in that region is astrocytoma. Symptoms are speech and vision disorders , spastic paresis, headaches and nausea with vomiting .

Dorothy Farrar

Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.

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