Structure
The brain is divided into several brain sections: Belong to the brain stem: The end and diencephalon of the brain together form the forebrain (prosencephalon), the former consisting of the cortex, the basal ganglia and the limbic system. The latter comprises the structures thalamus, epi-, sub- and hypothalamus as well as metathalamus. The brain stem of the brain is divided into the midbrain, the afterbrain and the extended medulla.
The midbrain is composed of the four mound plate (tectum), the midbrain hood (tegmentum) and the cerebral thighs (crura cerebri). The afterbrain contains the cerebellum (cerebellum) and the bridge (pons). Alternatively, the bridge, the cerebellum and the extended medulla can also be summarized as the rhombic brain (rhombencephalon).
If the brain is intact, the end brain, the cerebellum on the back and the afterbrain at the bottom are visible from the outside. By a conspicuous, middle furrow, the endbrain is divided in longitudinal direction into two equal parts, the cerebral hemispheres. In terms of location, the endbrain and diencephalon are found in the front and middle cranial fossa, while the brain stem – especially the cerebellum – is found in the posterior fossa.
The medulla oblongata as the structure of the brain continues seamlessly into the spinal cord. Inside, the brain encloses spaces that are filled with cerebrospinal fluid and form a coherent ventricle system. Their task is to protect the brain from vibrations.
- Endbrain = telencephalon
- Interbrain = diencephalon
- Brainstem = Truncus encephali
- Midbrain = Mesencephalon
- Afterbrain = Metencephalon from bridge (Pons) and cerebellum
- Extended medulla = Medulla oblongata
Blood supply to the brain
The blood supply of the brain can be divided into the front and rear circulation. The anterior circulation of the brain is fed by the right and left carotid arteries. The inner carotid artery (Arteria carotis interna) branches off from these two arteries, which in turn supply two vessels that lead to the brain: Arteria cerebri anterior (anterior cerebral artery) and Arteria cerebri media (middle cerebral artery).
These vessels supply the lateral part (anterior cerebral artery) and the middle part (posterior cerebral artery) of the cerebral hemispheres. All the vessels supplying the brain exist in two versions, since they are located on both the left and right sides of the body. The posterior circulation of the brain is formed by the two vertebral arteries (Arteria vertebralis), which unite to form the unpaired basilar artery (Arteria basilaris).
In its course to the brain, this artery gives off several branches to supply the brain stem and finally ends as the posterior cerebral artery (Arteria cerebri posterior), which supplies the posterior parts of the endbrain and partially the diencephalon with blood. These vessels of the brain are also doubled, with the exception of the basilar artery, which exists only once. Between the three cerebral arteries there is a coherent vascular system, the Circulus arteriosus cerebri Willisii (“arterial cerebral circulation Willisi”).
Such a system is called anastomosis system (anastomosis = net-like vascular connection) because of the connections between them. The cerebral cortex is the newest part of the brain in terms of developmental history. It is here that complex processes such as: processing, matching with other information and responding to these sensations with a targeted response (motor centers).
Other functions such as memory, thinking, learning and even emotions are all part of the cerebral functions. The deeper parts of the cerebrum, the so-called cerebral nuclei, are important switching points for motor and sensory stimuli. In a sense, they “channel” the information from the periphery and the other brain centers, and direct it to the cerebral cortex.
- Language
- Motor processes
- Differentiated sensor technology (tactile sensation, pressure sensation, pain…) and
- Sensory sensations
The diencephalon is responsible for the hormonal regulation of the body, for important autonomous processes (unconscious functions) and is also the switchboard for environmental stimuli that are called into consciousness by the cerebral cortex (“gateway to consciousness”). Hormones regulate a wide range of processes in the body such as metabolism, growth and reproduction.The main hormone regulating system is the hypothalamus-pituitary axis. This axis is responsible for ensuring that important growth and reproductive impulses reach the body where they can take effect. Important representatives here are the thyroid hormone, the growth hormone and the sex hormones. The diencephalon also regulates our biorhythm, our eating and drinking behavior (hunger and thirst) and our sexuality.
