The human brain is unique in its anatomy. The brain consists of billions of nerve cells that are interconnected in complex ways. Nevertheless, the brain can be easily divided into different components and areas, some of which can be assigned certain functions. This article gives you an overview of the anatomy of the human brain.
Rough division of the brain into 5 parts
The human brain anatomy can be described in different ways. First of all, it makes sense to consider the brain (encephalon) divided into five main regions. These five areas of the brain are evident to varying degrees in all vertebrates:
- End brain, often called cerebrum (telencephalon)
- Diencephalon
- Midbrain (mesencephalon)
- Hindbrain (metencephalon)
- Hindbrain (myelencephalon, also: oblong medulla, medulla oblongata)
The name of these main regions is based on the simple brain anatomy of lower vertebrates, in which the regions lie one behind the other in a tubular shape. In comparison, the human brain is more complicated, but these five parts of the brain are still clearly visible despite further evolutionary development. So that you get an idea of the human brain, we will go into the five brain regions mentioned in more detail below and describe further possible classifications within the brain anatomy.
The endbrain and diencephalon form the forebrain (prosencephalon)
The forebrain consists of the hindbrain and the diencephalon. The large cortex of the endbrain (cerebral cortex, cortex cerebri) is particularly characteristic of human brain anatomy. Its characteristic convolutions (gyri) and furrows (sulci) result in a significantly increased surface area, which means that the volume can remain relatively small.
The endbrain is composed of two hemispheres, which are separated from each other by the fissure "fissura longitudinalis cerebri". Deeper inside, however, they are connected to each other by the so-called beam (corpus callosum). A frontal section of the brain shows the gray and white matter of the hemispheres.
The image "Brain structure in section" shows the brain anatomy in such a section. The outer gray matter consists mainly of the cell bodies of the nerve cells and the inner white matter consists of the nerve fibers.
The 4 lobes of the endbrain
Both hemispheres can be divided into four lobes based on certain grooves:
- Forehead lobe (frontal lobe)
- Parietal lobe (lobus parietalis)
- Occipital lobe (occipital lobe)
- Temporal lobe (temporal lobe)
As the name suggests, the frontal lobe is located at the front of the forehead. The parietal lobe borders the frontal lobe from behind and extends to the occipital lobe at the back of the head. The temporal lobe is located laterally below the parietal lobe. The position of the brain lobes corresponds to the similarly named bones of the brain skull, as shown in the picture "Skull Bone Anatomy".
Functional areas of the cortex
The human cortex cerebri is particularly highly developed. It is for properties
responsible for making people what they are. Certain areas of the cortex can be assigned certain functions. For example, there are areas in the temporal lobe that process information from the sense of hearing. The primary visual cortex, which handles some of the visual information processing, is located in the occipital lobe.
The parietal lobe has areas of body perception that convey skin, organs, muscles and joints. The motor speech center and other motor areas are located in the frontal lobe. There are also areas that are involved in personality formation.
The structure of the midbrain (diencephalon)
Between the hemispheres of the endbrain lies the diencephalon with the following structures:
- Thalamus
- Epithalamus with epiphysis
- Hypothalamus with neurohypophysis
- Subthalamus
The thalamus serves as a control center through which almost all information flowing to the cortex passes. It is also called the “gateway to consciousness”. You can see the location of the thalamus in the image “Brain - Sagittal Section”. This shows the brain anatomy in a sagittal section, i.e.
in the side view. The epithalamus, located on the thalamus, houses the pineal gland (epiphysis). This forms melatonin, known as the sleep hormone, and is therefore involved in the sleep-wake rhythm.
The hypothalamus lies below the thalamus and is connected to the pituitary gland. The pituitary gland, which is responsible for hormonal control, is divided into the posterior lobe (neurohypophysis) and the front lobe (adenohypophysis). However, the adenohypophysis, which is made up of glandular cells, is not part of the brain. The hypothalamus controls, among other things, the autonomic nervous system, but is also involved in emotional life.
The limbic system consists of structures of the forebrain
The limbic system represents another functional division within the brain anatomy.
It includes brain structures that are responsible for controlling emotions. In addition, the limbic system takes on important functions in learning and is in contact with the hypothalamus. It covers the bar that connects the two hemispheres. The limbic system includes:
- Structures of the olfactory brain
- Almond nucleus (amygdala)
- Hippocampus
- Cingulate gyrus
- Parahippocampal gyrus
Due to the close relationship between the olfactory brain and the other structures of the limbic system, smells, memories and emotions are often linked to one another. The amygdala plays an essential role in the development of fear, while the hippocampus is important for learning processes and is involved in aggressive and motivational behavior.
The anatomy of the brainstem and cerebellum
The midbrain, the bridge (pons) of the hindbrain and the hindbrain form the brainstem (truncus cerebri). The nuclei of the cranial nerves, fiber bundles of the hypothalamus and long pathways of nerve cells are located there.
All three parts of the brainstem are connected to the cerebellum, which rests on the brainstem. The cerebellum is made up of the worm (Vermis cerebelli) and also two hemispheres (Hemispheria cerebelli). Together with the pons, it forms the hindbrain and is responsible for balance, the tension of the muscles and the coordination of muscle activity.
With the hindbrain, the brainstem finally merges into the spinal cord, whereby the gray and white matter are rearranged. In terms of evolutionary history, the brainstem is the oldest part of human brain anatomy.
