Anatomy & Organs

Brain – Structure, Function & Diseases


The brain (technically: cerebrum or encephalon) is the control center of the body, consisting of nerve tissue, in which information from the inside of the body is integrated with information from the outside world and processed. Together with the spinal cord, it forms the central nervous system (CNS) .

What is the brain

The human brain is the part of the central nervous system that is located in the skull. The crossing of the pyramidal tracts at the level of the large occipital foramen (foramen magnum) at the base of the skull marks the transition to the spinal cord.

The average adult male brain weighs 1400 g, and an adult female of the same height weighs 1300 g on average. According to current estimates, the brain consists of about 100 billion nerve cells and about as many glial cells.

Anatomy & Structure

Even at first glance, the division of the brain into two hemispheres is visible. The cerebral hemispheres are connected by several commissures. According to its history of development, the brain is divided into three parts:

The evolutionarily oldest part is the hindbrain, consisting of the medulla, pons and cerebellum. This is followed by the midbrain. The youngest part is the forebrain, which can be subdivided into the diencephalon and cerebrum.

The brain is surrounded by protective meninges. The cerebral cortex is heavily grooved to increase the surface area. The cerebral cortex is usually divided into 5 lobes: frontal lobe, parietal lobe, temporal lobe, occipital lobe and island lobe. In the brain itself, gray and white matter can be distinguished: The gray matter contains a large number of cell bodies. It occurs mainly superficially in the cerebral cortex, with only islands of gray matter found as nuclei or networks inside the brain.

Otherwise, the white substance, which mainly consists of nerve cell processes, predominates inside. In addition, there is a cavity system of 4 ventricles inside the brain. These are filled with cerebrospinal fluid, which has cushioning, immunological and signaling functions.

Functions & Tasks

The brain is a highly complex organ that performs a wide variety of tasks. It controls basic vegetative functions as well as top cognitive performance.

In the developmentally older sections, basic functions such as heart rate, breathing, sweating and vigilance are controlled. An interaction of older and younger structures is necessary for the generation of emotions, natural rhythms and memory functions. In the brain, the sensory impressions of all senses are processed and integrated, so that perceptions and sensory perceptions arise.

In particular, the very well developed sense of sight in humans occupies a considerable part of the cerebral cortex. The motor system within the brain allows for the control and planning of muscle activity. Without the motoric brain performance only a few reflexive movements via the spinal cord are possible.

The cerebrum is also considered the seat of human personality and intelligence. The brain needs a lot of energy in order to perform its comprehensive functions: When we are at rest, it is responsible for 15-20% of our energy consumption.


The spectrum of possible brain diseases is extremely wide. The first sign of a brain disorder is usually pain or dysfunction.

A very common clinical picture in industrialized nations is stroke , in which brain tissue is no longer adequately supplied with blood due to vascular occlusions or ruptured blood vessels. Nerve cells react very sensitively to a lack of oxygen and irretrievably perish after just a few minutes. Also common are epilepsies , which are caused by uncontrolled mass discharges of neurons.

Cancer can affect the brain either primarily in the form of brain tumors or secondarily through brain metastases . Inflammatory brain diseases (encephalopathies) are caused by viruses , bacteria , fungi or worms and often also affect the meninges in the form of meningitis . The etiology of multiple sclerosis , a chronic inflammatory disease in which the myelin sheaths of the CNS degenerate, is still poorly understood.

Degenerative brain diseases that are not yet fully understood also include Alzheimer’s dementia, Huntington ‘s disease and Parkinson’s disease . A craniocerebral trauma can end mildly with a slight concussion , but also with contusions, bleeding and a lethal increase in intracranial pressure. The irreversible failure of the brain is referred to as brain death and – ethically controversial – used as a definition of death.

Typical & common diseases

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.