Energy!
No other organ in our body consumes as much energy as the brain. In humans, it consists of around 86 billion neurons, and although a lot of energy is used for communication via electrical impulses on the membrane, the processes inside the cell also consume a considerable amount. This energy is supplied by certain cell organelles called mitochondria, which form the main powerhouse of all body cells. But unlike other cells, neurons are sometimes extremely long, with Dendrite trees and axons that can grow to a meter or more in length. And even their furthest end, the terminal button, needs energy because it has to release its messenger substances at the synapse.
These four compartments of the Neuron – dendrites, cell body, axon, and presynapse – have different supply requirements, but all need energy immediately. In the case of axons, for example, special Glial cells called Oligodendrocytes are recruited. We actually know them more as accelerators of the action potential, but this is probably more of a side effect of their primary evolutionary task: supplying energy.
The Homeo-Hirn research network is investigating how the cell ensures the supply in all its compartments and, despite all the diverse requirements, still maintains the energetic balance, Homeostasis. This is done partly with specially developed methods and always with a view to diseases of the nervous system – for example, after strokes or multiple sclerosis.
The text Energy Supply of Neurons by Nora Schultz provides an initial overview.
Dendrite
Tree-like branching area of nerve cells whose extensions act as a kind of antenna for receiving electrical impulses from other cells.
Synapse
A synapse is a connection between two neurons and serves as a means of communication between them. It consists of a presynaptic region – the terminal button of the sender neuron – and a postsynaptic region – the region of the receiver neuron with its receptors. Between them lies the synaptic cleft.
Neuron
A neuron is a specialized cell in the nervous system that is responsible for processing and transmitting information. It receives signals via its dendrites and transmits them via its axon. Transmission occurs electrically within the neuron and, between neurons, usually chemically via synapses.
Glial cells
Glia cells are the second largest group of cells in the brain after neurons. For a long time, they were considered inactive elements of the brain, referred to as "nerve cement." Today, we know that the different types of glia cells (astrocytes, oligodendrocytes, and microglia in the CNS; Schwann cells in the PNS) perform clearly defined tasks in the nervous system. For example, they respond to pathogens, play an important role in nourishing nerve cells, and insulate nerve fibers. They account for slightly more than 50 percent of the brain's cells, compared to neurons.
Oligodendrocytes
Cells of the central nervous system that form the myelin sheath around nerve cells, thereby increasing their conduction velocity. They belong to the glial cells.
Homeostasis
Homeostasis is the ability of an organism to maintain internal conditions such as metabolism, body temperature, blood pressure, etc. at a relatively constant level. The maintenance of homeostasis is controlled by the autonomic nervous system, meaning that humans cannot directly influence its regulation at will.