Neuroanatomy

The neuroanatomy is a science that examines the structure of the nervous system. It is a branch of neurobiology as well as a specialized field of systematic anatomy and has in neurophysiology and neurochemistry sister disciplines. Closely related to the neuroanatomy is also the neuropathology, which examines the structural changes in the nervous system in pathological processes.

The neuroanatomy is concerned with the size, location, wording and structure of the nervous system of humans and animals. The sub-discipline of comparative neuroanatomy is on relationships between the brain or spinal cord structures of various animal groups and can thus make statements about the evolution of the nervous system.

History of Neuroanatomy

The role of the nervous system for the transmission of information was of Greek philosophers and physicians of antiquity rather guessed than known. In the concepts of antiquity nerves were usually held for hollow Leitröhren for the pneuma, a kind of life-giving substance that should be formed in the brain from the blood. The brain itself was very differently: sometimes it was considered the center of the mind and the soul, sometimes it should only be used to cool or produce mucus blood. It was not until around the 3rd century BC came to the Alexandrian school anatomists such as Herophilus of Chalcedon and Erasistratus of course that laid through numerous sections also to people the basics of scientific and observational neuroanatomy. Legal dedicated findings - also on physiological relationships - was obtained primarily from Erasistratus, the case was based on the vivisection of animals. He already recognized the differences between motor and sensory nerves and the brain was divided into its macro anatomical proportions. Galen, a Greek physician of the high Roman Empire, amassed the knowledge of his time and also introduced himself by sections, but only on animals, so many fallacies got lost in his writings. As he was for nearly 1,300 years as the undisputed authority in the field of anatomy, these errors remain undetected as long.

Subject

The treated article is the nervous system, its geweblichen and cellular structures. A morphological feature of this system is the connectivity, ie the principle that the individual cells with each received multiple connections that allow their interaction and define. The smallest functional unit of the nerve cell ( neuron also ), forming processes ( dendrites and axons), through which they get in contact with other neurons via synapses and transmit information as electrical potentials. Neurons have a particularly easy modulable membrane potential and are therefore rapidly and repeatedly irritable. About the synapse itself the excitation by chemical messengers called neurotransmitters is passed.

A distinction is made between the central (brain and spinal cord) and the peripheral portion (nerve ) of the nervous system. A distinction is " autonomous " vegetative nervous system between the " somatic " ( arbitrariness ) and the nervous system. These organizations serve more systematics, where the subsystems described are not truly independent of each other units. The nervous tissue of higher animals is in cell-rich gray matter and fiber (cell protrusion- ) rich white substance divided. The cellular composition, the so-called cytoarchitecture it differs significantly in different portions of the nervous system and reflects the feature.

Embryonic develop all the components of the nervous system from the outer germ layer, the ectoderm. Only a portion of the precursor cells differentiated from nerve cells, others become specialized supporting tissue, the glia.

Particularly important for understanding the neuroanatomical relationships to each other, the spatial ( topical ) relations between individual sections. Defined so that the curve is ( the projection) of the webs of a cell population to another intended. These run not arbitrary, but are subject to a clear structure, in which is formed from the projections of many nerve cells Railways ( tractus, fasciculi, lemnisci etc. ) can be distinguished. However, over the genetically predetermined basic structure, the nervous system has a high plasticity, so that the formation of anatomical fine structure is also determined by imprinting and learning.