Collaterals
In anatomy , collaterals ( lat : con "together"; latus "side") are branches, side or secondary branches. They are found in the body both in the bloodstream and in the nervous system . The presence of collaterals or the formation of collaterals is also referred to as collateralization. The term is derived from the Latin name vas collaterale (secondary vessel, bypass vessel, alternative vessel; plural: vasa collateralia ).
Vascular system
Collaterals in the circulatory system secure the blood supply to a tissue area in the event of obstruction ( thrombosis , embolism ) or injury to individual blood vessels . They are connected to one another via anastomoses , so that one speaks of a collateral circulation . Without their presence, no surgical intervention would be possible, as this is always associated with a severing of blood vessels.
Vessels without collaterals and anastomoses are referred to as end arteries ; here an occlusion inevitably leads to the death of the tissue area ( infarction ). An example here would be the last branches of the intestinal arteries, which previously form a dense network, but no longer have any connection to their neighbors in the last few centimeters. An operation on the intestine with an injury to the vessels would later necrotize the intestine and cause it to die. If there are collaterals for a vessel that are not sufficient to supply the area in the event that the vessel is obstructed, then one speaks of a functional end artery for the vessel concerned (example: coronary vessels ).
With his work on the formation of the collateral circulation, the surgery professor Luigi Porta , who worked in Pavia, contributed to the development of modern vascular surgery in the 19th century.
Nervous system
Within the nervous system, neurites or axons run from one nerve cell to another. In this way, the axons often give off branches or side branches called collaterals . In this way, other nerve cells in different core areas can be reached.
This means that the current excitation of a neuron is transmitted as a signal to several other neurons. This divergence of signal transmission occurs in almost all interconnection patterns in the nervous system . It is found in the CNS both at the level of a segment in the spinal cord and in all regions of the brain .
Peripheral nerves lead nerve fibers, for example axons of motor neurons in the anterior horn of the spinal cord, efferent to the muscles . The excitation of a single motor neuron reaches several different muscle fibers of a muscle via its axon collaterals . All of these are then activated together - via their motorized end plates ; together they form a motor unit .
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Individual evidence
- ↑ The adjective collateralis (adjacent, side) is of Middle Latin origin and appears for the first time around 1100 . Although the noun "Kollaterale" is derived from the neuter form of the adjective, the feminine form commonly used ("the Kollaterale") is the only one recommended by the Duden today: Kollaterale , duden.de
- ↑ Luigi Porta: Delle alterazioni patologiche delle arterie per la legatura e la torsione. Milan 1845.
- ↑ Barbara I. Tshisuaka: Porta, Luigi. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 1176.