The sympathetic division can influence tissues and organs by releasing norepinephrine at peripheral synapses and distributing epinephrine and norepinephrine through the bloodstream. In times of crisis or stress, sympathetic activation occurs, which is regulated by sympathetic centers in the hypothalamus. As a result, sympathetic activation prepares the body for physical exertion, rapid ATP production, and heightened alertness, allowing individuals to respond effectively to challenging or threatening situations.

Physiology of Sympathetic Activation

During sympathetic activation, various physiological changes take place. The individual experiences increased alertness due to stimulation of the reticular activating system, leading to feeling "on edge." There is a surge of energy and euphoria, often accompanied by a temporary insensitivity to pain and a disregard for danger. The cardiovascular and respiratory centers in the brainstem become more active, resulting in increased heart rate, blood pressure, breathing rate, and depth of respiration.

Muscle tone is elevated, and the person may appear tense and may even begin to shiver. The mobilization of energy reserves occurs through the release of lipids by adipose tissue and the accelerated breakdown of glycogen in muscle and liver cells. These changes, along with the peripheral alterations, prepare the individual to cope with the stressful situation.

Sympathetic stimulation has longer-lasting and more widespread effects compared to parasympathetic stimulation. This effect is due to the extensive divergence of sympathetic postganglionic axons, allowing for simultaneous activation of multiple tissues. Additionally, norepinephrine lingers in the synaptic cleft longer than acetylcholine, and the release of epinephrine and norepinephrine from the adrenal medullae intensifies and prolongs the sympathetic responses.

タグ
Sympathetic ActivationNorepinephrineEpinephrineHypothalamusPhysiological ChangesReticular Activating SystemCardiovascular ResponseRespiratory ResponseMuscle ToneEnergy MobilizationStress ResponseSympathetic StimulationAdrenal Medullae

章から 19:

article

Now Playing

19.6 : Sympathetic Activation

自律神経系

3.0K 閲覧数

article

19.1 : 自律神経系

自律神経系

4.7K 閲覧数

article

19.2 : ANSの交感神経分割

自律神経系

1.0K 閲覧数

article

19.3 : 交感神経経路:交感神経鎖神経節

自律神経系

1.4K 閲覧数

article

19.4 : 交感神経経路:側副神経節と副腎髄質

自律神経系

892 閲覧数

article

19.5 : 交感神経シグナル伝達

自律神経系

523 閲覧数

article

19.7 : ANSの副交感神経部門

自律神経系

1.4K 閲覧数

article

19.8 : 副交感神経分裂の頭蓋部分

自律神経系

853 閲覧数

article

19.9 : 副交感神経シグナル伝達

自律神経系

1.1K 閲覧数

article

19.10 : 自律神経系の障害

自律神経系

340 閲覧数

JoVE Logo

個人情報保護方針

利用規約

一般データ保護規則

研究

教育

JoVEについて

Copyright © 2023 MyJoVE Corporation. All rights reserved