Parasympathetic Dynamics

Overview The parasympathetic nervous system is one of the two major divisions of the autonomic nervous system. This parasympathetic system is responsible for regulating many unconscious functions, such as heart rate and digestion. It is composed of neurons located in both the brain and the peripheral nervous system that send their axons to target muscles, organs, and glands. The “Rest and Digest” System Activation of the parasympathetic system tends to have a relaxing effect on the body,...

Parasympathetic signaling plays a crucial role in regulating various physiological processes. It involves the release of acetylcholine (ACh) by parasympathetic neurons, which can have localized and short-lived effects. The majority of ACh released is rapidly inactivated at the synapse by the enzyme acetylcholinesterase (AChE), which hydrolyzes Ach into choline and acetate. Additionally, the tissue cholinesterase deactivates any ACh diffusing into the surrounding tissues. The effects of...

The parasympathetic division of the autonomic nervous system (ANS) regulates rest and digestion functions in the body. It works in opposition to the sympathetic division, promoting relaxation, conservation of energy, and digestion. The parasympathetic division consists of preganglionic fibers originating from specific cranial nerves (III, VII, IX, X) and the sacral spinal nerves (S2-S4). These fibers synapse with postganglionic neurons in the terminal ganglia, innervating various organs and...

The cranial part of the parasympathetic division plays a crucial role in regulating the visceral functions of the head and specific structures in the neck, thoracic, and abdominopelvic cavities. Preganglionic fibers of the parasympathetic division exit the brain through cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus), delivering parasympathetic output to the respective visceral structures. The vagus nerve (cranial nerve X) alone accounts for approximately 75...

Source: Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA It is rare nowadays that a whole year goes by without a major earthquake event wreaking havoc somewhere around the world. In some cases, like the 2005 Banda Ache earthquake in Indonesia, the damage involved large geographic areas and casualties in the six figures. In general, the number and intensity of earthquakes is not increasing, however, the vulnerability of the built environment is...