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Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The peripheral nervous system has two main subdivisions (Figure 1.6): The somatic nervous system, concerned with sensory input to the central nervous system and with motor output to skeletal muscle.The autonomic nervous system, concerned with the control of visceral functions such as heart rate, digestion, respiration, and perspiration. The autonomic nervous system has two main subdivisions: (i) the sympathetic nervous system, involved in the “fight-or-flight” response that mobilizes the body to respond to stressful or threatening conditions, and (ii) the parasympathetic nervous system, concerned with activities of the body at rest, such as digestion and waste elimination. Most organs and systems of the body receive both sympathetic and parasympathetic stimulation acting in opposition, thereby providing a more effective, finer control.
Biosensors and Human Behavior Measurement
Published in Krzysztof Iniewski, Biological and Medical Sensor Technologies, 2017
Studies regarding the anatomy and physiology of the autonomic nervous system (ANS) such as Ref. [9] have found links proving that emotional state directly affects the function of the ANS. The ANS innervates organs all through the body. Texts such as Ref. [9] explain the ANS by dividing it into two sections: the sympathetic nervous system, which triggers fight or flight responses, and the parasympathetic nervous system, which triggers rest and digest responses. The parasympathetic system triggers reactions in organs basically to divert energy toward digestion, while the sympathetic system diverts energy toward skeletal muscles for a fight or flight response. This is part of the body’s overall effort to maintain homeostasis. Krassioukou and Weaver [9] list what organs are innervated by the ANS and what responses the two sections trigger.
Cardiovascular System:
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
There are two types of cardiac muscle cells—the contractile cells, which create the muscle force, and the autorhythmic cells, which include the pacemaker cells and the conducting system (Figure 1.4). The heart requires no outside signal to contract. The action potential or nervous impulse is initiated in the pacemaker regions of the heart (the sinoatrial or the S-A node and the A-V node). It is then spread through the specialized conducting system (the bundle of His and the Purkinje fibers, which can also initiate action potentials). Each of these pacemaker regions depolarize themselves at different rates, with the S-A node exciting at a rate of 70 beats per minute, the A-V node exciting at a rate of 40 beats per minute, and the bundle of His and Purkinje fibers exciting at a rate of 20–30 beats per minute. Under normal circumstances, the action potential is initiated in the right atrium, by the S-A node, which has the fastest rate of pacemaker cycling (or action potential depolarization). As the impulse spreads to the other pacemaker regions, it causes them to excite before they have a chance to depolarize themselves. Thus, the heart rate (typically 70 beats per minute) is controlled by the S-A node. If this node stopped functioning, the A-V node (the next fastest depolarizing rate) would then control the heart rate (which would drop to about 40 beats per minute). At rest, the parasympathetic system is dominant and acts to suppress the heart rate (from an intrinsic rate of approximately 100 beats per minute, down to about 70 beats per minute). During exercise, when the sympathetic system is dominant, the heart rate increases and the conduction time is quickened.
Cardiovascular response to whole-body vibration on an automobile seat
Published in Ergonomics, 2021
Cor-Jacques Kat, Jacques Schalk Jooste, Catharina Cornelia Grant, Piet J. Becker, Pieter Schalk Els
Most physiological parameters are linked to the autonomic nervous system. The autonomic nervous system maintains internal homeostasis within the human body at a subconscious level via the parasympathetic and sympathetic branches. The parasympathetic branch is responsible for the resting state, controlling the body processes during ordinary situations (‘Rest and Digest’). In general, parasympathetic responses increases heart rate variability (HRV), slow heart rate (HR), reduce blood pressure, stimulate the digestive tract to process food and use energy to restore and build tissue (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology 1996; Cannon 1939; Hall 2006). The sympathetic branch is responsible for ‘Fight or Flight’ reactions during stressful situations. Depending on the specific balance between parasympathetic and sympathetic cardiac influence, sympathetic branch activity may decrease HRV, increase HR and the force of cardiac contractions, increase muscle strength and causes the body to release stored energy (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology 1996; Cannon 1939; Hall 2006).
Stress and burnout among attending and resident physicians in the ED: a comparative study
Published in IISE Transactions on Healthcare Systems Engineering, 2020
Vishnunarayan Girishan Prabhu, Kevin Taaffe, Ronald Pirrallo, Dotan Shvorin
HRV, which is the change in the time between successive heartbeats, is a reliable reflection of many physiological factors (Acharya et al., 2006). It has been used as a quantitative marker to understand the interplay between the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is our fight and flight response, whereas the parasympathetic is the rest and digest response. The former activates during high stress, anxiety, or fear while the latter helps the body to maintain homeostasis (McCorry, 2007). Although HRV can be analyzed and interpreted using a variety of methods, the most common and reliable methods used are time domain and frequency domain metrics (Malik et al., 1996). Hence for analysis, we considered both time domain and frequency domain metrics of the HRV.
Bodies in mind: using peripheral psychophysiology to probe emotional and social processes
Published in Journal of the Royal Society of New Zealand, 2021
Gina M. Grimshaw, Michael C. Philipp
Afferent inputs are complemented by two efferent systems that project from the brain to the body: the autonomic system and the somatic system (see reviews by Hamill et al. 2012; Levenson 2014; Ernsberger and Rohrer 2018). The autonomic system innervates primarily internal organs, the skin, and the pupil, modulating the body’s use of resources to promote survival. The system has two branches. The sympathetic system mobilises resources to deal with challenges (fight or flight); increasing heart rate to move oxygen to muscles, increasing sweat production to reduce friction and maintain body temperature, and dilating the pupils to increase visual sensitivity. The parasympathetic system preserves resources (rest and digest); decreasing heart rate, slowing respiration, and directing blood flow to core digestive functions. Both systems are innervated by brainstem ganglia, but their actions are modulated by inputs from multiple brain networks that are involved in emotional and social processes, including rich connections amongst the amygdala, insula, anterior cingulate and prefrontal cortex (Hagemann et al. 2003; Hänsel and von Känel 2008). Most organs within the autonomic system are innervated by both sympathetic and parasympathetic efferents. The relationship between systems is often reciprocal, with the parasympathetic system acting to regulate sympathetic activation. However, the two systems are under independent cortical control, making it possible in some situations to activate (or deactivate) sympathetic and parasympathetic systems simultaneously (Koizumi and Kollai 1981; Saper 2002; Paton et al. 2005).