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Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
The fibres of the parasympathetic nervous system originate in the cranial nerves and from the lower end of the spinal cord (the sacral region). The 12 cranial nerves have the cells of origin in the brainstem. The third, seventh, ninth and tenth cranial nerves all contain parasympathetic fibres. The tenth cranial nerve or the vagus nerve is the principal parasympathetic nerve and its stimulation causes a slowing of the heart amongst many other effects, such as those on the stomach and stomach secretions, oesophagus and the small airways of the lungs.
Triboelectric Nanogenerators
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Nanogenerators, 2023
Ritvik B. Panicker, Ashish Kapoor, Kannan Deepa, Prabhakar Sivaraman
Obesity is a very significant disease that affects the world (Singh et al., 2013). Vagus nerves are responsible for the transfer of signals to and from the brain and other parts of the body. The stimulation of the vagus nerves can help reduce weight. Yao et al. (2018) reported a stimulation device eliminating the need for a battery. The vagus nerves were stimulated using a flexible TENG positioned on the abdomen. The biological process that is responsible for the memory and learning of an individual is termed synaptic plasticity. The synaptic activity alters the strength of the synaptic signals. Guan et al. (2020) demonstrated an e-skin based on wireless stimulation of the nerves and powered by TENG. It comprises a photosensitive flexible perovskite unit. This kind of skin TENG harnesses the biomechanical form of energy from bodily movements.
Electrical Brain Stimulation to Treat Neurological Disorders
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
Vagus nerve stimulation (VNS) works through a device implanted under the skin that sends electrical pulses through the left vagus nerve, half of a prominent pair of nerves that run from the brainstem through the neck and down to each side of the chest and abdomen. The vagus nerves carry messages from the brain to the body’s major organs (e.g., heart, lungs, and intestines) and to areas of the brain that control mood, sleep, and other functions (see Figure 6.11).
Mechanism of peripheral nerve modulation and recent applications
Published in International Journal of Optomechatronics, 2021
Heejae Shin, Minseok Kang, Sanghoon Lee
Vagus nerve, one of the cranial nerves, is an important component of the parasympathetic branch of the autonomic nervous system that controls involuntary movements of the heart, lungs, adrenal glands, and digestive tract.[73] Therefore, vagus nerve stimulation is effective in treating and alleviating diseases such as heart failure, epilepsy, and depression as a bioelectronic medicine field.[74–76] However, since these various functions are regulated by the vagus nerve, selective nerve stimulation to produce only the desired effect is essential. As shown in Figure 4(a), optogenetic stimulation and electrical stimulation were applied to the right vagus nerve to compare the two stimulation methods.[77] The vagus nerve is a mixed nerve with efferent and afferent fibers. Because these researchers expressed the opsin ChR2 only in efferent fibers (GFP+), optogenetic stimulation stimulated only efferent fibers, whereas electrical stimulation stimulated not only efferent fibers, but also afferent fibers (PGP9.5+) using hook electrodes. The right vagus nerve controls function mainly related to the heart. Both optogenetic stimulation and electrical stimulation decreased heart rate during normal right vagus nerve stimulation, but electrical stimulation decreased heart rate only after right vagotomy (RVNx) since it also stimulated afferent fibers transmitting the signal to the brain. In this experiment, hook electrodes, which do not have selective stimulation capability, were used for stimulation afferent fiber, so, it cannot be concluded that optogenetic stimulation is superior to electrical stimulation. However, it has been shown that optogenetic stimulation with excellent selectivity is suitable for nerves containing fascicles responsible for multiple functions, such as the vagus nerve.