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Wearable Sensors for Monitoring Exercise and Fatigue Estimation in Rehabilitation
Published in Manuel Cardona, Vijender Kumar Solanki, Cecilia E. García Cena, Internet of Medical Things, 2021
Maria J. Pinto-Bernal, Andres Aguirre, Carlos A. Cifuentes, Marcela Munera
Muscle fatigue is a transient and recoverable reduction in the force or power production in response to contractile activity. It is a symptom that makes it harder to move as normal [69]. It can originate at different motor pathway levels and is usually divided into central and peripheral components. Peripheral fatigue refers to exercise-induced processes that lead to a reduction in force production occurring at distal to the neuromuscular junction. Central fatigue refers to more centralized processes and can be defined as a progressive exercise-induced failure of voluntary activation of the muscle, which is not associated with the same reduction of maximum force obtained by stimulation [70]. Muscle fatigue is a commonly experienced phenomenon where people always feel tired and lack energy, resulting in limited performance and other strenuous or prolonged daily activities. Also, some people experience a dull aching in the muscle. It also increases and restricts daily life.
Biopotentials and Electrophysiology Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Figure 64.2 illustrates the continuum of electrophysiological signals from the (a) heart cells, (b) myocardium (the heart muscle), and (c) the body surface. Each cell in the heart produces a characteristic action potential [4]. The activity of cells in the sinoatrial node of the heart produces an excitation that propagates from the atria to the ventricles through well-defined pathways and eventually throughout the heart; this electric excitation produces a synchronous contraction of the heart muscle [5]. The associated biopotential is the ECG. Electric excitation of a neuron produces an action potential that travels down its dendrites and axon [4]; activity of a massive number of neurons and their interactions within the cortical mantle results in the EEG signal [6]. Excitation of neurons transmitted via a nerve to a neuromuscular junction produces stimulation of muscle fibers. Constitutive elements of muscle fibers are the single motor units, and their electric activity is called a single motor unit potential [7]. The electric activity of large numbers of single motor unit potentials from groups of muscle fibers manifests on the body surface as the EMG. Contraction and relaxation of muscles is accompanied by proportionate EMG signals. The retina of the eye is a multilayered and rather regularly structured organ containing cells called rods and cones, cells that sense light and color. Motion of the eyeballs inside the conductive contents of the skull alters the electric potentials. Placing the electrode in the vicinity of the eyes (on either side of the eyes on the temples or above and below the eyes) picks up the potentials associated with eye movements called EOGs. Thus, it is clear that biopotentials at the cellular level play an integral role in the function of various vital organs.
Homo Sapiens (“Us”): Strengths and Weaknesses
Published in Michael Hehenberger, Zhi Xia, Huanming Yang, Our Animal Connection, 2020
Michael Hehenberger, Zhi Xia, Huanming Yang
Neurotransmitters are chemical messengers that transmit signals across a synapse, such as a neuromuscular junction, from one neuron to another “target” neuron, muscle cell, or gland cell of the endocrine system. Examples of neurotransmitters are listed below: Glutamate is used at the great majority of fast synapses in the brain and spinal cord. Excessive glutamate release can overstimulate the brain and lead to excitotoxicity causing cell death resulting in seizures or strokes. Excitotoxicity has been implicated in certain chronic diseases, including ischemic stroke, epilepsy, amyotrophic lateral sclerosis, Alzheimer’s disease, Huntington disease, and Parkinson’s disease.46GABA (γ-aminobutyric acid) is used at the great majority of fast inhibitory synapses in virtually every part of the brain. Many sedative/tranquilizing drugs act by enhancing the effects of GABA.Acetylcholine was the first neurotransmitter discovered in the peripheral and central nervous systems. It is distinguished as the transmitter at the neuromuscular junction connecting motor nerves to muscles.Dopamine is playing a number of important functions in the brain. Dopamine regulates motor behavior and is related to pleasure as well as motivation. It plays a critical role in the reward system.Serotonin is a monoamine neurotransmitter. It is an interesting fact that 90% of serotonin is produced by, and found in the intestine. Serotonin also plays important roles in central nervous system neurons, regulating appetite, sleep, memory and learning, temperature, mood, behavior, muscle contraction, and function of the cardiovascular system and endocrine system. It may also play a role in depression.Norepinephrine is synthesized (from tyrosine) in the central nervous system and modulates the responses of the autonomic nervous system, the sleep patterns, focus and alertness.Epinephrine is also synthesized from tyrosine and released in the adrenal glands and the brainstem. It plays a role in sleep, influences the ability to be and stay alert, and the “fight-or-flight” response.Histamine works with the central nervous system (CNS), specifically the hypothalamus and CNS mast cells. Mast cells are a type of white blood cell, best known for their role in allergy and in important protective roles such as wound healing, angiogenesis (formation of new blood vessels), immune tolerance, and defense against pathogens.
The clinical effectiveness of custom-contoured seating for wheelchair users with neuromuscular disorders: a scoping review
Published in Assistive Technology, 2023
Neuromuscular disorders (NMD) is a broad term describing a group of conditions which progressively impair the neuromuscular system as a result of injury to or dysfunction of the central and/or peripheral nervous system, neuromuscular junction, or skeletal muscle (Haliloglu, 2022; Michel & Collins, 2020). Individuals with NMD may experience musculoskeletal deformities, such as scoliosis or hip dysplasia, excessive movements due to poor motor control regulation or spasticity, and postural instability of the trunk from paralysis, weakness or hypertonicity (Ham et al., 1998). This can limit their ability to counteract the effects of gravity on posture during sitting. Consequently, wheelchair users with NMD may experience secondary complications including heightened risk of pressure injuries, compromise to gastrointestinal and respiratory function, pain, discomfort and functional limitations to activity and participation (Long, 2020; Turner, 2001).
Effects of short-term sub-lethal diazinon® exposure on behavioural patterns and respiratory function in Clarias batrachus: inferences for adaptive capacity in the wild
Published in Chemistry and Ecology, 2022
Shubhajit Saha, Azubuike V. Chukwuka, Dip Mukherjee, Kishore Dhara, Aina O. Adeogun, Nimai Chandra Saha
The strong positive association between mucus secretion and loss of balance and average opercular movement within 48hrs of exposure to diazinon, indicates that the exhibition of loss of balance and increased opercular movement across exposure concentrations was explainable by the hypersecretion of mucus. While these observations are like stress responses observed during the 24 h exposure, the increased average opercular movement in elevated concentrations highlights the onset of respiratory distress due to cholinergic toxicity. This indicates the onset of the intermediate toxicity phase which is often marked by respiratory distress due to paralysis of respiratory muscles [65]. From the 72 h exposures correlogram, the positive relationship between average opercular movement showed strong positive association with erratic swimming movement indicating that with increased exposure time, erratic movements become more emphasised and rigorous due to the onset of respiratory distress. The strong positive association between AOM and erratic swimming behaviour highlights the post cholinergic phase. The muscular seizures and paralysis which precede death of the organism are the hallmark of excessive stimulation of nicotinic acetylcholine receptors at the neuromuscular junction [72].
Experimental and computational analysis of N-methylcytisine alkaloid in solution and prediction of biological activity by docking calculations
Published in Molecular Physics, 2022
Fanny C. Alvarez Escalada, Elida Romano, Silvia Antonia Brandán, Ana E. Ledesma
Nicotinic acetylcholine receptors are ligand-gated ion channels that mediate fast chemical neurotransmission at the neuromuscular junction and have various signalling characters in the central nervous system; human α4β2 is a nicotinic receptor of nicotinic subtype mostly abundant in the brain [41]. Nicotine is a plant alkaloid responsible for the addictive properties of tobacco; it binds with high affinity to the nicotinic acetylcholine receptors α4β2nAChRs and acts as a full agonist. Research works find new use of nAChR partial agonists for the treatment option by smoking cessation, such as cytosine, which diminishes nicotine support and reduces the pleasure from smoking [42]. To evaluate the basis for affinity binding and eventually identify the structural elements, supporting the receptor selectivity of the NMC to nAChRs receptor, we have structurally characterised complexes of that molecule with acetylcholine-binding protein (Ac-AChBP, PDB:4BQT) and human α4β2 nAChR (PDB: 5KXI) receptors. Full details, showing the ligand position in the binding site with NMC docked into each complex, are provided in Figure 6.