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Fatigued
Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve after rest or sleep, or occurs independently of physical or mental exertion, it may be a symptom of a medical condition that may become severe or progressive. Fatigue can be a feature of a mental disorder such as depression; may be associated with conditions of chronic pain such as fibromyalgia; it may also feature in conditions of chronic low-level inflammation, and be a disease-related symptom in many other conditions. Fatigue often has no known cause, and is recognised as being very complex in nature. Fatigability describes a susceptibility to fatigue. Physical fatigue results from muscle fatigue brought about by intense physical activity. Mental fatigue results from prolonged periods of cognitive activity which impairs cognitive ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep Deprivation
Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity. Acute sleep deprivation is when an individual sleeps less than usual or does not sleep at all for a short period of time – usually lasting one to two days. Chronic sleep deprivation means when an individual routinely sleeps less than an optimal amount for ideal functioning. Chronic sleep deficiency is often confused with the term insomnia. Although both chronic sleep deficiency and insomnia share decreased quantity and/or quality of sleep as well as impaired function, their difference lies in the ability to fall asleep. Sleep deprived individuals are able to fall asleep rapidly when allowed but those with insomnia have difficulty falling asleep. The average adult needs seven or more hours of sleep per night to mainta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ego Depletion
Ego depletion is the idea that self-control or willpower draws upon a limited pool of mental resources that can be used up (with the word "ego" used in the psychoanalytic sense rather than the colloquial sense). When the energy for mental activity is low, self-control is typically impaired, which would be considered a state of ego depletion. In particular, experiencing a state of ego depletion impairs the ability to control oneself later on. A depleting task requiring self-control can have a hindering effect on a subsequent self-control task, even if the tasks are seemingly unrelated. Self-control plays a valuable role in the functioning of the self on both individualistic and interpersonal levels. Ego depletion is therefore a critical topic in experimental psychology, specifically social psychology, because it is a mechanism that contributes to the understanding of the processes of human self-control. There have both been studies to support and to question the validity of ego-de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Fatigue
Muscle fatigue is the decline in ability of muscles to generate force. It can be a result of vigorous exercise but abnormal fatigue may be caused by barriers to or interference with the different stages of muscle contraction. There are two main causes of muscle fatigue: the limitations of a nerve’s ability to generate a sustained signal (neural fatigue); and the reduced ability of the muscle fiber to contract (metabolic fatigue). Muscle contraction Muscle cells work by detecting a flow of electrical impulses from the brain which signals them to contract through the release of calcium by the sarcoplasmic reticulum. Fatigue (reduced ability to generate force) may occur due to the nerve, or within the muscle cells themselves. Neural fatigue Nerves are responsible for controlling the contraction of muscles, determining the number, sequence and force of muscular contraction. Most movements require a force far below what a muscle could potentially generate, and nervous fatigue is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directed Attention Fatigue
Directed attention fatigue (DAF) is a neuro-psychological phenomenon that results from overuse of the brain's inhibitory attention mechanisms, which handle incoming distractions while maintaining focus on a specific task. The greatest threat to a given focus of attention is competition from other stimuli that can cause a shift in focus. This is because one maintains focus on a particular thought by inhibiting all potential distractions and not by strengthening that central mental activity. Directed attention fatigue occurs when a particular part of the brain's global inhibitory system is overworked due to the suppression of increasing numbers of stimuli. This temporary condition is not a clinical illness or a personality disorder. It is rather a temporary fatigue of the inhibitory mechanisms in the brain. According to inhibition theory, it is natural for one to alternate between periods of attention and distraction. Although one's efforts may involve very different tasks, each incom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Sclerosis
Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Specific symptoms can include double vision, blindness in one eye, muscle weakness, and trouble with sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms). In the relapsing forms of MS, between attacks, symptoms may disappear completely, although some permanent neurological problems often remain, especially as the disease advances. While the cause is unclear, the underlying mechanism is thought to be either destruction by the immune system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Action Potential
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and in some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells. In neurons, action potentials play a central role in cell-cell communication by providing for—or with regard to saltatory conduction, assisting—the propagation of signals along the neuron's axon toward synaptic boutons situated at the ends of an axon; these signals can then connect with other neurons at synapses, or to motor cells or glands. In other types of cells, their main function is to activate intracellular processes. In muscle cells, for example, an action potential is the first step in the chain of events l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuromuscular Disease
A neuromuscular disease is any disease affecting the peripheral nervous system (PNS), the neuromuscular junction, or skeletal muscle, all of which are components of the motor unit. Damage to any of these structures can cause muscle atrophy and weakness. Issues with sensation can also occur. Neuromuscular diseases can be acquired or genetic. Mutations of more than 500 genes have shown to be causes of neuromuscular diseases. Other causes include nerve or muscle degeneration, autoimmunity, toxins, medications, malnutrition, metabolic derangements, hormone imbalances, infection, nerve compression/entrapment, comprised blood supply, and trauma. Signs and symptoms Symptoms of neuromuscular disease may include numbness, paresthesia, muscle weakness, muscle atrophy, myalgia (muscle pain), and fasciculations (muscle twitches). Causes Neuromuscular disease can be caused by autoimmune disorders, genetic/hereditary disorders and some forms of the collagen disorder Ehlers–Dan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In Computer Science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction. Clinical uses EMG testing has a variety of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mental Processes
Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, intelligence, the formation of knowledge, memory and working memory, judgment and evaluation, reasoning and computation, problem solving and decision making, comprehension and production of language. Imagination is also a cognitive process, it is considered as such because it involves thinking about possibilities. Cognitive processes use existing knowledge and discover new knowledge. Cognitive processes are analyzed from different perspectives within different contexts, notably in the fields of linguistics, musicology, anesthesia, neuroscience, psychiatry, psychology, education, philosophy, anthropology, biology, systemics, logic, and computer science. These and other approaches to the analysis of cognition (such as embodied cognition) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Contraction
Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state. For the contractions to happen, the muscle cells must rely on the interaction of two types of filaments which are the thin and thick filaments. Thin filaments are two strands of actin coiled around each, and thick filaments consist of mostly elongated proteins called myosin. Together, these two filaments form myofibrils which are important organelles in the skeletal muscle system. Muscle contraction can also be described based on two variables: length and tension. A muscle contraction is described as isometric if the muscle tension changes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Of Consciousness
An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousness or alertness may be classed as lethargy; someone in this state can be aroused with little difficulty. People who are obtunded have a more depressed level of consciousness and cannot be fully aroused. Those who are not able to be aroused from a sleep-like state are said to be stuporous. Coma is the inability to make any purposeful response. Scales such as the Glasgow coma scale have been designed to measure the level of consciousness. An altered level of consciousness can result from a variety of factors, including alterations in the chemical environment of the brain (e.g. exposure to poisons or intoxicants), insufficient oxygen or blood flow in the brain, and excessive pressure within the skull. Prolonged unconsciousness is unde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
