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Shiver
Shivering (also called shuddering) is a bodily function in response to cold and extreme fear in warm-blooded animals. When the core body temperature drops, the shivering reflex is triggered to maintain homeostasis. Skeletal muscles begin to shake in small movements, creating warmth by expending energy. Shivering can also be a response to fever, as a person may feel cold. During fever, the hypothalamic set point for temperature is raised. The increased set point causes the body temperature to rise (pyrexia), but also makes a person feel cold until the new set point is reached. Biological basis Located in the posterior hypothalamus near the wall of the third ventricle is an area called the primary motor center for shivering. This area is normally inhibited by signals from the heat center in the anterior hypothalamic-preoptic area but is excited by cold signals from the skin and spinal cord and becomes activated when the body temperature falls even a fraction of a degree below a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postanesthetic Shivering
Postanesthetic shivering (PAS) is shivering after anesthesia. Description and treatment Postanesthetic shivering is one of the leading causes of discomfort in patients recovering from general anesthesia. It usually results due to the anesthetic inhibiting the body's thermoregulatory capability, although cutaneous vasodilation (triggered by post-operative pain) may also be a causative factor. First-line treatment consists of warming the patient; more persistent/severe cases may be treated with medications such as tramadol, pethidine, clonidine, and nefopam, which work by reducing the shivering threshold temperature and reducing the patient's level of discomfort. As these medications may react and/or synergize with the anesthetic agents employed during the surgery, their use is generally avoided when possible. The anesthetic ketamine can also be used to manage postanesthetic shivering. Intensity The intensity of PAS may be graded using the scale described by Crossley and Mahajan: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogenesis
Thermogenesis is the process of heat production in organisms. It occurs in all warm-blooded animals, and also in a few species of thermogenic plants such as the Eastern skunk cabbage, the Voodoo lily ('' Sauromatum venosum''), and the giant water lilies of the genus '' Victoria''. The lodgepole pine dwarf mistletoe, '' Arceuthobium americanum'', disperses its seeds explosively through thermogenesis. Types Depending on whether or not they are initiated through locomotion and intentional movement of the muscles, thermogenic processes can be classified as one of the following: * Obligatory Thermogenesis: Heat produced from energy expended for vital metabolic processes necessary to sustain an organism. * Exercise activity thermogenesis (EAT) * Non-exercise activity thermogenesis (NEAT): Energy expended for any spontaneous physical activity that is not a structured exercise routine or sports-like exercise. This can include but is not limited to walking, leisure activities, fid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post Micturition Convulsion Syndrome
In neurourology, post-micturition convulsion syndrome (PMCS), also known informally as pee shivers or piss shivers, is the experience of shivering during or after urination. The syndrome seems to be experienced more often by men than women. The term "post-micturition convulsion syndrome" was coined in 1994 in the online question-and-answer newspaper column '' The Straight Dope'', when a reader inquired about the phenomenon. Explanation There has yet to be any peer-reviewed research on the topic. The most plausible theory is that the shiver is a result of the autonomic nervous system getting its signals mixed up between its two main divisions: *The sympathetic nervous system (SNS), which controls bladder function, preventing urination. *The parasympathetic nervous system (PNS), which relaxes the urethral sphincter and contracts the bladder, causing urination. Part of the SNS response to a full bladder is the release of catecholamines (including epinephrine, norepinephri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fever
Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with Human body temperature, body temperature exceeding the normal range caused by an increase in the body's temperature Human body temperature#Fever, set point in the hypothalamus. There is no single agreed-upon upper limit for normal temperature: sources use values ranging between in humans. The increase in set point triggers increased muscle tone, muscle contractions and causes a feeling of cold or chills. This results in greater heat production and efforts to conserve heat. When the set point temperature returns to normal, a person feels hot, becomes Flushing (physiology), flushed, and may begin to Perspiration, sweat. Rarely a fever may trigger a febrile seizure, with this being more common in young children. Fevers do not typically go higher than . A fever can be caused by many medical conditions ranging from non-serious to life-threatening. This includes viral infection, viral, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrexia
Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with body temperature exceeding the normal range caused by an increase in the body's temperature set point in the hypothalamus. There is no single agreed-upon upper limit for normal temperature: sources use values ranging between in humans. The increase in set point triggers increased muscle contractions and causes a feeling of cold or chills. This results in greater heat production and efforts to conserve heat. When the set point temperature returns to normal, a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure, with this being more common in young children. Fevers do not typically go higher than . A fever can be caused by many medical conditions ranging from non-serious to life-threatening. This includes viral, bacterial, and parasitic infections—such as influenza, the common cold, meningitis, urinary tract infections, append ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychogenic Shivering
Frisson ( , ; French for "shiver"), also known as aesthetic chills or psychogenic shivers, is a psychophysiological response to rewarding stimuli (including music, films, stories, people, photos, and rituals) that often induces a pleasurable or otherwise positively-valenced affective state and transient paresthesia (skin tingling or chills), sometimes along with piloerection (goose bumps) and mydriasis (pupil dilation). The sensation can occur as a mildly to moderately pleasurable emotional response to music with skin tingling. The psychological component (i.e., the pleasurable feeling) and physiological components (i.e., paresthesia, piloerection, and pupil dilation) of the response are mediated by the reward system and sympathetic nervous system, respectively. The stimuli that produce this response are specific to each individual. Frisson is of short duration, lasting only a few seconds. Typical stimuli include loud passages of music and passages—such as appoggiaturas a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Adipose Tissue
Brown adipose tissue (BAT) or brown fat makes up the adipose organ together with white adipose tissue (or white fat). Brown adipose tissue is found in almost all mammals. Classification of brown fat refers to two distinct cell populations with similar functions. The first shares a common embryological origin with muscle cells, found in larger "classic" deposits. The second develops from white adipocytes that are stimulated by the sympathetic nervous system. These adipocytes are found interspersed in white adipose tissue and are also named 'beige' or 'brite' (for "brown in white"). Brown adipose tissue is especially abundant in newborns and in hibernation, hibernating mammals. It is also present and metabolically active in adult humans, but its prevalence decreases as humans age. Its primary function is thermoregulation. In addition to heat produced by shivering muscle, brown adipose tissue produces heat by non-shivering thermogenesis. The therapeutic targeting of brown fat for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Warm-blooded
Warm-blooded is a term referring to animal species whose bodies maintain a temperature higher than that of their environment. In particular, homeothermic species (including birds and mammals) maintain a stable body temperature by regulating metabolic processes. Other species have various degrees of thermoregulation. Because there are more than two categories of temperature control utilized by animals, the terms ''warm-blooded'' and '' cold-blooded'' have been deprecated in the scientific field. Terminology In general, warm-bloodedness refers to three separate categories of thermoregulation. * Endothermy is the ability of some creatures to control their body temperatures through internal means such as muscle shivering or increasing their metabolism. The opposite of endothermy is ectothermy. * Homeothermy maintains a stable internal body temperature regardless of external influence and temperatures. The stable internal temperature is often higher than the immediate environme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeostasis
In biology, homeostasis (British English, British also homoeostasis; ) is the state of steady internal physics, physical and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium, and calcium ions, as well as the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in optimal conditions, and equilibrium is maintained by many regulatory mechanisms; it is thought to be the central motivation for all organic action. All home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondria
A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term ''mitochondrion'', meaning a thread-like granule, was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase popularized by Philip Siekevitz in a 1957 ''Scientific American'' article of the same name. Some cells in some multicellular organisms lack mitochondria (for example, mature mammalian red blood cells). The multicellular animal '' Henneguya salminicola'' is known to have retained mitochondrion-related organelles despite a complete loss of their mitochondrial genome. A large number of unicellular organisms, such as microspo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chattering Teeth
Chattering teeth is a bodily function in animals that occurs primarily in response to cold; the jaw muscles begin to shiver leading teeth to crash together. It may also occur as a result of bruxism where emotional stress causes the jaw movements. Certain medications can lead to teeth chattering as a side effect, especially antipsychotics and selective serotonin reuptake inhibitor Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs primarily work by blo ...s. References Symptoms and signs Cold Teeth {{Symptom-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
