Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when temperature surrounding is very different. This process is one aspect of homeostasis: a dynamic state of stability between an animal's internal environment and its external environment (the study of such processes in zoology has been called ecophysiology or physiological ecology). If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as heat stroke occurs. The opposite condition, when body temperature decreases below normal levels, is known as hypothermia. Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... For other uses, see Temperature (disambiguation). ... Homeostasis (from Greek: ὅμος, homos, equal; and ιστημι, histemi, to stand lit. ... Zoology (from Greek: ζῴον, zoion, animal; and λόγος, logos, knowledge) is the biological discipline which involves the study of animals. ... Normal human body temperature is a concept that depends on the place in the body at which the measurement is made. ... Hyperthermia in its advanced state referred to as heat stroke or sunstroke, is an acute condition which occurs when the body produces or absorbs more heat than it can dissipate. ... Hypothermia is a condition in which an organisms temperature drops below that Required fOr normal metabolism and Bodily functionS. In warm-blooded animals, core [[body Temperature]] is maintained nEar a constant leVel through biologic [[homEostasis]]. But wheN the body iS exposed to cold Its internal mechanismS may be unable...

Whereas an organism that thermoregulates is one that keeps its core body temperature within certain limits, a thermoconformer changes its body temperature with changes to the temperature outside of its body. It was not until the introduction of thermometers that any exact data on the temperature of animals could be obtained. It was then found that local differences were present, since heat production and heat loss vary considerably in different parts of the body, although the circulation of the blood tends to bring about a mean temperature of the internal parts. Hence it is important to determine the temperature of those parts which most nearly approaches to that of the internal organs. Also for such results to be comparable they must be made in the same situation. The rectum gives most accurately the temperature of internal parts, or in some cases of sex or species, the vagina, uterus or bladder. A clinical mercury thermometer A thermometer is a device that measures temperature or temperature gradient, using a variety of different principles. ... In biology, an organ is a group of tissues which perform some function. ... The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... This article is about female reproductive anatomy. ... This article is about the urinary bladder. ...

Occasionally the temperature of the urine as it leaves the urethra may be of use. More usually the temperature is taken in the mouth, axilla, ear or groin. This article is about the urine of animals generally. ... In anatomy, the urethra (from Greek ουρήθρα - ourethra) is a tube which connects the urinary bladder to the outside of the body. ... For other uses, see Mouth (disambiguation). ... The armpit (or axilla) is the area on the human body directly under the area where the arm connects to the shoulder. ... For other uses, see Ear (disambiguation). ... The groin is the crease at the junction of the torso with the legs and the adjacent region that includes the external genitals. ...

Thermoregulation in humans

As in other mammals, thermoregulation is an important aspect of human homeostasis. Heat is mainly produced by the liver and muscle contractions. Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid. High temperatures pose serious stresses for the human body, placing it in great danger of injury or even death. In order to deal with these climatic conditions, humans have developed physiologic and cultural modes of adaptation.

The skin assists in homeostasis (keeping different aspects of the body constant e.g. temperature). It does this by reacting differently to hot and cold conditions so that the inner body temperature remains more or less constant. Vasodilation and sweating are the primary modes by which humans attempt to lose excess body heat. The effectiveness of these methods is influenced by the character of the climate and the degree to which the individual is acclimatized.

In hot conditions

1. Sweat glands under the skin secrete sweat (a fluid containing mostly water with some dissolved ions) which travels up the sweat duct, through the sweat pore and onto the surface of the skin. This causes heat loss by evaporation; however, a lot of essential water is lost.
2. The hairs on the skin lie flat, preventing heat from being trapped by the layer of still air between the hairs. This is caused by tiny muscles under the surface of the skin called erector pili muscles relaxing so that their attached hair follicles are not erect. These flat hairs increase the flow of air next to the skin increasing heat loss by convection. When environmental temperature is above core body temperature, sweating is the only physiological way for humans to lose heat.
3. Arterioles Vasodilation occurs, this is the process of relaxation of smooth muscle in arteriole walls allowing increased blood flow through the artery. This redirects blood into the superficial capillaries in the skin increasing heat loss by radiation and conduction.

Note: Most animals can't sweat efficiently. Cats and dogs only have sweat glands on the pads of their feet. Horses and humans are two of the few animals capable of sweating. Many animals pant rather than sweat, this is because the lungs have a large surface area and are highly vascularised. Air is inhaled, cooling the surface of the lungs and is then exhaled losing heat and some water vapour. SWEAT is an OLN/TSN show hosted by Julie Zwillich that aired in 2003-2004. ... An arteriole is a blood vessel that extends and branchs out from an artery and leads to capillaries. ...

In cold conditions

1. Sweat stops being produced.
2. The minute muscles under the surface of the skin called erector pili muscles (attached to an individual hair follicle) contract (piloerection), lifting the hair follicle upright. This makes our hairs stand on end which acts as an insulating layer, trapping heat. This is what also causes goose pimples since humans don't have very much hair and the contracted muscles can easily be seen.
3. Arterioles carrying blood to superficial capillaries under the surface of the skin can shrink (constrict) blood is rerouted away from the skin and towards the warmer core of the body. This prevents blood from losing heat to the surroundings and also prevents the core temperature dropping further. This process is called vasoconstriction. It is impossible to prevent all heat loss from the blood, only to reduce it. In extremely cold conditions excessive vasoconstriction leads to numbness and pale skin. Frostbite only occurs when water within the cells begins to freeze, this destroys the cell causing damage.
4. Muscles can also receive messages from the thermo-regulatory centre of the brain (the hypothalamus) to cause shivering. This increases heat production as respiration is an exothermic reaction in muscle cells. Shivering is more effective than exercise at producing heat because the animal remains still. This means that less heat is lost to the environment via convection. There are two types of shivering: low intensity and high intensity. During low intensity shivering animals shiver constantly at a low level for months during cold conditions. During high intensity shivering animals shiver violently for a relatively short time. Both processes consume energy although high intensity shivering uses glucose as a fuel source and low intensity tends to use fats. This is why animals store up food in the winter.

Note: Messages from the brain that reach effectors (e.g. muscles and glands) are done so by motor neurons. Neurons are specialized cells that pass messages around the body in the form of electrical impulses. Motor neurons are the ones that pass messages from the brain directly to the effector, in this case muscles. A collection of thousands of neurons is termed a nerve. Goose bumps (AE), also called goose pimples, goose flesh (BE), chicken skin (Hawaiian Pidgin), or cutis anserina, are the bumps on a persons skin at the base of body hairs, which involuntarily develop when a person is cold, afraid, or experiences other strong emotions. ... Goose bumps on a human Goose bumps (AE), also called goose pimples, goose flesh (BE), chill bumps, chicken skin (Hawaiian Pidgin), or the medical term cutis anserina, are the bumps on a persons skin at the base of body hairs which involuntarily develop when a person is cold or... An arteriole is a blood vessel that extends and branchs out from an artery and leads to capillaries. ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ...

The process explained above, in which the skin regulates body temperature is a part of thermoregulation. This is one aspect of homeostasis-the process by which the body regulates itself to keep internal conditions constant.

Temperature symptoms

• Hypothermia
• Hyperthermia
• Raynaud's phenomenon (Raynaud's disease)
• Induced hypothermia
• Cold hands (medical symptom)

Hypothermia is a condition in which an organisms temperature drops below that Required fOr normal metabolism and Bodily functionS. In warm-blooded animals, core [[body Temperature]] is maintained nEar a constant leVel through biologic [[homEostasis]]. But wheN the body iS exposed to cold Its internal mechanismS may be unable... Hyperthermia in its advanced state referred to as heat stroke or sunstroke, is an acute condition which occurs when the body produces or absorbs more heat than it can dissipate. ... Raynauds phenomenon (RAY-noz), in medicine, is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other extremities, named for French physician Maurice Raynaud (1834 - 1881). ... Raynauds disease (RAY-noz) is a condition that affects blood flow to the extremities which include the fingers, toes, nose and ears when exposed to temperature changes or stress. ... Hypothermia being induced by using water circulated through heat-conducting pads Induced hypothermia (also known as therapeutic hypothermia) is the intentional induction of hypothermia for medical purposes. ...

Thermoregulation in vertebrates

Human thermoregulation (simplified)

By numerous observations upon humans and other animals, John Hunter showed that the essential difference between the so-called warm-blooded and cold-blooded animals lies in observed constancy of the temperature of the former, and the observed variability of the temperature of the latter. Almost all birds and mammals have a high temperature almost constant and independent of that of the surrounding air. This is called homeothermy. Almost all other animals display a variation of body temperature, dependent on their surroundings. This is called poikilothermy. Image File history File links Download high-resolution version (1907x1078, 65 KB) Simplified information processing structure of human thermoregulation. ... Image File history File links Download high-resolution version (1907x1078, 65 KB) Simplified information processing structure of human thermoregulation. ... Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ... Several people are known by the name John Hunter: John Hunter (surgeon), (1728 - 1793), was a surgeon and anatomist. ... A warm-blooded (homeothermic) animal is one that can keep its core body temperature at a nearly constant level regardless of the temperature of the surrounding environment (that is, to maintain thermal homeostasis) . This can involve not only the ability to generate heat, but also the ability to cool down... This article needs to be cleaned up to conform to a higher standard of quality. ... A warm-blooded (homeothermic) animal is one that can keep its core body temperature at a nearly constant level regardless of the temperature of the surrounding environment (that is, to maintain thermal homeostasis) . This can involve not only the ability to generate heat, but also the ability to cool down... Cold-blooded organisms, more technically known as poikilothermic, are animals that have no internal metabolic mechanism for regulating their body temperatures. ...

Certain mammals are exceptions to this rule, being warm-blooded during the summer or daytime, but cold-blooded during the winter when they hibernate or at night during sleep. J. O. Wakelin Barratt has demonstrated that under certain pathological conditions, a warm-blooded (homeothermic) animal may become temporarily cold-blooded (poikilothermic). He has shown conclusively that this condition exists in rabbits suffering from rabies during the last period of their life, the rectal temperature being then within a few degrees of the room temperature and varying with it. He explains this condition by the assumption that the nervous mechanism of heat regulation has become paralysed. The respiration and heart-rate being also retarded during this period, the resemblance to the condition of hibernation is considerable. Again, Sutherland Simpson has shown that during deep anaesthesia a warm-blooded animal tends to take the same temperature as that of its environment. He demonstrated that when a monkey is kept deeply anaesthetized with ether and is placed in a cold chamber, its temperature gradually falls, and that when it has reached a sufficiently low point (about 25 °C in the monkey), the employment of an anaesthetic is no longer necessary, the animal then being insensible to pain and incapable of being roused by any form of stimulus; it is, in fact, narcotised by cold, and is in a state of what may be called "artificial hibernation." Once again this is explained by the fact that the heat-regulating mechanism has been interfered with. Similar results have been obtained from experiments on cats. It has also been concluded that in humans, it is possible for as much as 80% of body heat lose to escape through the head. This is due to the skin on the head being relatively thin along with the abundance of blood vessels present. It is also known that in temperature differences, that of the higher temperature will raise. This causes heat to raise to the head and escape through the skin. This article refers to the process of hibernation in biology. ... This article refers to the process of hibernation in biology. ...

Ectotherms

Main article: Ectotherm

Cold-blooded organisms, more technically known as poikilothermic, are animals that have no internal metabolic mechanism for regulating their body temperatures. ...

Ectothermic cooling

Seeking shade is one method of cooling. Here Sooty Tern chicks are using a Black-footed Albatross chick for shade.

• Vaporization:
  • Getting wet in a river, lake or sea.
• Convection:
  • Climbing to lower ground from trees, into valleys, burrows, etc.
  • Entering a cold water or air current.
  • Building a nest that allows natural or generated air/water flow for cooling.
• Conduction:
  • Lie on cold ground.
  • Staying wet in a river, lake or sea.
  • Covering in cool mud.
• Radiation:
  • Find shade.
  • Enter a burrow shaped for radiating heat (Black box effect).
  • Expand folds of skin.
  • Expose wing surfaces.

Image File history File linksMetadata Size of this preview: 800 × 533 pixels Full resolution (3456 × 2304 pixel, file size: 4. ... Image File history File linksMetadata Size of this preview: 800 × 533 pixels Full resolution (3456 × 2304 pixel, file size: 4. ... Binomial name (Linnaeus, 1766) Synonyms Sterna fuscata Linnaeus, 1766 The Sooty Tern, Onychoprion fuscata — formerly Sterna fuscata (Bridge , 2005) — is a seabird of the tern family Sternidae. ... Binomial name Phoebastria nigripes (Audubon, 1839) The Black_footed Albatross, Phoebastria nigripes, is a large seabird from the North Pacific. ... A burrow is a hole or tunnel dug into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. ...

Ectothermic heating (or minimizing heat loss)

• Convection:
  • Climb to higher ground up trees, ridges, rocks.
  • Entering a warm water or air current.
  • Building an insulated nest or burrow.
• Conduction:
  • Lie on hot rock.
• Radiation:
  • Lie in sun.
  • Fold skin to reduce exposure.
  • Conceal wing surfaces.

Thermographic image of a snake around an arm

To cope with low temperatures, an some fish have developed the ability to remain functional even when the water temperature is below freezing; some use natural antifreeze or antifreeze proteins to resist ice crystal formation in their tissues. Amphibians and reptiles cope with heat loss by evaporative cooling and behavioral adaptations. Image File history File links Wiki_stranglesnake. ... Image File history File links Wiki_stranglesnake. ... For other uses, see Fish (disambiguation). ... For other uses, see Antifreeze (disambiguation). ... Antifreeze proteins (AFPs) or ice structuring proteins (ISPs) refer to a class of polypeptides produced by certain vertebrates, plants, fungi and bacteria that permit their survival in subzero environments. ... For other uses, see Amphibian (disambiguation). ... Reptilia redirects here. ...

Endotherms

Main article: Endotherm

To regulate body temperature, an organism may need to prevent heat gains in arid environments. Evaporation of water, either across respiratory surfaces or across the skin in those animals possessing sweat glands, helps in cooling body temperature to within the organism's tolerance range. Animals with a body covered by fur have limited ability to sweat, relying heavily on panting to increase evaporation of water across the moist surfaces of the lungs and the tongue and mouth. Birds also avoid overheating by gular fluttering which is similar to panting in mammals since their thin skin has no sweat glands. Down feathers trap warm air acting as excellent insulators just as hair in mammals acts as a good insulator; mammalian skin is much thicker than that of birds and often has a continuous layer of insulating fat beneath the dermis — in marine mammals like whales this is referred to as blubber. Dense coats found in desert endotherms also aid in preventing heat gain. Another cold weather strategy is to temporarily decrease metabolic rate and body temperature regulated decrease in body temperature decreases the temperature difference between the animal and the air and therefore minimizes heat loss. Furthermore, having a lower metabolic rate is less energetically expensive. Many animals survive cold frosty nights through torpor, a short-term temporary drop in body temperature. Organisms when presented with the problem of regulating body temperature not only have behavioural, physiological and structural adaptations, but also a feedback system to trigger these adaptations to regulate temperature accordingly. The main features of this system are; Stimulus, Receptor, Modulator, Effector and then the feedback of the now adjusted temperature to the Stimulus. This cyclical process aids in homeostasis. A warm-blooded (homeothermic) animal is one that can keep its core body temperature at a nearly constant level regardless of the temperature of the surrounding environment (that is, to maintain thermal homeostasis) . This can involve not only the ability to generate heat, but also the ability to cool down... For other uses, see Bird (disambiguation). ... The down of birds is a layer of fine feathers found under the tougher exterior feathers. ... Torpor is a (usually short-term) state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. ...

Heat production in birds and mammals

In cold environments, birds and mammals employ the following adaptations and strategies to minimize heat loss:

1. using small smooth muscles (erector pili in mammals) which are attached to feather or hair shafts; this non-shivering thermogenesis distorts the surface of the skin as the feather/hair shaft is made more erect (called goose bumps or pimples)
2. increasing body size to more easily maintain core body temperature (warm-blooded animals in cold climates tend to be larger than similar species in warmer climates (see Bergmann's Rule))
3. having the ability to store energy as fat for metabolism
4. have shortened extremities
5. have countercurrent blood flow in extremities - this is where the warm arterial blood travelling to the limb passes the cooler venous blood from the limb and heat is exchanged warming the venous blood and cooling the arterial (e.g. Arctic Wolf^[1] or penguins^[2][3])

In warm environments, birds and mammals employ the following adaptations and strategies to maximize heat loss: Goose bumps on a human Goose bumps, also called goose pimples, goose flesh, chill bumps, chicken skin, or the medical term cutis anserina, are the bumps on a persons skin at the base of body hairs which involuntarily develop when a person is cold or experiences strong emotions such... The large size of a polar bear allows it to radiate less heat in a cold climate. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... Countercurrent exchange is a mechanism used to transfer some component of a fluid from one flowing current of fluid to another across a permeable barrier between them. ... Trinomial name Canis lupus arctos Pocock, 1935 Arctic Wolf ranges The Arctic Wolf (Canis lupus arctos), also called Polar Wolf or White Wolf, is a mammal of the Canidae family, and a subspecies of the Gray Wolf. ...

1. behavioural adaptations like living in burrows during the day and being nocturnal
2. evaporative cooling by perspiration and panting
3. storing fat reserves in one place (e.g. camel's hump) to avoid its insulating effect
4. elongated, often vascularized extremities to conduct body heat to the air

Thermoregulation in plants

Thermogenesis occurs in the flowers of many plants in the Araceae family as well as in cycad cones.^[4] In addition, some plants in the Alum family - such as the Eastern Skunk Cabbage, the Philodendron (Philodendron selloum), and the Sacred lotus (Nelumbo nucifera) are able to thermoregulate themselves,^[5] remaining on average 20°C (36°F) above air temperature while flowering. Heat is produced by breaking down the starch that was stored in their roots,^[6] which requires the consumption of oxygen at a rate approaching that of a flying hummingbird.^[7] Thermogenesis is the process of heat production in organisms. ... Genera See text. ... Families Cycadaceae cycas family Stangeriaceae stangeria family Zamiaceae zamia family Leaves and male cone of Cycas revoluta Cycads are an ancient group of seed plants characterized by a large crown of compound leaves and a stout trunk. ... A crystal of alum Alum, (IPA: ) a nonexistent compound that was imagined by Mary Daly, which serves no purpose than to supply highscool students with work. ... Binomial name Symplocarpus foetidus Salisb. ... {{Taxobox | color = lightgreen | name = Philodendrons | image = Philodendron01. ... Binomial name Nelumbo nucifera Gaertn. ... For other uses, see Hummingbird (disambiguation). ...

One possible explanation for plant thermoregulation is to provide protection against cold temperature. For example, the skunk cabbage is not frost-resistant, yet it begins to grow and flower when there is still snow on the ground.^[4] Another theory is that thermogenicity helps attract pollinators, which is borne out by observations that heat production is accompanied by the arrival of beetles or flies.^[8]

Behavioural temperature regulation

In addition to human beings, a number of other animals also maintain their body temperature with physiological and behavioral adjustments. For example, a desert lizard is an ectotherm and is therefore unable to control its temperature through metabolic regulation. However, by altering its location continuously, it is able to maintain a crude form of temperature control. In the morning, only its head will emerge from its burrow. Later, the entire body is exposed. The lizard basks in the sun, absorbing solar heat. When the temperature reaches higher levels, the lizard will hide under rocks or return to its burrow. When the sun goes down or the temperature falls, it emerges again. Cold-blooded organisms, more technically known as poikilothermic, are animals that have no internal metabolic mechanism for regulating their body temperatures. ...

Some animals living in cold environments maintain their body temperature by preventing heat loss. Their fur grows more densely to increase the amount of insulation. Some animals are regionally heterothermic and are able to allow their less insulated extremities to cool to temperatures much lower than their core temperature -- nearly to 0 °C. This minimizes heat loss through less insulated body parts, like the legs, feet (or hooves), and nose. Wikimedia Commons has media related to: Thermal insulation Thermal insulation on the Huygens probe Rockwool Insulation, 1600 dpi scan against the grain Rockwool Insulation, 1600 dpi scan with the grain The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and... Heterothermic (from Greek: hetero = other thermy = heat. ...

An ostrich can keep its body temperature very constant, even though it can be very hot during the day and cold at night.

Image File history File links Wiki_ostrich. ... Image File history File links Wiki_ostrich. ...

Hibernation, estivation, and daily torpor

To cope with limited food resources and low temperatures, some mammals hibernate in underground burrows. In order to remain in "stasis" for long periods, these animals must build up brown fat reserves and be capable of slowing all body functions. True hibernators (e.g. groundhogs) keep their body temperature down throughout their hibernation while the core temperature of false hibernators (e.g. bears) varies with them sometimes emerging from their dens for brief periods. Some bats are true hibernators which rely upon a rapid, non-shivering thermogenesis of their brown fat deposit to bring them out of hibernation. This article refers to the process of hibernation in biology. ... Brown adipose tissue (BAT) or brown fat is one of the two types of adipose tissue (the other being white adipose tissue) that is present in many newborn or hibernating mammals. ... Core temperature is the operating temperature of an organism, specifically in deep structures of the body such as the liver, in comparison to temperatures of peripheral tissues. ...

Estivation occurs in summer (like siestas) and allows some mammals to survive periods of high temperature and little water (e.g. turtles burrow in pond mud). Estivation or aestivation (from Latin aestas, summer) is a state of dormancy similar to hibernation. ... A painting of a young woman taking a siesta. ...

Daily torpor occurs in small endotherms like bats and humming birds which temporarily reduce their high metabolic rates to conserve energy.^[9] Torpor is a (usually short-term) state of decreased physiological activity in an animal, usually characterized by a reduced body temperature and rate of metabolism. ...

Variations in the temperature of human beings and some animals

Chart showing diurnal variation in body temperature, ranging from about 37.5 °C from 10 a.m. to 6 p.m., and falling to about 36.3 °C from 2 a.m. to 6 a.m.

Download high resolution version (1644x979, 35 KB)Chart showing diurnal variation in body temperature, ranging from about 37. ... Download high resolution version (1644x979, 35 KB)Chart showing diurnal variation in body temperature, ranging from about 37. ...

Normal human temperature

Main article: Normal human body temperature

Previously, average oral temperature for healthy adults had been considered 37.0 °C (98.6 °F), while normal ranges are 36.1 °C (97.0 °F) to 37.8 °C (100.0 °F). In Poland and Russia, the temperature had been measured axillary. 36.6 °C was considered "ideal" temperature, while normal ranges are 36 °C to 36.9 °C. Normal human body temperature is a concept that depends on the place in the body at which the measurement is made. ...

Recent studies suggest that the average temperature for healthy adults is 98.2 °F or 36.8 °C (same result in three different studies). Variations (one standard deviation) from three other studies are: In probability and statistics, the standard deviation of a probability distribution, random variable, or population or multiset of values is a measure of statistical dispersion of its values. ...

• 36.4 - 37.1 °C
• 36.3 - 37.1 °C for males, 36.5 - 37.3 °C for females
• 36.6 - 37.3 °C^[10]

Variations from thermometer placement

Temperature varies according to thermometer placement, with rectal temperature being 0.3-0.6 °C (0.5-1 °F) higher than oral temperature, while axillary temperature is 0.3-0.6 °C (0.5-1 °F) lower than oral temperature.^[11] The average difference between oral and axillary temperatures of Indian children aged 6-12 was found to be only 0.1 °C (standard deviation 0.2 °C),^[12] and the mean difference in Malta children aged 4-14 between oral and axillary temperature was 0.56 °C, while the mean difference between rectal and axillary temperature for children under 4 years old was 0.38 °C.^[13]

Variations associated with development

Of the lower warm-blooded animals, there are some that appear to be cold-blooded at birth. Kittens, rabbits and puppies, if removed from their surroundings shortly after birth, lose their body heat until their temperature has fallen to within a few degrees of that of the surrounding air. But such animals are at birth blind, helpless and in some cases naked. Animals who are born when in a condition of greater development can maintain their temperature fairly constant. In strong, healthy infants a day or two old the temperature rises slightly, but in that of weakly, ill-developed children it either remains stationary or falls. The cause of the variable temperature in infants and young immature animals is the imperfect development of the nervous regulating mechanism. Binomial name Felis catus Linnaeus, 1758 Synonyms Felis lybica invalid junior synonym The cat (or domestic cat, house cat) is a small carnivorous mammal. ... For other uses, see Rabbit (disambiguation). ... Trinomial name Canis lupus familiaris The dog (Canis lupus familiaris) is a domestic subspecies of the wolf, a mammal of the Canidae family of the order Carnivora. ...

The average temperature falls slightly from infancy to puberty and again from puberty to middle age, but after that stage is passed the temperature begins to rise again, and by about the eightieth year is as high as in infancy. “Baby” redirects here. ... Puberty refers to the process of physical changes by which a childs body becomes an adult body capable of reproduction. ... Middle age is the period of life beyond young adulthood but before the onset of old age. ... Paul Kruger in his old age. ...

Variations due to circadian rhythms

In humans, a diurnal variation has been observed dependent on the periods of rest and activity, lowest at 11 p.m. to 3 a.m. and peaking at 10 a.m. to 6 p.m. Monkeys also have a well-marked and regular diurnal variation of body temperature which follows periods of rest and activity, and is not dependent on the incidence of day and night; nocturnal monkeys reach their highest body temperature at night and lowest during the day. Sutherland Simpson and J.J. Galbraith observed that all nocturnal animals and birds - whose periods of rest and activity are naturally reversed through habit and not from outside interference - experience their highest temperature during the natural period of activity (night) and lowest during the period of rest (day). Those diurnal temperature can be reversed by reversing their daily routine.^[14] Approximate worldwide distribution of monkeys. ... A nocturnal animal is one that sleeps during the day and is active at night - the opposite of the human (diurnal) schedule. ...

The temperature curve of diurnal birds is essentially similar to that of man and other homoeothermal animals, except that the maximum occurs earlier in the afternoon and the minimum earlier in the morning. Also that the curves obtained from rabbits, guinea pigs and dogs were quite similar to those from man. These observations indicate that body temperature is partially regulated by circadian rhythms. A diurnal animal (dī-ŭrnəl) is an animal that is active during the daytime and sleeps during the night. ... For other uses, see Guinea pig (disambiguation). ... A circadian rhythm is an approximate daily periodicity, a roughly-24-hour cycle in the biochemical, physiological or behavioral processes of living beings, including plants, animals, fungi and cyanobacteria. ...

Variations due to women's menstrual cycles

During the follicular phase (which lasts from the first day of menstruation until the day of ovulation), the average basal body temperature in women ranges from 36.45 - 36.7 °C (97.6 - 98.6 °F). Within 24 hours of ovulation, women experience an elevation of 0.15 - 0.45 °C (0.2 - 0.9 °F) due to the increased metabolic rate caused by sharply elevated levels of progesterone. The basal body temperature ranges between 36.7 - 37.3°C (97.6 - 99.2°F) throughout the luteal phase, and drops down to pre-ovulatory levels within a few days of menstruation.^[15] Women can chart this phenomenon to determine whether and when they are ovulating, so as to aid conception or contraception. Menstrual cycle The follicular phase (or proliferative phase) is the phase of the estrous cycle, (or, in humans and great apes, the menstrual cycle) during which follicles in the ovary mature. ... See also Mensuration, a term sometimes used to describe Measurement, particularly in the context of forestry. ... Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... Basal body temperature is the body temperature measured immediately after awakening and before any physical activity has been undertaken. ... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... The luteal phase is the latter phase of the estrous cycle in animals. ...

Variations due to fever

Fever is a regulated elevation of the set point of core temperature in the hypothalamus, caused by circulating pyrogens produced by the immune system. To the subject, a rise in core temperature due to fever may result in feeling cold in an environment that people without fever do not. An analogue medical thermometer showing the temperature of 38. ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ...

Variations due to biofeedback

A group of monks known as the Tummo are known to practice biofeedback meditation techniques that allow them to raise their body temperatures substantially.^[16] Tumo (also spelled Tummo, or Tum-mo ) is a Tibetan term for a type of contemplative practice that causes an intense sensation of body heat to arise. ... Biofeedback mechanism. ... For other senses of this word, see Meditation (disambiguation). ...

Variations due to other factors

The factual accuracy of this section is disputed. Please see the relevant discussion on the talk page.(March 2008)

In Simpson's & Galbraith's work, the mean temperature of the female was higher than that of the male in all the species examined whose sex had been determined.

Meals sometimes cause a slight elevation, sometimes a slight depression—alcohol seems always to produce a fall. Exercise and variations of external temperature within ordinary limits cause very slight change, as there are many compensating influences at work, which are discussed later. The core temperature of those living in the tropics is within a similar range to those dwelling in the Arctic regions. For the ships, see USS Arctic, SS Arctic, MV Arctic The red line indicates the 10°C isotherm in July, sometimes used to define the Arctic region border Artificially coloured topographical map of the Arctic region The Arctic is the region around the Earths North Pole, opposite the Antarctic...

Low body temperature increases lifespan

It was long theorised that low body temperature may prolong life. On November 2006, a team of scientists from the Scripps Research Institute reported that transgenic mice which had body temperature 0.3-0.5 C lower than normal mice (due to overexpressing the uncoupling protein 2 in hypocretin neurons (Hcrt-UCP2), which elevated hypothalamic temperature, thus forcing the hypothalamus to lower body temperature) indeed lived longer than normal mice. The lifespan was 12% longer for males and 20% longer for females. Mice were allowed to eat as much as they wanted.^[17][18][19] The effects of body temperature on longevity have not been studied in humans. The Scripps Research Institute, in La Jolla, California is home to notable chemists such as K. Barry Sharpless and P. G. Schultz, as well as neurobiologist Gerald Edelman, and Nobel Laureate Kurt Wurtrich. ... The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). ...

Limits compatible with life

There are limits both of heat and cold that a warm-blooded animal can bear, and other far wider limits that a cold-blooded animal may endure and yet live. The effect of too extreme a cold is to lessen metabolism, and hence to lessen the production of heat. Both catabolic and anabolic changes share in the depression, and though less energy is used up, still less energy is generated. This diminished metabolism tells first on the central nervous system, especially the brain and those parts concerned in consciousness. Both heart rate and respiration rate become diminished, drowsiness supervenes, becoming steadily deeper until it passes into the sleep of death. Occasionally, however, convulsions may set in towards the end, and a death somewhat similar to that of asphyxia takes place. Anabolism is the metabolic process that builds larger molecules from smaller ones. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... A diagram showing the CNS: 1. ... For other uses, see Brain (disambiguation). ... Heart rate is the frequency of the cardiac cycle. ... The respiration rate is a parameter which is used in ecological and agronomical modelling. ... This article is about the medical condition. ... Suffocation redirects here, for the band, see Suffocation (band). ...

In some experiments on cats performed by Sutherland Simpson and Percy T. Herring, they found them unable to survive when the rectal temperature was reduced below 16°C. At this low temperature respiration became increasingly feeble, the heart-impulse usually continued after respiration had ceased, the beats becoming very irregular, apparently ceasing, then beginning again. Death appeared to be mainly due to asphyxia, and the only certain sign that it had taken place was the loss of knee jerks.

On the other hand, too high a temperature hurries on the metabolism of the various tissues at such a rate that their capital is soon exhausted. Blood that is too warm produces dyspnea and soon exhausts the metabolic capital of the respiratory centre. Heart rate is increased, the beats then become arrhythmic and finally cease. The central nervous system is also profoundly affected, consciousness may be lost, and the patient falls into a comatose condition, or delirium and convulsions may set in. All these changes can be watched in any patient suffering from an acute fever. The lower limit of temperature that man can endure depends on many things, but no one can survive a temperature of 45°C (113°F) or above for very long. Mammalian muscle becomes rigid with heat rigor at about 50°C, and obviously should this temperature be reached the sudden rigidity of the whole body would render life impossible. Dyspnea (R06. ... In medicine, a coma (from the Greek koma, meaning deep sleep) is a profound state of unconsciousness, which may result from a variety of conditions including intoxication (drug, alcohol or toxins), metabolic abnormalities (hypoglycemia, hyperglycemia, ketoacidosis, etc. ... This article is about the mental state and medical condition. ... An analogue medical thermometer showing the temperature of 38. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria For the folk-rock band see The Mammals. ...

H.M. Vernon has done work on the death temperature and paralysis temperature (temperature of heat rigor) of various animals. He found that animals of the same class of the animal kingdom showed very similar temperature values, those from the Amphibia examined being 38.5°C, Fish 39°C, Reptilia 45°C, and various Molluscs 46°C. Also in the case of Pelagic animals he showed a relation between death temperature and the quantity of solid constituents of the body. In higher animals, however, his experiments tend to show that there is greater variation in both the chemical and physical characters of the protoplasm, and hence greater variation in the extreme temperature compatible with life. For other uses, see Amphibian (disambiguation). ... For other uses, see Fish (disambiguation). ... Orders  Crocodilia - Crocodilians scary crocodiles. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... The pelagic zone is the part of the open sea or ocean comprising the water column, i. ... In biology, protoplasm is the living substance inside the cell. ...

Human temperature variation effects

Hot

• 37°C (98.6°F) - Normal body temperature (which varies between about 36.12-37.5°C (96.8-99.5°F)
• 38°C (100.4°F) - Sweating, feeling very uncomfortable, slightly hungry.
• 39°C (102.2°F) - Severe sweating, flushed and very red. Fast heart rate and breathlessness. There may be exhaustion accompanying this. Children and people with epilepsy may be very likely to get convulsions at this point.
• 40°C (104°F) - Fainting, dehydration, weakness, vomiting, headache and dizziness may occur as well as profuse sweating.
• 41°C (105.8°F) - (Medical emergency) - Fainting, vomiting, severe headache, dizziness, confusion, hallucinations, delirium and drowsiness can occur. There may also be palpitations and breathlessness.
• 42°C (107.6°F) - Subject may turn pale or remain flushed and red. They may become comatose, be in severe delirium, vomiting, and convulsions can occur. Blood pressure may be high or low and heart rate will be very fast.
• 43°C (109.4°F) - Normally death, or there may be serious brain damage, continuous convulsions and shock. Cardio-respiratory collapse will likely occur.
• 44°C (111.2°F) or more - Almost certainly death will occur; however, patients have been known to survive up to 46.5°C (115.7°F).^[20]

{{Otheruses4|the medical term|the Australian television series|Medical Emergenc an immediate threat to a persons life or long term health. ...

Cold

• 37°C (98.6°F) - Normal body temperature (which varies between about 36-37.5°C (96.8-99.5°F)
• 36°C (96.8°F) - Mild to moderate shivering (it drops this low during sleep). May be a normal body temperature.
• 35°C (95.0°F) - (Hypothermia) is less than 35°C (95.0°F) - Intense shivering, numbness and bluish/grayness of the skin. There is the possibility of heart irritability.
• 34°C (93.2°F) - Severe shivering, loss of movement of fingers, blueness and confusion. Some behavioural changes may take place.
• 33°C (91.4°F) - Moderate to severe confusion, sleepiness, depressed reflexes, progressive loss of shivering, slow heart beat, shallow breathing. Shivering may stop. Subject may be unresponsive to certain stimuli.
• 32°C (89.6°F) - (Medical emergency) Hallucinations, delirium, complete confusion, extreme sleepiness that is progressively becoming comatose. Shivering is absent (subject may even think they are hot). Reflex may be absent or very slight.
• 31°C (87.8°F) - Comatose, very rarely conscious. No or slight reflexes. Very shallow breathing and slow heart rate. Possibility of serious heart rhythm problems.
• 28°C (82.4°F) - Severe heart rhythm disturbances are likely and breathing may stop at any time. Patient may appear to be dead.
• 24-26°C (75.2-78.8°F) or less - Death usually occurs due to irregular heart beat or respiratory arrest; however, some patients have been known to survive with body temperatures as low as 14.2°C (57.5°F).^[20]

Hypothermia is a condition in which an organisms temperature drops below that Required fOr normal metabolism and Bodily functionS. In warm-blooded animals, core [[body Temperature]] is maintained nEar a constant leVel through biologic [[homEostasis]]. But wheN the body iS exposed to cold Its internal mechanismS may be unable... {{Otheruses4|the medical term|the Australian television series|Medical Emergenc an immediate threat to a persons life or long term health. ...

Notes