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30

In the periphery (e.g. on our fingertips), our body senses external temperature through nerve terminals, expressing certain TRP channels. These are ion channels that are sensitive to temperature (note that TRP channels can be sensitive to several things, such as pH, light, and stretch) and allow entrance of cations in the cell when the temperature is higher ...


21

Hypothermia (when the body is too cold) is said to occur when the core body temperature of an individual has dropped below 35° celsius. Normal core body temperature is 37°C. (1) Hypothermia is then further subdivided into levels of seriousness (2) (although all can be damaging to health if left for an extended period of time) Mild 35–32 °C: shivering, ...


14

To complement on nico's answer (I don't have enough rep to comment), TRP channels seems to be also sensitive to increment or decrement of temperature as reported recently in a paper by Gallio et al1. Probably that channels have incomplete adaptative behavior that make them sensitive both to increment and absolute temperature values. [1] Gallio M, Ofstad ...


7

As Rory explained, internal body temperature needs to be highly regulated. Sweating is the main built in mechanism for removing excess heat from the human body. According to my biology book, in (100%) humid conditions humans cannot survive in heats of above around 45C, but in a dry environment can survive in heats of over 100C just through sweating.


6

Short answer Humans sense temperature differences. Background (Including edits based upon comments) Because the question is "Do humans perceive temperature or heat-flux?", I will answer the answer from a psychophysical perspective, i.e., by dealing with sensory awareness. Just as with many other sensory systems, temperature sensors in the human body ...


5

Factors that can lower body temperature: low environment temperature low metabolic rate hypothyroidism I couldn't find any relevant study addressing the Japanese people situation, but: There is significant variation in metabolic rate in humans, independent of differences in body size, body composition, age, and gender. Although it has been generally ...


5

This is the modified answer in response to the discussion: Facts: There are warmth and cold receptors in the body at two places: The Peripheral receptors and the Central Receptors The peripheral receptors are present in skin and the central receptors in the body core at multiple sites the notable site being the hypothalamus The Temperature receptors have ...


4

A very basic model of virus inactivation is exponential decay. You can describe exponential decay with the $N(t) = N_0e^{-\lambda t}$ equation, of if you want to use half-time, then with the $N(t) = N_02^{-t/t_{1/2}}$, where $N$ is the value which reduces by time, $t$ is the time, $\lambda$ is the exponential decay constant and $t_{1/2}$ is the half-life ...


4

This due to a phenomenon called "cold shock". This induces a number of physiological changes in the fishs metabolism and also in its behaviour and can lead to death. The first paper cites some reasons in table 1: Brain and central nervous system response: Changes in neuronal activity Catecholamine and corticosteroid response: Release of hormones due to ...


4

Flux is defined as amount of heat transferred per unit area per unit time. Our body does not perceive heat flux. It perceives temperature and tries to adjust heat exchange mechanisms until thermal homeostasis is achieved (in all warm blooded animals). This is a feedback controlled process. If it were to measure heat flux then the body cannot sense if it ...


3

The fingers and toes (for example) ARE at lower temperatures than the interior of the torso. It's why it's so easy to get frostbite on the extremities. As for temperature regulation of the testes, you have to also consider that humans evolved without clothes...i.e. The testes just "hang out" and get lots of airflow, as opposed to modern times, when they are ...


3

I've found a good resource for this--an open-access review by Nakamura, "Central Circuitries for Body Temperature Regulation and Fever." In it, the author provides a nice summary figure of the circuitry involved in temperature regulation (see below). As I suspected, the hypothalmus is pretty central to temperature regulation. I had forgotten about the ...


3

I am assuming that you are referring to a baseline human cooled to a core body temperature of 30C from birth. I am also assuming that you are ignoring the fact that the environmental temperature (and thus the temperature of the extremities) has to be much lower than 30C to cause a core temperature of 30C. Thus, I am ignoring hypothermia-based gangrene, ...


3

Gains heat; humans are not particularly well-adapted to make use of heat as an energy source. In a simple matter, if something you eat is hot when it goes in then the average temperature of the body has increased. More relevantly (and to get this more on-topic for biology), eating anything will generally increase your body temperature, as in order to ...


3

As far as I know, the main challenges the plants have to face in cold environment are metabolism reduction and membrane fluidity. If the temperature is even lower, they may face freezing. Increasing the metabolism is quite hard, because plants usually are unable to increase their temperature by its own. Plant may produce more pigments in order to absorb ...


3

This temperature range would be a compromise between a very low temperature needed to limit natural decay or decay triggered by micro-organisms (the lower the temperature, the lesser the decay) and the formation of destructive ice crystals. Only pure water freezes at 0°C (32°F) under atmospheric pressure. But the content of apple cells and cell walls is a ...


2

The discrepancy can be partly explained by where the temperature was measured from since the human body temperature ranges from 36.5 and 37.5 °C. For example it is 36.8 ± 0.4 °C when measured under the tongue (http://en.wikipedia.org/wiki/Human_body_temperature). Additionally The body temperature of a healthy person varies during the day by about 0.5 °C (0.9 ...


2

I do not have a source for the following as it was taught to me in neuroanatomy classes, the explanation given for brain freeze is that it is referred pain through the trigeminal nerve. The meninges (the tissue lining the central nervous system) is innervated by the trigeminal nerve in the head. Therefore the pain feels as though it is like a headache from ...


2

Yes, we can survive temperatures above 100 F (38 C) but surviving such temperatures requires continuous fluid intake. Since sweat evaporates quickly in an arid (dry) environment we tend to be unaware of how much water we're losing. This leads to heat exhaustion, then heat stroke, then death. Survival time depends on how well hydrated you are and whether ...


2

It's simply not possible for humans to live with an absolute body temperature below 20 C for the simple biophysical reason that it would prevent flux of protein through the Golgi and therefore biosynthetic and secretory pathways, as well as endocytosis. The lipid membranes become too "stiff" to correctly function. My own sense is that the nominal 37 C body ...


2

Endotherms also called warm blooded animals have the ability to regulate their body temperature by themselves. If the endotherms are in a cold place their body increases the metabolism and generates more heat. This will compensate for the cold outside. In a hot region the body metabolism is tuned down (this is not as efficient as the adaptation to cold ...


1

Enzymes usualy have a relative narrow temperature optimum, for those of our body this is usually around 37°C. It is around 37,2°C in the morning and goes slightly up to 37,7°C in the evening (see reference 1 for details). The temparature optimum for most enzymes looks somewhat like displayed in the figure (from here, interesting to read): Enzymes are ...


1

Disclaimer: the answer is very broad and covers both the situations I am confident about, as well as those I understand only superficially. The outcome depends on particular temperatures. Example - cold shock response: "Cold shock response is the physiological response of organisms to sudden cold, especially cold water. In humans, cold shock response is ...


1

In a cold climate, do people often blow out the air from their lungs a lot when living in the cold condition to keep their lungs warm? No, and it wouldn't make any sense: breathing more means inhaling more cold air that needs to be warmed up, so the result is a heat loss. The more so, as cold air (< 0°C) has a low water vapor pressure, while the lung ...


1

Heat loss hypothesis: I would rather think that blowing while speaking means that one has to inspire often and therefore he would lose much heat by convection. According this hypothesis, I would rather expect to see southern people blowing lots while speaking. Metabolism hypothesis: We might say that at low temperature the metabolism increases and ...


1

In response to cold your body causes blood supply to the skin to drop in the whole body. This is to conserve heat, but results in us feeling really cold. Exercising reverses this, resulting in an increased blood supply to the skin in order to remove excess heat and in this case we feel hot. As mentioned, the head receives a large blood supply, and ...


1

Things other than the temperature that could affect whether or not the coat is necessary: Is it raining? a wet dog will get cold quicker. How long/thick is the fur? thin coats of fur will be less efficient at keeping the dog warm than thick. Is it windy? Wind blows warm air out of the fur. How big is the dog? Size & body fat will affect the rate of heat ...


1

Some 200 years ago Dr.Charles Blagden, then secretary of Royal Society of London, went into a room that had been heated to a temperature of 126 degree Celsius ( 260 Fahrenheit) , taking with him a few friends , a small dog in a basket and a steak.The entire group remained there for 45 minutes. Dr.Blegden and his friends emerged unaffected. This ...



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