The regulation of the internal temperature of the body is necessary, it is considered to be one of the most important examples of homeostasis in the body. Mammals, also called endotherms usually have a fairly constant body temperature that the body operates at. Endothermic organisms (including Humans) maintain their body temperatures at about 35ᵒC to 40ᵒC, further classifying them as warm blooded animals. Apart from the internal homeostasis that the body goes through in order to keep the body temperature constant, mammals use behavioral mechanisms, for example lying in the sun when it gets cold. When the behavioral mechanisms are coupled with the internal mechanism, there is an increase in effectiveness to ensure that the temperature of the blood going to different parts of the body is kept at a constant temperature. The brain and the heart are highly critical for the survival of humans, if in any instant, the temperature of the blood is changed from what would be classified a normal, there could be serious implications like, heart or brain failure, which would lead to death.
The thermoregulatory center in the hypothalamus controls the temperature at which the human body operates. There are two sets of thermoreceptors involved in the controlling of the body temperature. The receptor in the hypothalamus and the receptor in the skin. The receptor in the hypothalamus is used to monitor the temperature of the blood that passes through the brain; this is considered as the core temperature of the body. The receptor in the skin is used as a monitor of the external environment. These set of information is required in order for the body to be able to make the appropriate adjustments to keep the temperature constant. This therefore allows the body to know whether to cool down, or heat up. With the use of the thermoregulatory center several impulses are sent to different parts of the body, these are called effectors, this further allows the body adjust the temperature accordingly.
The effector, for example, sweat glands, skeletal muscles, behavior or even the smooth muscles in arterioles in the skin, all have different responses that they how to different temperature changes. The smooth muscles in low temperatures causes vasoconstriction, this is where lesser heat is carried from the core surface of the human body which further maintains the core temperature. In high temperatures the response from the smooth muscles is to carry more heat to the core surface of the body, this is called vasodilation. This heat is furthermore lost through convection and radiation. Sweat glands produce no sweat as a response to low temperatures, while in high temperatures, the glands create sweat to the skin surface allowing the evaporation of sweat and keeping the internal environment cool. The skeletal muscles contract and relax in low temperatures which generate heat from the friction caused by the muscles; heat is also created from metabolic reactions like respiration. In the presence of cooler weathers the response from the muscle is not to shiver. Behavioral Reponses include putting on more clothes or curling up in the cooler temperatures and finding shade in warmer temperatures. All these effectors are used by the body to maintain the appropriate temperature for the body to operate efficiently.
Effectors like the erector pili muscles and the thyroid glands also play big part in the maintenance of body temperature in the human body. The erector pili muscles contract which raises the skin hairs which traps a layer of warm air insulating next to the skin. In higher temperatures however, the muscles are relaxed allowing are to circulate over the skin, which allows evaporation and conduction. The thyroid and adrenal glands are able to secret adrenaline and thyroxine thus creating and increasing the metabolic rate of the different tissues, mainly in the liver. This further generates heat in lower temperatures. In higher temperature these glands do the exact opposite of this action and stop secreting altogether.
37.5ᵒC± 0.5ᵒC is the set point that the thermoregulatory center of the human body usually maintains. As explained earlier the is this temperature is not maintained, and the set point is altered there could be serious implications. However there are few exceptions to this that would require for the body to change the maintained temperature.
Pyrogens are chemical that are released by white blood cells which raise the set point of the thermoregulation center which furthermore cases the body temperature to increase by about 2 to 3 ᵒC. This allows the killing of bacteria, inhibits viruses, these work to prevent the body from sicknesses, especially during a fever, hence why people shiver even though they feel hot.
The body goes through different types of responses to changes in external temperatures. These are called voluntary and involuntary responses. Voluntary responses is the responses that a human takes to keep their body at a constant temperature, for example putting on more clothes when it is cold or going for a swim when it is hot. In the instant that the voluntary responses taken by the person is not enough, the thermoregulatory center is stimulated. This is considered as an involuntary response, these responses are part of the autonomic nervous system in the human body. Therefore when the body becomes too hot, the heat loss center is simulated in the hypothalamus, and when the body gets too cold, the hat conservation center in the hypothalamus is stimulated. Thermogenesis is the process by which heat is produced in the body this response is used in low temperature changes to generate heat and keep the body warm.
The human body goes through extreeme cases where thermoregulation does not work as effectiveluy as it should. When the external temoperaturre is hot, the body goes through several stages in order to maintain stability, homeostasis occurs in the form of sweating, being slightly hungry, and with worst case scenarios of fainting, vomitting cadio disfunction and death. Therefore when there are high temperature changes in the body temperature there is always cause for minimal to severe difunction in the body which can in turn lead to the death of the individual.
When the internal temperatures are cooler than the normal set point, individuals are faced with severe simptoms like shivering, which can in turn lead to numbness, unconsiousness, dilerium, and breathing problems to name a few. This furhtere implements the reason as to why hpomeostasis in the body is highly critical in the body. The worst case scenario could always be death in both the extreme cases, be it severe cold or sever heat.