Which part of the brain controls temperature?

In this post we are going to answer the question  ‘’Which part of the brain controls temperature?’’ We will explain how the brain controls temperature, which is the region in charge, and we will give you all the details of the body’s thermoregulation processes.

Which part of the brain controls temperature?

The hypothalamus controls temperature. The hypothalamus has a dual system of temperature regulation. Thus, the anterior or rostral portion, composed of parasympathetic centers, is responsible for dissipating heat, while in the posterior portion, with sympathetic centers, it preserves and maintains body temperature.

The perception n of temperature It is relative, since we do not have receptors to perceive the temperature in an absolute way. We are only capable of perceiving sudden changes in temperature – for example, when moving our hand from a very cold water pot to a very hot one.

There are two types of receptors, some for cold and others for heat, heterogeneously distributed throughout the skin. Receptors for cold are closer to the epidermis, while receptors for heat are deeper. They are the same receptors; they only differ on the level of situation.

The transduction in these receptors is produced by the deformation of the membrane or the cone of the receptor as a result of the dilation or contraction of the skin. This produces the opening of the membrane and the sodium channels.

If the receptors are densely packed together, the sensation of heat will be more intense. The nuclei associated with our having difficulty perceiving cold and heat from the thalamus are intralaminar and to a lesser extent ventricular.

It is therefore extremely interesting to observe that the perception of pain is due, among other things, to small receptors in the skin and an excellent participation of the thalamus, the same happening with temperature.

All these functions seem to have been developed in pursuit of our survival, and these tools that we have are nothing more than an inheritance of what our ancestors once needed perhaps more than we do.

Thermoregulation

The temperature with which the blood reaches the hypothalamus will be the main determinant of the body’s response to climatic changes.

The hypothalamus has a dual system of temperature regulation. Thus, the anterior or rostral portion, composed of parasympathetic centers, is responsible for dissipating heat, while in the posterior portion, with sympathetic centers, it preserves and maintains body temperature.

When damage occurs in the posterior region in experimental animals, the response obtained is: prolonged hypothermia and inability to react to cold.

It also appears that the relative poikilothermia is the result of lesions in the posterior portion of the hypothalamus. Lesions located in the anterior or rostral region incapacitate the experimental animal to lose heat.

As we have already mentioned, the main determinant of the body’s response to climatic changes is the temperature with which the blood reaches the aforementioned regions of the hypothalamus.

When the neurons of the anterior or rostral hypothalamic center (sensitive to heat) are excited, a series of mechanisms are set in motion aimed at producing thermolysis, inhibiting the posterior hypothalamic center (conservative of temperature)

This causes an inoperation of all the thermogenic mechanisms, decreasing metabolism, muscle tone and progressively the production of thyroid hormone. Inhibition of the hypothalamic sympathetic centers leads to such vasodilation that the rate of heat transfer to the skin can be increased up to eight times.

All this leads to a decrease in temperature.

Stimulation of the anterior center per se lowers the temperature by activating the production of sweat and panting.

The sweat glands are under the control of the sympathetic nervous system, and influenced by cholinergic stimuli.

It is the cells of the posterior region (conserving heat) that predetermine the temperature of 37º.

The maintenance of the temperature and the reactions necessary to preserve it is carried out through impulses that arrive from the periphery (thermal receptors) and the temperature with which the blood reaches the hypothalamus, these impulses being conducted towards the posterior hypothalamic region.

The anterior zone would respond to these stimuli with the start-up of mechanisms that would lead to a loss of heat (sweating and panting).

The main pathway of the impulses that involve both mechanisms (heat production and loss) reaches the lateral hypothalamus, from there to the middle portion of the brain, pontine integument, reticular formation, medulla and from the sympathetic fibers to the cutaneous vessels, sweat glands and muscle motor fibers.

The hormonal response to changes in temperature is mediated by the hypothalamic-pituitary system. In hypothermic situations, there would be a release of TSH, ACTH, and consequently of thyroid hormones and corticosteroids. Aldosterone release in hyperthermia would be independent of ACTH production

Other neurotransmitters involved in thermoregulation:

Neuropeptides can also play an important role as neurotransmitters in thermoregulation. In experimental animals, a number of neuropeptides have been shown to be involved in controlling body temperature: neurotensin produces hypothermia when injected into the brain;

TRH is hypothermic in rabbits and rats, but the response varies if the injection is intraventricular; naloxone does not appear to have a significant effect on body temperature; somatostatin, which does not alter basal temperature, potentiates barbiturate-induced hypothermia, and inhibits the hypothermic effects of dopamine, apomorphine, and beta-endorphin.

All these peptides have shown effects on thermoregulation; however, its role in maintaining body temperature and diurnal variations in fever is awaiting clarification1.

Higher, homeothermic animals tend to keep their body temperature constant, this constant is not an exact figure, there is a circadian rhythm with a temperature peak between 18 and 22 hours of the day, being minimum between 2 and 4 in the At dawn.

There are also differences between different points of the body and in some physiological states, it is known by all that Ogino studied the physiological changes due to hormonal alterations in women, relating them to temperature.

Homeothermic animals are capable of adapting to the different temperatures that exist throughout the year, and in the different areas of our planet, which they do through the acclimatization process:

Acclimatization

It is the mechanism by which the body is able to adapt to different temperatures through repeated exposures. These exposures for 4-7 days to heat or exercise, cause modifications in the nervous, sensitive, hormonal and cardiovascular mechanisms, which allow a better tolerance to heat.

Heat acclimatization begins with the first exposure, progressing rapidly and being well advanced on the third or fourth day.

During the first exposures it is frequent that a great congestion appears in the head and face; rectal temperature and heart rate are elevated, sweat loss is low, and there is general discomfort and pain. In the following days the discomfort decreases, the rectal temperature and the heart rate fall, increasing sweating.

The respiratory system is relatively protected, since the temperature of the hot air inhaled drops rapidly in the upper airways (from 100º at the entrance of the nose to 40º at the rhinopharynx)

Aldosterone, a hormone highly involved in the acclimatization mechanism, exerts a similar function on the sweat glands as it does on the renal tubules, increasing the active absorption of Na. The Na that is absorbed is accompanied by a chloride ion.

The importance of this effect of aldosterone is to minimize the loss of NaCl through sweat, when the concentration of this salt is low in the blood.

The extreme loss of sweat, which occurs in continuously hot environments, can deplete the electrolytes of the extracellular fluid, being able to lose up to 20 grams of Na / day. Thanks to the action of aldosterone, after a period of acclimatization the loss is reduced to only 3-5 gr / day.

Man’s acclimatization to heat is achieved more perfectly if light work is carried out, which will progressively increase.

Sweating in the acclimatized person appears earlier than in the non-acclimatized person.

After acclimatization, there is less subjective discomfort from heat exposure. The increase in heart rate is lower, the breaths are moderate, there is greater cardiovascular stability, the production of sweat begins after a shorter exposure to heat and the concentration of Na in sweat decreases (which will be 5 mEq / l) and in urine.

Complete acclimatization occurs between 4-7 days and is maintained for weeks even if exposure to heat ceases.

Importance of body homeostasis

We understand body homeostasis as the existing tendency in the body to actively and constantly seek a state of balance, in such a way that the cells of our body can survive by maintaining a stable internal composition.

Maintaining this balance is essential, since the activation or maintenance of different bodily processes requires energy, which in turn requires elements to be used as fuel. Not having them will cause a series of tissue damage that can lead to death. 

The same happens if we are not able to activate or stop some of the aforementioned bodily processes, necessary for our survival.

It is important to bear in mind that homeostasis acts based on the existence of changes that can occur both within the body and come from the outside, also using mechanisms of action that link both environments (for example, hunger makes us eat).

In this sense, it must be taken into account that living beings can withstand certain levels of variation and imbalance and that the mechanisms that allow homeostasis can be damaged or altered throughout the life cycle, being important to take this into account in order to introduce factors external factors that correct possible deficits.

Another body mechanism that is continuously regulated is the internal body temperature. The correct functioning of our tissues and organs can be affected by excessive cold or heat, to the point of being able to lead us to death from hypothermia or hyperthermia.

Fortunately, our body is able to maintain temperature through a homeostatic process in which if there is excess internal temperature, the body reacts with a decrease in physical activity, discomfort and sweating (whose objective is to reduce the temperature).

Also with an increase in the temperature, the generation of tremors, the consumption of calories, the withdrawal of blood from secondary areas to direct it to vital areas and the search for heat in the case of lack of sufficient temperature.

FAQS: Which part of the brain controls temperature?

What part of the brain detects temperature?

The hypothalamus regulates the sleep and wake cycles, for this it is guided by external stimuli, such as light and temperature, which indicate to the brain when to induce sleep.

What are the symptoms of a malfunctioning hypothalamus?

The most common symptoms are:

Increased appetite and rapid weight gain.

Excessive thirst and frequent urination (diabetes insipidus)

Low body temperature

Slow heart rate

What happens if the hypothalamus is damaged?

Increased appetite and rapid weight gain. Excessive thirst and frequent urination (diabetes insipidus) Low body temperature. Slow heart rate

Which part of the hypothalamus controls temperature?

The hypothalamus has a dual system of temperature regulation. Thus, the anterior or rostral portion, composed of parasympathetic centers, is responsible for dissipating heat, while in the posterior portion, with sympathetic centers, it preserves and maintains body temperature.

What hormone controls body temp?

For this, the thyroid gland secretes thyroxine (T4), which is transformed into T3, which is the hormone in charge of regulating body temperature; In addition, it stimulates the growth of tissues and is essential for the development of the nervous system.

In this post we answered the question  ‘’Which part of the brain controls temperature?’’ We explained how the brain controls temperature, which is the region in charge, and we gave you all the details of the body’s thermoregulation processes.

If you have any questions or comments please let us know!

References

Zhu, M., Ackerman, J. J., Sukstanskii, A. L., & Yablonskiy, D. A. (2006). How the body controls brain temperature: the temperature shielding effect of cerebral blood flow. Journal of Applied Physiology, 101(5), 1481-1488.

Verbalis, J. G. (2003). Disorders of body water homeostasis. Best practice & research clinical endocrinology & metabolism, 17(4), 471-503.

Leave a Comment