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What Regulates Body Temperature in Humans

Batul Nafisa Baxamusa Apr 19, 2019
Have you ever wondered what regulates body temperature in humans? Thermoregulation is a survival trick that helps humans to maintain a constant body temperature. Let's go into the details of temperature regulation of the human body.
Humans are homeotherms like most mammals. This means that we are warm blooded animals and have to regulate our internal body temperature. The ideal temperature for a human body is 37°C. If there is even a 5°C drop or rise in body temperature, it could spell doom for the human being.
As you can see, the temperature range within which a human can survive is very narrow. This makes one wonder what regulates body temperature in humans. This is especially quite intriguing as the external environmental temperature ranges are totally different from the internal body temperature.
What makes us know that we are too cold or too hot? Which signals are sent by the brain to keep our body temperature constant? Many times, menstruation in women, strenuous exercise and fever causes a rise in body temperature. How does the body manage to regulate temperature when it moves away from the set point? Let's find out all the answers.

How Does Temperature Changes Affect the Human Body?

As mentioned earlier, the core internal body temperature for humans is 37°C (+/- 0.5°C). The core body temperature changes according to the external as well as environmental factors. Thus, fever, exercising and menstruation affect the core temperature up to 3°C. Cold and external temperature can decrease body temperature by 1°C.
If the body temperature rises or falls below these temperature ranges, it leads to many serious complications. The skin temperature too varies according to environmental and metabolic factors. There are temperature receptors within the skin that helps detect changes and trigger the central nervous system to compensate for the rise or fall in temperature.
If the temperature rises to above the normal temperature range, it leads to changes in the protein molecules (denaturation). However, the amino acid molecules are not affected. Body temperature around 41.5°C is called hyperpyrexia. This condition occurs during sepsis, Kawasaki syndrome, etc.
The cells are injured at an extremely high temperature i.e., above 45°C. It leads to severe brain damage, heart and lung damage. If the body temperature is not regulated soon, it will lead to death. The severity of the injury depends on the temperature level and the amount of time heating lasts.
Cold too can cause tissue injury. Freezing causes damage of the cells mechanically. Cells also get damaged due to changes in physicochemical environment in the cytoplasm. Temperature changes also affect the biological function of the cells as well as biochemical reactions occurring in the body.

How Does the Human Body Regulate Heat?

As we move into the details of what modulates body temperature, it is important to understand how our body produces heat. Our body requires a lot of food to regulate many functions in the body. One of these functions include production of energy.
The energy produced from food is converted to heat by two methods. Metabolic activity and environmental energy are the two ways via which energy is converted into heat. The body uses various mechanisms to maintain heat levels and retain heat in the body.
Muscular activity and shivering helps in converting the stored chemical energy into heat. Thus, it helps in increasing the heat through skeletal muscles from where it is passed on throughout the body. Thyroid hormones too help maintain basal metabolic rate in body cells. This leads to thermogenesis due to increase in conversion of chemical energy into heat.
Hormones like epinephrine, norepinephrine along with certain sympathetic effects from the cells help in regulating body heat. These effects include contraction of body hair muscles that lead to trapping of air near the skin and thus reducing heat loss.
Increase in metabolic rate leads to production of more energy that is converted to heat. Vasoconstriction helps in reducing the amount of heat radiated into the environment from the skin.

How is the Human Body Temperature Reduced?

Just like there are different ways to increase or maintain body heat, there are different mechanisms that help the body get rid of excessive heat. The body increases the rate of transfer of heat by increasing conduction rate or transfer rate.
Conduction rate of the body temperature is movement of the heat from the core to the surface. Transfer rate of the body is movement of the heat from the body surface into the environment. This is carried out by radiation, conduction and evaporation. This is the reason why we tend to get all sweaty and flushed when we feel hot.
The skin is the major organ that helps in thermoregulation of the body heat. Sweat glands are stimulated that lead to sweating. Evaporation of sweat gives a cooling effect to the body.
The capillary vessels present in the skin dilate and this causes a lot of blood to flow through the skin. This helps in radiating the heat into the environment from the body. Our natural breathing also helps in conduction of heat from the body into the environment which reduces the core body temperature.

Temperature Regulation in Humans

Temperature regulation means maintaining homeostasis, i.e., 'same state'. The body temperature in humans is controlled by the thermoregulatory center. It is known as the hypothalamus, located in the brain. It receives two sets of thermoreceptors from the brain and within itself.
These receptors in the hypothalamus monitor temperature in the blood that flows through the brain (core temperature). Receptors of the skin help the hypothalamus monitor the external temperature.
These temperature tips received from both sets of the thermoreceptors help the hypothalamus regulate body temperature. So, if the hypothalamus feels that there is a significant rise in temperature, you feel like switching on the AC. And if there is a drop, you tend to shiver and hunt for your sweater to cover your body.
This was some information on how the human body regulates its core temperature. The answer to what regulates body temperature in humans is the hypothalamus and various other mechanisms that help in transfer of internal and external heat.
It is important to maintain body heat or else it will affect enzymes and many regular activities in the body will cease to function. Hope you have found the answer to your question related to temperature regulation of the human body.