The Homeothermic animals Are those that have the ability to maintain their internal body temperature relatively constant.
The temperature of these animals is maintained regardless of the temperature variations of the surrounding environment. They are also known as warm-blooded animals or thermoregulators.
This capacity is given by a process known as thermoregulation. It allows them to maintain their body temperature in a range between 36 ° and 42 °, depending on the species to which the animal belongs.
Birds and mammals are the two major groups that make up this classification. In these animals, this ability is fundamental for the development of a great variety of biochemical reactions and physiological processes that are related to the normal functioning of its metabolism and to its survival.
Likewise, this ability also allows homeothermal animals to adapt to survive in geographically extreme areas such as poles and deserts.
The emperor penguin, for example, lives in Antarctica, where the temperature can drop to -60 ° C and the fénec (desert fox) lives in the deserts of the Sahara and Arabia, where the temperature reaches 59 ° C.
Process of thermoregulation in homeothermic animals
Thermoregulation is the phenomenon by which homeotherms can maintain their body temperature constant despite the thermal fluctuations of the environment in which they live.
This is produced by the balance between production and heat loss versus the thermal stimuli of the environment. That is, it is the natural response of the animal's organism to the climatic demands of its habitat to maintain the internal body temperature adequate for its survival.
To achieve this balance requires a high degree of energy consumption that is possible thanks to the activation of different control mechanisms and a central control system. The mechanisms of regulation are of two types: detection mechanisms and response mechanisms.
Detection mechanisms are those that receive and send information about temperature changes to the central control system. They are made up of the peripheral nerve endings and detection nerve points in the marrow and the Hypothalamus .
The central control system, for its part, is in charge of processing the information and generate the answers that will allow to maintain the vital body temperature of the animal. In homeothermal animals this function is fulfilled by the hypothalamus.
Response mechanisms are responsible for keeping the internal body temperature constant. They include the processes of thermogenesis (heat production) and thermolysis (heat loss). These mechanisms can be of two types: physiological and behavioral.
Depending on the species, the homeotherms have a normal body temperature (eg for polar bear 38 ° C, for elephant 36 ° C, for most birds 40 ° C, etc.).
This temperature is maintained at these levels thanks to the normal metabolic processes of the organism. It is what is known as termoneutral temperature range.
However, when body thermal levels in these animals rise or fall to critical levels, special response mechanisms are activated that involve increasing the ratio of metabolic expenditure to generating heat or preventing heat loss.
Mechanisms of response in thermoregulation
There are mechanisms of response in thermoregulation that are common to all homeothermal animals, but some are specific to each species.
Many of them are manifested in the animal's physiology or behavior (winter coat, hibernation, etc.). In general terms, these responses occur within two processes: thermal radiation and evaporation.
Interaction of the body with the environment
The first response consists of the interaction of the body with the environment or the body with another object or body and allows both production and heat loss.
An example of this can be observed in the grouping of the emperor penguins during the colder seasons. By joining together, it allows them to generate enough heat to maintain the internal body temperature at the neutral level, regardless of the extreme cold of the environment.
Another example is the coat of hair or plumage that some animals develop during the winter seasons and that allows them to withstand the low temperatures (the ptarmigan, the wolves, etc.).
Perspiration
The second response relates to the loss of heat through the evaporation of water through the pores of the skin (perspiration) or some other mechanism that allows the body to cool.
For example, dogs perspire through the pads of their paws and use their tongue to pant to release heat. In the case of pigs, they wallow in mud to cool themselves, because they have few sweat glands.
Other thermoregulation mechanisms
- Piloerection or ptiloerection . It is the erection of hairs or feathers and occurs in cold situations in order to maintain the air between the skin and the environment to generate an insulating barrier that prevents heat loss.
- Hibernation . It consists of a state of deep sleep in which the vital functions (breathing, heartbeat, temperature) of the animal are drastically reduced. The animal survives by consuming stored caloric reserves during periods of activity.
- Physiological changes . Variations of the weight and change of fur or plumage during the different seasons of the year to adapt to the ambient temperature.
Some homeothermic animals and their mechanisms of thermal regulation
Elephant
Due to its large size, the elephant generates large amounts of heat. To keep your body temperature stable and to release heat, the elephant uses its ears.
Elephants can not sweat, so to cool their ears move. By moving them, the blood vessels dilate or contract at will, causing the blood to cool in this area, and then be dispersed throughout the body and thus refresh it.
The structure of their skin also allows them to regulate the heat. The deep cracks and channels of the skin that trap moisture and small bristles that generate tiny currents of air contribute to maintain the body temperature of the animal.
The polar bear
This animal whose habitat has temperatures that can reach -30 ° C, keeps its internal body temperature constant thanks to its extensive layers of skin, fat and fur.
The camel
The camel has mechanisms of thermoregulation related to its physiognomy. Its long legs and long neck give it the necessary height to increase its possibilities of cooling.
Besides its coat, which is a kind of wool, helps to isolate your skin from the ambient heat. Likewise, the fact that most of your body fat is stored in your humps and not between your skin and muscles, allows you to take better advantage of the ambient air to cool.
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