Body Temperature Regulation
Body temperature regulation is the process by which the body maintains a stable internal temperature despite external fluctuations. This is achieved through a combination of physiological and behavioral mechanisms, such as shivering to generate heat or sweating to cool down. The hypothalamus in the brain plays a central role in coordinating these responses to ensure the body's temperature remains within a narrow range.
6 Key excerpts on "Body Temperature Regulation"
eBook - ePubUnderstanding Fever and Body Temperature
A Cross-disciplinary Approach to Clinical Practice
- Ewa Grodzinsky, Märta Sund Levander, Ewa Grodzinsky, Märta Sund Levander(Authors)
- 2019(Publication Date)
- Palgrave Macmillan(Publisher)
...© The Author(s) 2020 E. Grodzinsky, M. Sund Levander (eds.) Understanding Fever and Body Temperature https://doi.org/10.1007/978-3-030-21886-7_5 Begin Abstract 5. Thermoregulation of the Human Body Ewa Grodzinsky 1 and Märta Sund Levander 2 (1) Department of Pharmaceutic Research, Linköping University, Linköping, Sweden (2) Department of Nursing, Linköping University, Linköping, Sweden Ewa Grodzinsky (Corresponding author) Märta Sund Levander Email: [email protected] End Abstract The body is an open system that needs to protect its internal environment from its surroundings. At the same time it is dependent on its surroundings for the exchange of oxygen, nutrients, waste products, and heat. These conflicting demands need particularly physiological mechanisms to maintain a stable and balanced internal environment, so-called homeostasis. The complex physiological self-regulatory mechanisms and processes required to achieve homeostasis are maintained by specialized organs and organ systems in the body. The ability to regulate and exchange body heat is essential for survival in humans. Regulation of body temperature operates via a neural feedback system. Sensory inflows indicating cold or heat from several different parts of the body, such as the skin and internal organs, reach specialized neurons located in the central nervous system, chiefly in the hypothalamus. The hypothalamus integrates the incoming sensory information and transmits neural and hormonal signals, initiating various kinds of physiological activity. The physiological activities represent, in broad terms, heat gain, or, alternatively, heat loss, and thus maintain an appropriate body temperature. Organs or organ systems besides the nervous system that are the main actors in regulation of body temperature are the cardiovascular system, the sudomotor control system, and skeletal muscles...
eBook - ePubThe Neurobiology of Behavior
An Introduction
- Gordon J. Mogenson(Author)
- 2018(Publication Date)
- Routledge(Publisher)
...For example, a rat exposed to the cold may build a nest or in the laboratory may press a lever to turn on a heat lamp; at the same time, there will be peripheral vasoconstriction to reduce heat loss and increased discharge of the sympathetic nervous system and increased output of thyroid hormones to increase metabolic heat production. It seems appropriate to begin, therefore, with a consideration of these two kinds of thermoregulatory responses before directing our attention later in the chapter exclusively to behavioral thermoregulatory responses. In the later sections, we deal first with the characteristics and determinants of thermoregulatory behaviors as a perspective for considering what is known about the neural substrates. Thermoregulatory behavior has been selected as the first motivated behavior to be considered in detail, because it is closely associated with homeostasis. It is the example par excellence of a “homeostatic drive,” occurring in response to a deviation in core body temperature. BODY-TEMPERATURE REGULATION 1 There is an optimal temperature for the functioning of body cells—regulation of body temperature is one of the conditions of homeostasis. In man, body temperature is maintained at 37°-38°C with minor variations. A deep body temperature above 43°-44°C is lethal in man and many mammals, and a body temperature below 25°C is incompatible with life. The regulation of body temperature within rather narrow limits means that heat being continuously produced by body cells must be balanced by heat loss. There are physiological mechanisms regulated by hormones and the autonomic nervous system that control both heat production and heat loss (Figure 3.1). These are considered briefly in the first part of this section...
- Karen Birch, Keith George, Don McLaren(Authors)
- 2004(Publication Date)
- Routledge(Publisher)
...A series of acclimatization adjustments exists for most environments and these may protect against the deleterious effects of exercise combined with environmental stress (acclimation refers to the development of acclimatization in artificial surroundings such as a heat chamber in a laboratory). As exercise in hot or cold climates is now fairly commonplace it is important to understand the intricacies of thermoregulation and its control. Thermal balance Physiological and biochemical processes in the human body are temperature sensitive to the point where a small rise in temperature in specific parts of the body may lead to injury, loss of function and eventually death. To prevent this humans control very tightly internal temperature and are thus described as homeothermic. The maintenance of body temperature is a complicated issue when you consider the vast amount of heat produced by the body (e.g. during exercise) and also the interaction with an environment that may see significant temperature changes. It is therefore a key role of various organs (e.g. cardiovascular system) and the thermoregulatory controlling centers in the hypothalamus in the brain to maintain thermal balance. Although temperature in different sites within the body will differ (e.g. skin surface vs. deep body) an important role for the body is to maintain body (core) temperature within the range c. 36–38°C. Maintenance of core temperature, and thus thermal balance, is achieved through a range of processes (see Fig. 1 fig. 1 Heat balance in the human body.). Specifically these are metabolic heat production, radiation, conduction, convection and evaporation. Heat gain Heat gain in the body is primarily derived from all metabolically active tissues where the conversion of chemical energy to kinetic energy is only 15–25% efficient. As energy cannot be destroyed the rest is released as heat...
eBook - ePub- Ken Parsons(Author)
- 2019(Publication Date)
- CRC Press(Publisher)
...This is called homeostasis, and was described by Claude Bernard in his work on what he called the “internal milieu.” All mammals, including humans, practice homeostasis, and in terms of maintaining a relatively constant internal temperature, they are called homeotherms. People “attempt” to maintain an internal body temperature of around 37°C and usually within the range 36.5°C–37.5°C. To achieve this, all people have a system of thermoregulation. Human Thermoregulation Heat stress occurs when the environment creates conditions where the internal body temperature of a person has a tendency to rise. Generally, the human response to the heat stress is to attempt to increase heat loss from the body to the environment or reduce heat gain to the body from the environment. This thermoregulation occurs as two types. One is mainly conscious, where a person will respond to discomfort or dissatisfaction by taking action (e.g., moving away, adjusting clothing, opening a window, or switching on a fan). This is called behavioral thermoregulation or an adaptive approach. The second is an unconscious, automatic, and continuous system called physiological thermoregulation. The systems work together and are shown in Figure 2.1. FIGURE 2.1 A diagrammatic representation of human thermoregulation. Behavioral regulation is controlled by the conscious cortex and mostly requires a conscious decision. Physiological regulation is continuous and automatic and controlled by the hypothalamus. Physiological Thermoregulation The physiological system of thermoregulation can be conveniently divided into two parts, the controlled system and the controlling system. The controlled system is often called the passive system as it represents the nonactive part of the human body. That is the skin, fat, muscle, bone, organs, head, hands, feet, arms, legs, trunk, lungs, blood, lymph, and so on...
eBook - ePub- Tonks Fawcett, Roger Watson(Authors)
- 2014(Publication Date)
- Routledge(Publisher)
...Chapter 3 Body Temperature Regulation Aim To understand the regulation of body temperature. Learning outcomes This chapter will enable the reader to: • explain what is meant by body temperature; • describe and explain the source of body heat; • recognise the importance of maintaining a constant body temperature; • explain the mechanisms whereby body heat can be lost; • explain the mechanisms whereby body heat can be conserved; • recognise the implication any deviation in temperature control might have for patient well-being. Introduction The regulation of body temperature is another excellent example of a homeostatic mechanism that has already been referred to in Chapters 1 and 2. The human body is designed to work at a particular temperature and this temperature is maintained during health. If the temperature rises there are mechanisms for losing heat from the body and if the temperature falls there are mechanisms for generating and conserving heat in the body. However, as with all homeostatic mechanisms, they work within limits. What is temperature? Temperature is, strictly speaking, a measure of the movement of molecules. However, as the most common way to change the movement of molecules is by the application and removal of heat, we use temperature as a proxy measure for heat. Temperature is measured using the Kelvin scale and 0 Kelvin (—237 degrees centigrade) is referred to as absolute zero because, at this temperature, no molecular motion is possible. In other words, it is not possible to obtain a colder temperature than absolute zero. In everyday life, temperature is measured using arbitrary scales and in the United Kingdom and Europe the Celsius or Centigrade scale is used. This scale is zero at the temperature where water freezes (equivalent to 237 K) and 100 at the temperature where water boils (Figure 3.1). The normal body temperature, measured at the core of the body, is approximately 37 °C...
eBook - ePubVital Signs for Nurses
An Introduction to Clinical Observations
- Joyce Smith, Rachel Roberts(Authors)
- 2011(Publication Date)
- Wiley-Blackwell(Publisher)
...The patient may complain of feeling cold and hungry, as the body sends messages that it needs more fuel to fight the infection (Mains et al., 2008). The body also relies on human behaviour to help it control the body temperature. Feeling cold and shivery may cause the patient to want to put on extra clothing or bedding to maintain the body temperature (Mains et al., 2008). Another mechanism used to control thermoregulation is the brain's ability to control the size of the diameters of the blood vessels, causing them to either vasodilate or constrict. A higher temperature will trigger the body to release a hormone called adrenaline. Adrenaline will act on the heart to make it beat faster and therefore increase the pulse rate. It will also act on the peripheral blood vessels and cause them to vasoconstrict. This action means that the blood can remain as close to the core of the body and away from the surface of the skin, which in turn reduces the amount of heat loss (Roberts, 2008). As we have discussed previously, body temperature is a measure of the body's ability to produce and get rid of heat; it represents the balance of the metabolic processes taking place within the human body (Dougherty and Lister, 2008) and helps to maintain homeostasis. The body is very good at regulating its temperature within a narrow, safe range in spite of large variations in temperature outside the body. To create heat, the body relies on the metabolic activities of the major organs. Some illnesses and diseases can also impact on the range of body temperature – for example, a damaged liver, which in normal health produces lots of heat and energy, will be less efficient and so the body will function at a cooler body temperature. To release heat, the body uses the skin and sweat glands to cool the body down through processes called convection and conduction (Tortora and Derrickson, 2006; Dougherty and Lister, 2008)...
