Practical: Temperature Regulation
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Abstract
Temperature regulation or thermoregulation is defined as the control of temperature(s) of a body under finite environmental conditions. The regulation is obtained through the control of heat gain and loss between the body and the immediate environs through the utilization of automatic and behavioral mechanism. Various chemical reactions are involved in the metabolism of living organisms. The reactions change chemical energy form one form to the other and some heat lost (Eckert, 2004). The paper in details examines the complex homeostatic system regulating the body temperature using comparatively measurements of temperature at different body location and under different physiological conditions. The capacity by which organisms preserve their proper heat under different environmental conditions is important on determining the life sustainability at adverse conditions and so the importance of the practical.
Introduction
Thermoregulation is the ability of an organism to maintain its normal temperature regardless of the changes in the external environment. The process is among the aspects of homeostatic; a dynamic stability condition between the internal and external temperatures. Suppose the body cannot main a constant internal temperatures, then a condition referred to as heat stroke occurs. When temperature reduces below expected levels, then a condition known as hypothermia occurs. In the practical, three beakers of water with different temperatures were used (one beaker contained water at 400C, 150C and 30oC (Eckert, 2004). The different water temperatures were important since it could help determine the response of the body when subjected to different weather conditions. The temperature of the body was measured in an interval of 2 minutes for 6 minutes. This was to thoroughly monitor the response of the water on the body temperature and how the rate at which the body resumes to its normal temperature. Both hands were dipped in 400C and 150c at once. This made comparison easier and done at the same time. The resulted were plotted ad and so it was easy to determine or identify the rate of changes of temperatures and the reaction of the cells to different temperatures.
Methods and materials
The sensation of transferring limbs from different ambient temperatures was determined into the same ambient temperature.
Three large beakers (500ml) were picked and then labeled A, B and C.
A B C
15oC 30oC 40oC
I placed my left hand in in beaker A (15oC), and right in beaker C (40oC). This was for duration of 2 minutes.
After 2 minutes, I transferred both handles to beaker B (30oC).
The body responses were recorded (in regard to the heat felt at both hands).
Then hands were then returned to their initial beakers, left hand in in beaker A (15oC), and right in beaker C (40oC) and then the process repeated once again. The average temperature was determined. The temperatures were recorded for ten minutes on both left and right hands and the following result was obtained.
Assumptions
Other environmental factors did not have effects on the experiment
The body internal variations never affected the outcome of the experiment. The person was healthy.
Results
Table 3 show the result of exercise (worming and codling biceps)
At Rest 33.1 ºC
Hot Cold
2 min 33.8 ºC 32.5 ºC
4 min 34.0 ºC 32.0 ºC
6 min 34.2 ºC 29.3 ºC
8 min 34.4 ºC 28.2 ºC
10 min 34.1 ºC 28.0ºC
The graph below shows the variations in temperature of the two hands in different beakers (due to different temperatures).
Form the graph, its is evident that the temparture of hand dipped in cold water decraesed and the tenperature of hand dipped in hot water increased. The maximum and minimu temperatures were obtained after 8 minutes. At 8 minutes, the hand heat recptors had detecetd the improvised environmental condition and so had to act. After ten minutes the graph started curvign to its former point. Howver, the period cannot be detremined isnce the exptreiment was between 0 minutes and 10 minutes.
Discussion
Basal metabolic rate is the minimum calorific requirement to sustain life when an organism is at the state of rest. At this state minimum energy is produced and so the temperature (33.1 ºC).
Eternal temperatures also have effects on the metabolic rates. When an organism is exposed to cold environment, the body reacts by increasing the metabolic rate to supply the extra heat needed to maintain the body’s internal temperature. A short exposure to high temperatures has less impact on the body’s metabolism as it is compensated by increase in the heat lost to the environment form the body. When an organism is exposed to heat for long the metabolic rate increases.
Enzymes are protein-based biological catalysts needed by human body cells to speed up chemical reactions and are affected by temperature variances. Their roles range from speeding up chemical reactions in the cells to ridding off waste products from the cells. Enzymes speed up all chemical reactions that take place in cells of human body. Metabolic enzymes speed up conversion of the digested food into new body structures such as flesh, muscle, nerves, glands and bones with the release on energy (Eckert, 2004).
With enzyme-catalyzed reactions, although the rate at which the reaction comes to equilibrium increases with temperatures, there is a second effect of temperatures; denaturation of the enzyme protein, leading to irreversible loss of activity. However, dipping the hands in water of 400C cannot denature the enzymes and so the possibility of the experiment. The hands were thus never burnt or harmed.
In hot conditions
In the beaker containing hot water, the body temperature was lower than the water temperature. The sweat glands produced sweat which passed to the skin surface to be lost and hence decrease in temperature. This caused heat loss through sweat evaporation. Conversely, the hair on the skin lay flat to allow for the escape of heat. This is caused by small muscles under the skin surface (known as errectorpili muscles) to relax and thus preventing their hair follicles from erecting (Rhodes, 2003). The air circulation is increased when the hair lays flat and thus maximum flow of air and so heat loss through convection as well as radiation. The water temperature was above the normal body temperature and sweating was the only physiological way to it to loose excess heat (Borque, 2002).
On the other hand in reducing the excess heat, arterioles vasodilation must have occurred as well. This is the process of relaxation of smooth muscles n arteriole walls permitting raised flow of blood in the arteries. The process made the blood to main flow in the superficial capillaries in the skin raising heat loss through convection and radiation. The hand was thus able to react to the environmental condition.
In cold conditions
In beaker A, sweating was stopped. The tiny muscles under the skin surface (errectorpili muscles) contracted and thus lifting the hair follicle and making them stand upright. This made hair stand and hence blocking the way through which heat could escape. Maximum heat was thus retained in hand dipped in beaker A. this is what caused goose pimple visible on the hand dipped in beaker A as there are not many hair and the muscles that contracted could be easily seen.
Arterioles carrying blood beneath the skin contracted (through the process called vasoconstriction) and blood was redirected away from the skin towards the inner and warmer body parts (Rhodes, 2003). The blood exposed to the surface thus reduced and the heat loss through convention reduced as well. Les blood flowed near the surface and hence reduced heat loss. This helped retain much heat. The hand was thus able to react to the environmental condition through took more than ten minutes to reverse the heating process.
Lowering environmental temperatures
Considering lowering the temperature or an organism from for example 290C to 150C has various effects. To begin with, the subject relies entirely on purely physical mechanism to maintain a constant temperature, the metabolic rate remained constant. However, at about 270C, the physical mechanisms are no longer capable of maintaining a constant body temperature on their own, and the metabolic rates starts going up. The condition is known as lower critical temperature, the lowest temperature at which physical mechanism alone can regulate the body temperature (Borque, 2002). As the outside temperature is further lowered, the metabolic rate continuous to increase until eventually chemical mechanism breaks down. At this point, the lower lethal temperature is reached (the experiment however, never reaches this stage).
Increasing environmental temperature
The various mechanisms promoting heat loss succeed in keeping the body temperatures constant, but there comes a point when the ability of the body to regulate its temperature breaks down (high critical temperature) and various depending on the humidity. Once the high critical temperature is reached the metabolic rate starts going up and this continues until environmental temperature rises. No longer protected by the body’s cooling processes, chemical reactions in the cells become subject to the temperature rule, doubling their rate every time the temperature increases by 100C. The experiment does not reach this point however. The curve after the 10th minute curves to back to their original reading and this is an indication that the temperatures (from 150C-400C) never denatured the enzymes.
Relevance of the experiment
Each animal species appears to have a distinct temperatures range, within which there is an optimum temperature for metabolism. Moreover, the temperature tolerance of species differs, so that some have a wide temperature range, some are thermophilic and others are cold blooded. Throughout, climates changes, any particular niche will be occupied by a succession of species each succeeding the other as their optima are exceeded. Temperatures are therefore fundamental factor in controlling the metabolic rate. It is thus essential to determine the range of temperatures in which an organism can operate (Rhodes, 2003). This will minimize the random death of majority of the animals when taken to other regions or when subjected to various conditions (temperature). The low critical temperatures, has been determined for a number of different species, and it has been found that animals living in cold areas have a lower critical temperatures than those living in warm places. For example kangaroo rat has a low critical temperature of about 310C, whereas for artic fox it may be as low as -400C (Eckert, 2004). Moreover, below the low critical temperature the curve of metabolic rate against environmental temperature is much less steep, and the lower lethal temperature much lower, for cold-dwellers than for warm dwellers. The findings reflect the fact that in cold environments the animals have better insulation mechanism than those living in warmer places, an important aspect of survival.
Experiment limitations
Environmental factors like draught must have affected the outcome of the experiment.
Left and right hands have different qualities and characteristics since left is characterized by many arteries and left veins. This must have affected heat retention and lost.
The experiment only considers one person. There is no control experiment as well. This means that any variation in the body of the person greatly affected the outcome of the experiment and conclusions were make form the errors.
Errors obtained through reading of thermometers. The thermometer accuracy is only up to the second decimal place and so the less accurate results.
Conclusion
Behavioral as well as chemical control is essential to organisms. Some animals have poor control over their body temperatures. After ten minutes the graph showing the effects of heat on the body started recovering its normal readings. This must be after the heat gained form the hot water was lost and the hand was slowly responding to the increased heat. The reverse happened to the left hand. After immersion, the body fully acquired the water temperature after 8 minutes (when the effects were maximum). The body started slowly responding to the change and hence the rise in the graph after 10 minutes. The experiment has confirmed that human hands can tolerate a temperature of from 150C to 400C. the process of reverting to the also started ten minutes later and so the human capability of dealing with adverse temperatures.
Bibliography
Eckert, R. et al. 2004. “Body Size and Metabolic Rate.” Animal Physiology: Mechanisms and Adaptations. pp. 563 – 566.
Rhodes, S. 2003. Biology 360: Comparative Animal Physiology: A Lab Manual.
Borque, H. (2002). Causes, signs, and effects of sugar in the body. National Institute Of Justice Press: Washington.
