Homeostasis Thermoregulation

Homeostasis - Thermoregulation

Homeostasis is the ability of a cell or organism to maintain a stable internal environment despite fluctuating external environmental conditions. An animal will maintain this state of equilibrium through adjustment mechanisms that keep the conditions of its cells and body within a narrow range (SOC 2 n.d.). Homeostasis is crucial to the survival of an organism, by maintaining a stable environment, it enables cells to be functioning optimally, giving an organism the best chance of surviving to a reproductive age, followed by reproduction which maintains or increases the size of a population.

An example of homeostasis is Thermoregulation. This is an organism's ability to maintain its internal temperature, keeping
The purpose of Thermoregulation is to balance the input and output of heat so that (for humans) their core temperature remains constant at a “set point” of approximately 37 degrees celsius (SOC 1 n.d.). It is crucial for the survival of endotherms, organisms that maintain an internal temperature independently of their external environment (Encyclopaedia Britannica 2018). The main heat source for endotherms is produced during respiration (see model 2 &3). Respiration occurs in the mitochondria of cells, it is where oxygen and glucose combine to form chemical energy (36 ATP), water and, as a waste product, carbon dioxide. During the final reaction of respiration, the electron transport chain which takes place in the cristae of mitochondria, heat energy is released (SOC 3 n.d. slide 34). This heat energy is the main source of heat for endotherms, such as a cyclist taking part in the ‘Cancer Society Tour
This is a homeostatic control system. In the negative feedback mechanism (refer to model 1), a change is detected which activates mechanisms to reverse the change. In the context of Thermoregulation, whenever the internal temperature of the cyclist deviates from what is considered normal (approximately 37 degrees celsius), ie. gets too high or too low, the negative feedback system kicks in. For example, when body temperature decreases, a process is initiated to increase it. And vice versa, when the body temperature increases, a process is initiated to decrease it (Pass Biology n.d. para 10). The components that make up this process known as the negative feedback system are the Stimulus, Receptors, Control Centre, Effectors and Response. A stimulus is a detectable change in the internal or external environment of an organism (SOC 1 n.d.). In thermoregulation, the stimulus can be an increase or decrease in body temperature. As a cyclist participating in the ‘Cancer Society Tour Aotearoa 2018’ cycles, their muscles require an increased amount of ATP. Feedback signals initiate the increased rate of respiration, which results in an increased demand of oxygen and more carbon dioxide is produced. Heat is also produced as a bi-product. Hence, when the cyclist is cycling their core temperature is likely to exceed 37 degrees celsius which initiates a Thermolytic (cooling) response (see model