Biology

When you respond to your peers you should attempt to provide robust feedback and to engage in conversation with your classmates.  The following questions might help you to provide useful feedback:

Is information in the discussion correct?

Do you agree with the identification of homeostatic mechanism parts that your classmate has identified?

Did you find any additional information about the example that you can share?

Emily Pountney

Chosen Topic: Body Temperature

Homeostasis is the phenomenon during which the human body attempts to achieve an equilibrium and maintain a constant internal environment through a series of physiological processes. For this discussion, I have chosen to focus on body temperature and, more specifically, what happens when the body temperature increases.

Regulation of body temperature illustrates a homeostatic mechanism because the human body undergoes a series of physiological processes in order to maintain a temperature range of 97-99 degrees Celsius. If the bodys temperature rises above or drops below this temperature range, thermoreceptors in the body send signals to the brains heat loss center in the anterior hypothalamus. This area produces signals that are sent to the rest of the body to increase sweat secretions and increased vasodilation in the blood vessels to bring the bodys temperature back into the suitable range. When the body experiences a decrease in temperature (below 97 degrees Celsius), then thermoreceptors stimulate the heat gain center in the posterior hypothalamus. The hypothalamus, in turn, increases the activity of the sympathetic nervous system, increases adrenaline, may initiate involuntary shivering to produce heat, and decreases blood flow in the blood vessels (vasoconstriction) to help prevent heat loss. Through these processes, the bodys temperature is increased back into the suitable range through the production of heat and prevention of further heat loss.

Stimulus: change in body temperature (increase in temperature for this example)

Receptor: thermoreceptors

Control Center: Hypothalamus (more specifically, the anterior hypothalamus)

Effector: sweat glands

Expected results: decrease in body temperature/cooling

If there was a breakdown in the homeostatic mechanism for body temperature, the body would likely overheat or freeze (hypothermia). Individuals who have impaired thermoregulation would likely have to rely on external means of regulating their temperature and avoid/engage in certain behaviors in an attempt to consciously regulate their internal temperature.