When body temperature increases above the normal range, thermoreceptors in the skin and hypothalamus detect the increase in body temperature. The heat-loss center of the hypothalamus is activated, which sends signals to blood vessels and sweat glands. In response, blood vessels in the skin dilate and sweat glands release sweat. Determine the part of this negative feedback loop that serves as the effector(s).

-blood vessels and sweat glands
-thermoreceptors
-body temperature
-hypothalamus

The correct answer is:

-blood vessels and sweat glands  

Explanation:

Homeostasis is the maintenance of a steady internal, physical, and chemical environment in a living system, and some mechanisms play out in bringing about this maintenance, which includes negative feedback mechanism among other things.

A Negative feedback mechanism is one in which the product or output of the system goes into the system to counteract the effect of the system. The negative feedback loop has several steps which are listed in order below:

1. stimulus

2. sensor

3. control

4. effector

Using the temperature regulation mechanism in this question, let us identify each of the steps:

When body temperature (stimulus) increases above the normal range, thermoreceptors (sensor) in the skin and hypothalamus detect the increase in body temperature. The heat-loss center of the hypothalamus (control) is activated, which sends signals to blood vessels and sweat glands (effector). In response, blood vessels in the skin dilate and sweat glands release sweat.

From the example above, the stimulus is the agent that induces a change in the steady state of the body, initiating the kick-off of the mechanism, in this case, temperature is the stimulus, next, the thermoreceptors detect this change, hence is a sensor, which relates the signal to the heat-loss center of the brain which is the control center, because it does the major function of the direct reversal of the change that started the system. Finally the effectors are the components that act directly to cause a change in reversing the change, in this case, the blood vessels dilate releasing making room for more internal body temperature to be dissipated and the skin produces sweat, which cools to directly reduce body temperature.