The receptor component is responsible for detecting changes in the physiological parameter.
Explanation:
Physiological parameters, such as heart rate, blood pressure, body temperature, serum levels of various stress hormones (e.g. cortisol) and immunological functions (e.g. suppression of lymphocyte activity) can be used to assess welfare. Measurement of many of these parameters requires invasive monitoring techniques.
The receptor is the sensing component that monitors and responds to changes in the environment, either external or internal. Receptors include thermoreceptors, and mechanoreceptors. These are those components of the control system which are responsible for detecting changes in the physiological parameter.
