Saturday, August 7, 2010

Can you give me an example of a controlled variable, sensor, controlled center, and effector?

Variable - Sodium ion levels in the blood stream


Sensor - the kidney


Control Center - the kidney contains the set-point for sodium levels - specifically the juxtaglomerular apparatus which releases Renin


Effector - adrenal gland's secretion of aldosterone to increase Na+ uptake in the loop of Henle (increases blood Na+ concentration, decreases urine Na+ concentration)Can you give me an example of a controlled variable, sensor, controlled center, and effector?
If you are talking about in the human body, a variable that is controlled is the body temperature. The sensor in humans is the hypothalamus, and its nervous system output varies depending on the temperature, increasing in high temperature, and decreasing in low temperature. The brain (the hypothalamus is part of the brain) controls the dilation of blood vessels. If the body is cold, the blood vessels contract and release less heat to the environment, and vice versa. If the body remains below the set point temperature, the body will start shivering - the by product of muscle contraction is heat. The blood vessels and muscles would be some of the effectors.

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