feedback or negative feedback in homeostasis is a key process for the various systems of the body to maintain their normal state. The normal state of the body is called the baseline state and homeostasis is, in short, the maintenance of this baseline state. Negative feedback cannot help keep the body exactly at baseline values, but it does work by keeping the body within a range of values considered normal and within which it can perform its functions.
For example, if the body temperature rises too much, processes such as sweating are triggered to cool the body. If your body temperature drops too much, you start shivering to help raise your temperature with muscle movement. It’s called negative feedback (sometimes abbreviated NFB). negative evaluation) because the reaction is in the opposite direction to the received signal: in this example, a temperature rise signal is received and an action is taken to reduce it and vice versa.
How it works?
There are normally three parties involved in negative feedback: the so-called receiver Control Center and the so-called effector. The receptor is the organ or tissue that intervenes in the process of negative feedback, recording the values of some variable of the organism; these variables can be very different, for example temperature, blood pressure or blood glucose concentration. The information collected by the receiver is continuously sent to the control center. When the values received go outside the normal ranges, the control center will send orders to Organs effector organs to start working in a certain way that helps to return the variable values to normal values at baseline.
Let’s look, for example, as a process of negative feedback to maintain blood pressure. The receptors are, in this case, pressure-sensitive nerve endings and are found mainly in veins and arteries near the heart and head. These receptors send nerve impulses to the part of the brain that regulates heartbeat; that part of the brain would be the control center. From this regulatory center, signals are sent back to the effector organ, in this case the heart, so that it increases or decreases its rhythm and thus regulates blood pressure. (Note: many other factors are involved in blood pressure regulation, only one has been discussed to simply illustrate the concept of negative feedback in homeostasis).
A similar concept is used in psychology. Negative feedback in psychology is useful for understanding the basic motivations of individuals. For example, when a person is deprived of food, he becomes increasingly hungry. The feeling of being hungry would here be a negative feedback mechanism to get the person to eat and bring the organism to the basal nutritional state. When a person eats, the feeling of hunger disappears through the feedback mechanism itself that informs the regulatory center that it has already been eaten.
What would happen if there was no negative feedback?
As we have seen, the organism needs to keep biological parameters within a certain range, often a narrow range. Outside this range, more or less serious problems and consequences for health can even mean death.
For example, under normal conditions, the body temperature is between 37.2 and 37.6 ºC. Outside of these values, body temperature can fluctuate for several reasons that can be considered normal, but if it drops below 33°C, hypothermia will occur, and if it rises above 42°C, hyperthermia will occur. Both hypothermia and hyperthermia are situations that can trigger serious consequences up to death. In other cases, the effects may not be visible in the short term, but they can still produce serious effects in the long term. For example, hypertension may not develop noticeable symptoms for patients, but it can be the cause of heart attacks and other fatal cardiovascular diseases.
Therefore, negative feedback is the main control mechanism of homeostasis and, as such, it is essential to keep the different parameters of the organism between the values in which it can perform its functions. If negative feedback didn’t exist, we would die. In fact, when negative feedback control mechanisms fail, medicine must be turned to to help the body maintain homeostasis.