Homeostasis is the ability of a system or living organism to adjust its internal environment to maintain a stable equilibrium; this is achieved by complex biological functions.

  • Positive feedback is described as the process in which the body senses a change and activates mechanisms that accelerate or increase that change. An example of positive feedback is childbirth, where the uterine stretching triggers the secretion of a hormone, oxytocin, which stimulates uterine contractions and speeds up labor.


  • Negative feedback is described as when the body senses an internal change and activates mechanisms that reverse, or negate, that change. An example of negative feedback is body temperature regulation. If blood temperature rises too high, special neurons will sense it and send signals to the hypothalamus. Other nerve centers are notified, which will in turn send signals to the blood vessels of the skin. As these blood vessels dilate, more blood flows close to the body surface and the excess heat radiates from the body. If this doesn’t do the job, the brain activates sweating. On the other hand, if the blood temperature falls too low, this is also sensed by the hypothalamus and signals are sent to the cutaneous arteries (those supplying the skin) to constrict them. Warm blood is then retained deeper in the body and less heat is lost from the surface. If this is inadequate, then the brain activates shivering. Shivering releases energy and warms the body back up.

Below is an odd (but creative) video I found pertaining to positive/negative feedback. Enjoy!

  • The body is composed of two different fluid compartments, extracellular and intracellular. Intracellular is the fluid inside of the cells while extracellular is the fluid outside (plasma and interstitial fluid). Intracellular fluids make up about 2/3 of the body’s water and is primarily made up of proteins and essential minerals. Extracellular fluids make up the other 1/3 of the body’s water and is comprised of interstitial fluid (fluids surrounding cells), plasma and transcellular fluid (digestive juices, mucus, etc.).

  • As a nurse, I will be treating a plethora of different conditions and problems. In order to treat a patient with a biological dysfunction, it’s essential to know how the body functions normally. It’s imperative to know how all systems work and how the body maintains its normal functioning in order to notice an abnormality. An example I've had recently is working with a patient with an infection process. Once stabalized, we must ensure that the patient's infection is not reoccuring or getting worse. We do this by checking the patient's vital signs, as a discrepancy would be the first indicator that something is wrong. (In other words, a break in homeostasis). An elevated temperature is often caused by infection.

  • Question: I described negative feedback about, and another way that it works is insulin control. "Why is it essential that insulin be regulated in the human body?" If we didn't regulate the amount of insulin our body produces, we would suffer serious consequences. If we produce too much insulin, we wouldn't have enough blood glucose (sugar) left in our blood. We would then experience hypoglycemia with symptoms including anxiety, sweating, tremors, and nausea. If left untreated, hypoglycemia can also lead to clumsiness, dizziness, and/or fainting. If still left untreated, seizures, coma or death can occur. If a person doesn't produce enough insulin, they can easily become hyperglycemic. Symptoms of hyperglycemia include headache, increased thirst, and increased urination. If hyperglycemia is left untreated, ketoacidosis can occur, which can led to a coma. Our bodies only demand a certain quantity of essential molecules, and if these molecules aren't regulated the consequences can be detramental.