Download Homeostasis of Glucose Metabolism: This image

Name _________________________________________________________ date ___________ period ____
Directions:
1. Number the paragraphs
2. Circle the key words: Imbalance, feedback, mechanism, regulate, diabetes
3. On a separate sheet of paper that you will staple this worksheet, write the definition of each of the key
words noted in #2 above.
4. Read the article and underline or highlight the main idea from each of the paragraphs.
5. Find several examples of homeostatic imbalance from the article. Make a T-Chart listing the example of
the imbalance on one side and a description of the imbalance on the other side.
Homeostatic Imbalance
The ability of a system or living organism to adjust its internal environment and maintain a stable
equilibrium such as the ability of warm-blooded animals to maintain a constant internal temperature are
examples of homeostasis. Positive and negative feedbacks are equally important for the healthy functioning of
one's body and to restore and maintain the body's physiological systems within a normal functional range.
Complications can arise if any of the two feedbacks are affected or altered in any way leading to homeostatic
imbalance.
Many diseases are a result of homeostatic imbalance. As an organism ages, it will lose efficiency in its
control systems. The inefficiencies gradually result in an unstable internal environment that increases the risk
for illness. In addition, homeostatic imbalance is also responsible for the physical changes associated with
aging. Even more serious than illness and other characteristics of aging is death. Heart failure has been seen
where nominal negative feedback mechanisms become overwhelmed and destructive positive
feedback mechanisms then take over.
Some examples of diseases that result from a homeostatic imbalance include diabetes, dehydration,
hypoglycemia, hyperglycemia, gout, and any disease caused by a toxin present in the bloodstream. All of these
conditions result from the presence of an increased amount of a particular substance. In ideal circumstances,
homeostatic control mechanisms should prevent this imbalance from occurring. However, in some people, the
mechanisms do not work efficiently enough or the quantity of the substance exceeds the levels at which it can
be managed. In these cases, medical intervention is necessary to restore the balance or permanent damage to
the organs may result. Most homeostatic regulation is controlled by the response from the nervous system or
the release of hormones into the bloodstream by the endocrine system.
Homeostatic imbalance occurs when the human body’s internal environmental variables become
disturbed. The condition can be attributed to a number of factors which include the aging of the person’s
organs and the organ’s control systems or feedback mechanisms, which can cause them to malfunction or not
perform up to the standard that has been normal throughout the majority of the person’s lifetime.
Homeostasis can also be disturbed when certain pathological situations are present in the body and
overwhelm the controls and mechanisms that have been behaving in a healthy and life-sustaining manner.
The stability of the homeostatic mechanism is achieved, for the most part, by a series of mechanisms that
balance the input and output of signals, chemicals, and fluids. Most diseases can be at least partly attributed
to the presence of homeostatic imbalance within the system.
The inefficiencies in homeostatic imbalance caused by the aging process are the main culprit in normal
signs of aging like the breakdown of skin, the dulling of mental processes, and the decreased ability of the
person to perform physical activity. In addition, the inevitable increases in in homeostatic imbalance lead to
many of the serious diseases associated with the aging population like diabetes, gout, and heart failure. In the
example of heart failure, the negative feedback systems associated with heart and circulatory function that
normally regulate the body are overwhelmed and destructive positive feedback mechanisms take over,
contributing to the serious and sometimes fatal nature of the condition Homeostatic control mechanisms
control the imbalance of toxins in the bloodstream as well. When increased amounts of substances are
introduced into the system and homeostatic imbalance is present, as in the example of gout, a buildup of toxic
uric acid is the primary cause of the painful and chronic symptoms of the disease.
One specific example is related to diabetes. Normally the human body performs blood sugar
regulation by regulating and maintaining constant levels of glucose throughout the day, even after a 24-hour
fast. During long periods of fasting, glucose levels are reduced only very slightly. Insulin, secreted by the beta
cells of the pancreas, effectively transports glucose to the body's cells by instructing the cells to keep the
glucose for their own use. If the glucose inside the cells is high, the cells will convert it to the
insoluble glycogen to prevent the soluble glucose from interfering with cellular metabolism. Ultimately, this
lowers blood glucose levels; insulin helps to prevent hyperglycemia. When insulin is deficient or cells become
resistant to it, diabetes occurs. Glucagon, secreted by the alpha cells of the pancreas, encourages cells to
break down stored glycogen or convert non-carbohydrate carbon sources to glucose via gluconeogenesis, thus
preventing hypoglycemia. The kidneys are used to remove excess water and ions from the blood. These are
then expelled as urine. The kidneys perform a vital role in homeostatic regulation in mammals, removing the
body's waste products such as excess water, salt, and urea from the blood.
Homeostasis of Glucose Metabolism: This image illustrates glucose metabolism over the course of a day. Homeostasis may become imbalanced if the pancreas is overstressed, making it unable to balance glucose metabolism. This could lead to diabetes.
When no homeostatic imbalance is present, the body is able to regulate its blood sugar levels
efficiently. When diabetes mellitus is present, however, after a person has eaten a meal, the insulin needed
for regulation is either totally absent or present in inadequate levels. Low or absent levels of insulin caused by
dysfunction of the homeostatic mechanism make it harder for all cells in the body to absorb the hormone.
When insulin is not absorbed, blood glucose levels can remain dangerously high.
In the case of this type of diabetes, as with other pathologies associated with homeostatic imbalance,
medical intervention is often times needed to correct and regulate input and output ratios in order to restore
balance. Gout can be treated with medications to reduce the buildup of uric acid. The common condition of
dehydration is often times attributed to homeostatic imbalance as well, and is treated simply by introducing
electrolyte-rich fluids back into the system to reestablish homeostasis.