Write a feedback loop that regulates blood sugar levels in an individual who starts out with high blood sugar?
High blood sugar levels are caused by many things:after meals,increased glycogenolysis,increased glucogenesis.Increased sugar levels stimulate beta cells of pancreas releasing insulin in more amounts.Insulin enhances absorption of glucose into cells,increases conversion of glucose to glycogen in liver i.e. glycogenesis,decrease glycogenolysis etc. Therefore,it is a negative feedback loop. Increased sugar levels - release of insulin - enhanced absorption of glucose - decrease levels of sugar.
Negative feedback loop-regulates blood sugar- someone starting with high blood sugar?
In short a negative feedback loop is to maintain homeostasis. Homeostasis bodily balance and is the whole purpose of the negative feedback loop. For example: Homeostasis is maintained but the process of : "Blood glucose level rises (ie. after eating meal) → pancreas’ beta cells release insulin into blood → target cells (muscles, liver, other organs) take up glucose; liver converts glucose to glycogen→ blood sugar level drops or if level too low (ie. skipping meal)→ pancreas’ alpha cells release glucagon into blood→ liver breaks down glucogen and releases glucose into blood → blood glucose level rises" As you said. What it means by regulates is that is is keeping the blood glucose level within it's safe/healthy limits. Too high is not good, too low is not good, so homeostasis servers to regulate bodily functions.
Using Insulin as an example, what is meant by negative feed back?
negative feedback is when a high stimulation causes a response which decreases the stimulus. for example when your blood sugar is high, this is sensed by some receptors which send impulses to the brain, which in turn sends an impulse to the pancreas cells to release insulin hormone. the insulin causes a decrease in blood sugar level.therefore as i said the response causes a decrease in the stimulus (this is the normal functioning....of course for diabetics this is not what happens)
Explain homeostasis and negative feed back to control of sugar?
Negative feedback involves regulation of a certain condition between the confines of set points. The best analogy is an air conditioning system in your home - the air conditioner works to keep the temperature of your house at a comfortable temperature. If it gets to hot, temperature receptors receive the information that triggers the air conditioning to turn on. However, if the house gets too cold, then the temperature receptors trigger the air conditioning to turn off. It's all about balance and maintaining a comfortable living environment. Negative feedback systems in your body operate very much the same way. Regulation of the concentration of blood glucose is one such example of negative feedback in your body. Your body strives to have about 90 mg glucose/100 mL (analogous to this is the confines of temperature with the air conditioning in the house, for example, you may want to keep the temperature between 68 and 72 degrees). When blood glucose levels rise, for example, after eating a meal rich in carbohydrates, beta cells of the pancreas release insulin into the blood. Insulin is a hormone that causes the cells of the body to take up more glucose - for example, the liver takes up glucose and converts it to a storable form of energy called glycogen. As glucose is taken out of the blood and converted, the concentration of blood sugar lowers, therefore restoring the concentration to its acceptable limits. When blood glucose levels decrease, alpha cells of the pancreas release the hormone glucagon into the bloodstream. This hormone triggers body cells (such as the liver) to release glucose. The liver is triggered to break down glycogen (the storable version of glucose) back to the active form glucose to be released into the blood. As a result, the blood sugar raises back to its regular limits.
Can someone give me an example of negative and positive feedback?
In negative feedback, the response to a stimulus tends to decrease or eliminate the stimulus. Most of the major hormones in the human body are regulated by negative feedback. For example, insulin... high levels of glucose in the blood trigger the release of this hormone. It triggers cells (especially in the liver and skeletal muscle) to take up and store sugar frome the blood. Result? Less sugar in the blood. In positive feedback, the response to a stimulus tends to increase the stimulus. A prime example is the hormone oxytocin. Its release is stimulated by a baby's suckling at a mother's breast. It causes the "letdown" reflex, so milk is released to the baby. The baby tastes the milk, thinks, "Yum! That's good!" and suckles more... which causes more oxytocin release, which causes more milk release... etc.
Describe how a negative feedback mechanism can help control a metabolic pathway.?
A negative feedback mechanism would inhibit the production of a hormone such as insulin or glucagon. If the blood sugar level rose to high the mechanism would inhibit glucagon release and cause release of insulin.
Under what conditions is the hormone insulin released and from which anatomical structure?
Insulin is a hormone that's produced by the beta cells (islets of Langerhans) of the pancreas in response to a rise in blood glucose levels. The rise in blood glucose levels occurs when glucose is absorbed through the walls of the intestines into the bloodstream after carbohydrates are broken down during the digestive process. One disease that's affected by this breakdown in the negative feedback loop is diabetes mellitus. In type 1 diabetes a build up of excess glucose in the bloodstream occurs because there's either a considerable lack of insulin being produced, or no insulin being produced. This occurs because the body's own immune system, for some reason, sees the beta cells as an invading force and sets out to destroy them. In type 2 diabetes a build up of excess glucose in the bloodstream occurs because the body's cells are resistant to the effects of insulin that is still being produced. All animals, including humans, require insulin to 'unlock' the body's cells so that glucose can enter them. Glucose is the main source of 'fuel' for our body's cells to create energy, thereby keeping us alive. In type 1 diabetes, insulin is always required, either by injection or by an insulin pump, as well as dietary control and exercise, is used to control the condition. In type 2 diabetes, dependent on how early the condition is caught, controlled diet and exercise is used to control the condition. This may also require oral medications, which work in different ways ... some stimulate the pancreas to produce more insulin, some lower the body's cells resistance to insulin, and some work in a combination of two or more ways to lower blood glucose levels ... and yet further advanced stages of type 2 diabetes require insulin injections plus a continuation of oral medications.
How the negative feedback controls blood glucose levels?
Your hypothalamus has glucose detecting neurones. when your blood sugar level is high the hypothalamus stimulates insulin production. Insulin converts glucose to glycogen. This decreases the blood sugar level and the change is detected by the hypothalamus. It then stops stimulating insulin production. This 'switching off' of the hormone is negative feedback. If if didn't occur, your blood sugar would drop dramatically, making you hypoglycaemic (explained here: http://en.wikipedia.org/wiki/Hypoglycemia)