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How Do Insulin And Glucagon Help Maintain Homeostasis?

Blood Glucose Regulation

Blood Glucose Regulation

Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin is a hormone produced by the pancreas that regulates glucose levels in the blood. How glucose is regulated Glucose level Effect on pancreas Effect on liver Effect on glucose level too high insulin secreted into the blood liver converts glucose into glycogen goes down too low insulin not secreted into the blood liver does not convert glucose into glycogen goes up Use the animation to make sure you understand how this works. You have an old or no version of flash - you need to upgrade to view this funky content! Go to the WebWise Flash install guide Glucagon – Higher tier The pancreas releases another hormone, glucagon, when the blood sugar levels fall. This causes the cells in the liver to turn glycogen back into glucose which can then be released into the blood. The blood sugar levels will then rise. Now try a Test Bite- Higher tier. Diabetes is a disorder in which the blood glucose levels remain too high. It can be treated by injecting insulin. The extra insulin allows the glucose to be taken up by the liver and other tissues, so cells get the glucose they need and blood-sugar levels stay normal. There are two types of diabetes. Type 1 diabetes Type 1 diabetes is caused by a lack of insulin. It can be controlled by: monitoring the diet injecting insulin People with type 1 diabetes have to monitor their blood sugar levels throughout the day as the level of physical activity and diet affect the amount of insulin required. Type 2 diabetes Type 2 diabetes is caused by a person becoming resistant to insulin. It can be controlled by diet and exercise. There is a link between rising levels of obesity (chronic overweight) and i Continue reading >>

Regulation Of Body Processes

Regulation Of Body Processes

Hormonal Regulation of the Excretory System The contrasting actions of antidiruetic hormone and aldosterone work to regulate the level of water in the body. Learning Objectives Explain how the actions of different hormones regulate the excretory system Key Takeaways The hypothalamus monitors the amount of water in the body by sensing the concentration of electrolytes in the blood; a high concentration of electrolytes means that the level of water in the body is low. Antidiuretic hormone (ADH), produced by the hypothalamus and released by the posterior pituitary, causes more water to be retained by the kidneys when water levels in the body are low. ADH effects water retention by creating special channels for water, called aquaporins, inside the kidneys so that more water can be reabsorbed before it is excreted. Aldosterone, produced by the adrenal cortex, causes the retention of water in the body by increasing the levels of sodium and potassium ions in the blood, which causes the body to reabsorb more water. When blood pressure is low, the enzyme renin is released, which cleaves the protein angiotensinogen into angiotensin I, which is further converted into angiotensin II. Angiotensin II signals the adrenal cortex to release aldosterone, which then increases the retention of sodium ions, enhancing the secretion of postassium ions, resulting in water retention and an increase in blood pressure. renin: a circulating enzyme released by mammalian kidneys that converts angiotensinogen to angiotensin-I that plays a role in maintaining blood pressure mineralocorticoid: any of a group of steroid hormones, characterised by their similarity to aldosterone and their influence on salt and water metabolism electrolyte: any of the various ions (such as sodium or chloride) that regulat Continue reading >>

Blood Sugar Regulation

Blood Sugar Regulation

Most cells in the human body use the sugar called glucose as their major source of energy. Glucose molecules are broken down within cells in order to produce adenosine triphosphate (ATP) molecules, energy-rich molecules that power numerous cellular processes. Glucose molecules are delivered to cells by the circulating blood and therefore, to ensure a constant supply of glucose to cells, it is essential that blood glucose levels be maintained at relatively constant levels. Level constancy is accomplished primarily through negative feedback systems, which ensure that blood glucose concentration is maintained within the normal range of 70 to 110 milligrams (0.0024 to 0.0038 ounces) of glucose per deciliter (approximately one-fifth of a pint) of blood. Negative feedback systems are processes that sense changes in the body and activate mechanisms that reverse the changes in order to restore conditions to their normal levels. Negative feedback systems are critically important in homeostasis, the maintenance of relatively constant internal conditions. Disruptions in homeostasis lead to potentially life-threatening situations. The maintenance of relatively constant blood glucose levels is essential for the health of cells and thus the health of the entire body. Major factors that can increase blood glucose levels include glucose absorption by the small intestine (after ingesting a meal) and the production of new glucose molecules by liver cells. Major factors that can decrease blood glucose levels include the transport of glucose into cells (for use as a source of energy or to be stored for future use) and the loss of glucose in urine (an abnormal event that occurs in diabetes mellitus). Insulin and Glucagon In a healthy person, blood glucose levels are restored to normal level Continue reading >>

Glucose Metabolism And Regulation: Beyond Insulin And Glucagon

Glucose Metabolism And Regulation: Beyond Insulin And Glucagon

Insulin and glucagon are potent regulators of glucose metabolism. For decades, we have viewed diabetes from a bi-hormonal perspective of glucose regulation. This perspective is incomplete and inadequate in explaining some of the difficulties that patients and practitioners face when attempting to tightly control blood glucose concentrations. Intensively managing diabetes with insulin is fraught with frustration and risk. Despite our best efforts, glucose fluctuations are unpredictable, and hypoglycemia and weight gain are common. These challenges may be a result of deficiencies or abnormalities in other glucoregulatory hormones. New understanding of the roles of other pancreatic and incretin hormones has led to a multi-hormonal view of glucose homeostasis. HISTORICAL PERSPECTIVE Our understanding of diabetes as a metabolic disease has evolved significantly since the discovery of insulin in the 1920s. Insulin was identified as a potent hormonal regulator of both glucose appearance and disappearance in the circulation. Subsequently, diabetes was viewed as a mono-hormonal disorder characterized by absolute or relative insulin deficiency. Since its discovery, insulin has been the only available pharmacological treatment for patients with type 1 diabetes and a mainstay of therapy for patients with insulin-deficient type 2 diabetes.1–7 The recent discovery of additional hormones with glucoregulatory actions has expanded our understanding of how a variety of different hormones contribute to glucose homeostasis. In the 1950s, glucagon was characterized as a major stimulus of hepatic glucose production. This discovery led to a better understanding of the interplay between insulin and glucagon, thus leading to a bi-hormonal definition of diabetes. Subsequently, the discovery of Continue reading >>

Module 7 /feedback Loops

Module 7 /feedback Loops

Describe the components of a feedback loop. Compare and contrast positive and negative feedback in terms of the relationship between stimulus and response. Remember that homeostasis is the maintenance of a relatively stable internal environment. When a stimulus, or change in the environment, is present, feedback loops respond to keep systems functioning near a set point, or ideal level. Typically, we divide feedback loops into two main types: positive feedback loops, in which a change in a given direction causes additional change in the same direction. For example, an increase in the concentration of a substance causes feedback that produces continued increases in concentration. negative feedback loops, in which a change in a given direction causes change in the opposite direction. For example, an increase in the concentration of a substance causes feedback that ultimately causes the concentration of the substance to decrease. Positive feedback loops are inherently unstable systems. Because a change in an input causes responses that produce continued changes in the same direction, positive feedback loops can lead to runaway conditions. Some positive feedback loops can be harmful. However, there are a few instances in which positive feedback helps to maintain homeostasis. One such example is blood clotting. When a blood vessel is broken, a clot begins to form and clotting factors are activated at the site. The activation of clotting factors continues into a chain reaction until bleeding within the vessel stops. In this instance, the set point is the point at which no blood leaves the site. The release of clotting factors stimulates further release of clotting factors, until the blood is so heavily clotted that no blood leaves the vessels. Some positive feedback loops are Continue reading >>

Insulin Vs Glucagon

Insulin Vs Glucagon

Insulin and glucagon have both similarities and differences. Both are hormones secreted by the pancreas but they are made from different types of cells in the pancreas. Both help manage the blood glucose levels in the body but they have opposite effects. Both respond to blood glucose levels but they have opposite effects. Each of us has insulin and glucagon in our systems because it is a strict requirement that the blood sugar level in the body is kept in a narrow therapeutic range. You need both insulin and glucagon to respond to various levels of glucose in the bloodstream. While insulin responds and is secreted by the pancreas upon having high glucose levels in the bloodstream, glucagon responds and is secreted by the pancreas upon having low glucose levels in the bloodstream. This maintains homeostasis in the body and keeps the blood sugar stable at all times. Function of Insulin Insulin is a protein-based hormone that is secreted by the beta cells inside the pancreas whenever the pancreas senses that the blood sugar is too high. Low levels of insulin are constantly being secreted into the bloodstream by the pancreas, even when blood glucose levels are normal. After you eat a meal, the glucose from the food you eat is taken up by the gastrointestinal tract, increasing the level of glucose in the blood. When this happens, the beta cells get activated and more insulin is secreted to help decrease the glucose levels, primarily by helping the glucose enter the cells to be used as cellular fuel. When the glucose level in the blood decreases, insulin levels by the islet (beta) cells of the pancreas return to a baseline status. In response to the elevated insulin level, the various cells of the body bind to insulin and the insulin facilitates the transfer of glucose from t Continue reading >>

Role Of Insulin And Glucagon In Blood Sugar Balance

Role Of Insulin And Glucagon In Blood Sugar Balance

1. ROLE OF INSULIN AND GLUCAGON IN BLOOD SUGAR BALANCE INTRODUCTION: The hormones insulin and glucagon work together to efficiently maintain a balanced blood sugar level. They do this when insulin encourages the liver and muscle cells to absorb any extra glucose there is and then convert it into glycogen. WHAT IS INSULIN? : Insulin is a peptide hormone, produced by beta cells of the pancreas, and is central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, skeletal muscles, and fat tissue to absorb glucose from the blood. In the liver and skeletal muscles, glucose is stored as glycogen, and in fat cells (adipocytes) it is stored as triglycerides. Insulin stops the use of fat as an energy source by inhibiting the release of glucagon. With the exception of the metabolic disorder diabetes mellitus and metabolic syndrome, insulin is provided within the body in a constant proportion to remove excess glucose from the blood, which otherwise would be toxic. When blood glucose levels fall below a certain level, the body begins to use stored sugar as an energy source through glycogenolysis, which breaks down the glycogen stored in the liver and muscles into glucose, which can then be utilized as an energy source. As a central metabolic control mechanism, its status is also used as a control signal to other body systems (such as amino acid uptake by body cells). WHAT IS GLUCAGON? : Glucagon generally elevates the amount of glucose in the blood by promoting gluconeogenesis and glycogenolysis. Glucose is stored in the liver in the form of glycogen, which is a starch-like polymer chain made up of glucose molecules. Liver cells (hepatocytes) have glucagon receptors. When glucagon binds to the glucagon receptors, the liver 2. cells convert th Continue reading >>

Insulin And Glucagon

Insulin And Glucagon

- [Voiceover] Metabolism is just the flow of energy throughout the body. Energy enters our body when we eat food, and that food is then absorbed in three different forms. It can be absorbed as amino acids, so, things that make up proteins, so, you'd imagine meat would have a lot of amino acids. Or they can be absorbed as fats, so these are lipids, or fatty acids and so your greasy, fried food is pretty rich in fats. Or they can be absorbed in carbohydrates, or I'll just write "carbs" here, which you have a lot of in ice cream or other sweet things. Each of these things deliver energy into your GI tract. Your stomach, and your intestines, which can then be absorbed and sent elsewhere for use. Now carbohydrates are one of the main currencies for energy, so let's focus on that, and we'll do so by starting with glucose, which is the most basic form of carbohydrates. In fact, it's considered a simple sugar. Now, there are two main hormones that control the availability of glucose throughout the body. And they're at a constant tug of war with each other. One of them, which you've heard of probably is called "insulin." Insulin regulates that storage of glucose, as we'll talk more about in a minute, and the other guy on the end of the rope, is a hormone called "glucagon." Glucagon regulates the release of glucose from storage. And it's pretty important that we have enough glucose available in the blood. Because, for example, the brain uses about 120 grams of glucose per day. And that's a lot, because it comes out to be about 60 to 70% of all the glucose that we eat in a day. But to put it in terms that I think you and I appreciate a little more, 120 grams of glucose comes out to be about 250 M&Ms, in a single day! Now that's a lot of M&Ms. So you can see why it's really importa Continue reading >>

Normal Regulation Of Blood Glucose

Normal Regulation Of Blood Glucose

The human body wants blood glucose (blood sugar) maintained in a very narrow range. Insulin and glucagon are the hormones which make this happen. Both insulin and glucagon are secreted from the pancreas, and thus are referred to as pancreatic endocrine hormones. The picture on the left shows the intimate relationship both insulin and glucagon have to each other. Note that the pancreas serves as the central player in this scheme. It is the production of insulin and glucagon by the pancreas which ultimately determines if a patient has diabetes, hypoglycemia, or some other sugar problem. In this Article Insulin Basics: How Insulin Helps Control Blood Glucose Levels Insulin and glucagon are hormones secreted by islet cells within the pancreas. They are both secreted in response to blood sugar levels, but in opposite fashion! Insulin is normally secreted by the beta cells (a type of islet cell) of the pancreas. The stimulus for insulin secretion is a HIGH blood glucose...it's as simple as that! Although there is always a low level of insulin secreted by the pancreas, the amount secreted into the blood increases as the blood glucose rises. Similarly, as blood glucose falls, the amount of insulin secreted by the pancreatic islets goes down. As can be seen in the picture, insulin has an effect on a number of cells, including muscle, red blood cells, and fat cells. In response to insulin, these cells absorb glucose out of the blood, having the net effect of lowering the high blood glucose levels into the normal range. Glucagon is secreted by the alpha cells of the pancreatic islets in much the same manner as insulin...except in the opposite direction. If blood glucose is high, then no glucagon is secreted. When blood glucose goes LOW, however, (such as between meals, and during Continue reading >>

Homeostasis Of Glucose Levels: Hormonal Control And Diabetes

Homeostasis Of Glucose Levels: Hormonal Control And Diabetes

Homeostasis According to the Centers for Disease Control and Prevention, there are almost 26 million people in the United States alone that have diabetes, which is 8.3% of the total U.S. population. With so many Americans suffering from diabetes, how do we treat all of them? Do all of these people now need insulin shots, or are there other ways to treat, or prevent, diabetes? In order to answer these questions, we must first understand the fundamentals of blood glucose regulation. As you may remember, homeostasis is the maintenance of a stable internal environment within an organism, and maintaining a stable internal environment in a human means having to carefully regulate many parameters, including glucose levels in the blood. There are two major ways that signals are sent throughout the body. The first is through nerves of the nervous system. Signals are sent as nerve impulses that travel through nerve cells, called neurons. These impulses are sent to other neurons, or specific target cells at a specific location of the body that the neuron extends to. Most of the signals that the human body uses to regulate body temperature are sent through the nervous system. The second way that signals can be sent throughout the body is through the circulatory system. These signals are transmitted by specific molecules called hormones, which are signaling molecules that travel through the circulatory system. In this lesson, we'll take a look at how the human body maintains blood glucose levels through the use of hormone signaling. Homeostasis of Blood Glucose Levels Glucose is the main source of fuel for the cells in our bodies, but it's too big to simply diffuse into the cells by itself. Instead, it needs to be transported into the cells. Insulin is a hormone produced by the panc Continue reading >>

Pancreatic Regulation Of Glucose Homeostasis

Pancreatic Regulation Of Glucose Homeostasis

Go to: The pancreas is an exocrine and endocrine organ The pancreas has key roles in the regulation of macronutrient digestion and hence metabolism/energy homeostasis by releasing various digestive enzymes and pancreatic hormones. It is located behind the stomach within the left upper abdominal cavity and is partitioned into head, body and tail. The majority of this secretory organ consists of acinar—or exocrine—cells that secrete the pancreatic juice containing digestive enzymes, such as amylase, pancreatic lipase and trypsinogen, into the ducts, that is, the main pancreatic and the accessory pancreatic duct. In contrast, pancreatic hormones are released in an endocrine manner, that is, direct secretion into the blood stream. The endocrine cells are clustered together, thereby forming the so-called islets of Langerhans, which are small, island-like structures within the exocrine pancreatic tissue that account for only 1–2% of the entire organ (Figure 1).1 There are five different cell types releasing various hormones from the endocrine system: glucagon-producing α-cells,2 which represent 15–20% of the total islet cells; amylin-, C-peptide- and insulin-producing β-cells,2 which account for 65–80% of the total cells; pancreatic polypeptide (PP)-producing γ-cells,3 which comprise 3–5% of the total islet cells; somatostatin-producing δ-cells,2 which constitute 3–10% of the total cells; and ghrelin-producing ɛ-cells,4 which comprise <1% of the total islet cells. Each of the hormones has distinct functions. Glucagon increases blood glucose levels, whereas insulin decreases them.5 Somatostatin inhibits both, glucagon and insulin release,6 whereas PP regulates the exocrine and endocrine secretion activity of the pancreas.3, 7 Altogether, these hormones regul Continue reading >>

How Insulin And Glucagon Work

How Insulin And Glucagon Work

Insulin and glucagon are hormones that help regulate the levels of blood glucose, or sugar, in your body. Glucose, which comes from the food you eat, moves through your bloodstream to help fuel your body. Insulin and glucagon work together to balance your blood sugar levels, keeping them in the narrow range that your body requires. These hormones are like the yin and yang of blood glucose maintenance. Read on to learn more about how they function and what can happen when they don’t work well. Insulin and glucagon work in what’s called a negative feedback loop. During this process, one event triggers another, which triggers another, and so on, to keep your blood sugar levels balanced. How insulin works During digestion, foods that contain carbohydrates are converted into glucose. Most of this glucose is sent into your bloodstream, causing a rise in blood glucose levels. This increase in blood glucose signals your pancreas to produce insulin. The insulin tells cells throughout your body to take in glucose from your bloodstream. As the glucose moves into your cells, your blood glucose levels go down. Some cells use the glucose as energy. Other cells, such as in your liver and muscles, store any excess glucose as a substance called glycogen. Your body uses glycogen for fuel between meals. Read more: Simple vs. complex carbs » How glucagon works Glucagon works to counterbalance the actions of insulin. About four to six hours after you eat, the glucose levels in your blood decrease, triggering your pancreas to produce glucagon. This hormone signals your liver and muscle cells to change the stored glycogen back into glucose. These cells then release the glucose into your bloodstream so your other cells can use it for energy. This whole feedback loop with insulin and gluca Continue reading >>

Question: Describe The Way In Which Insulin And Glucagon Work Together To Maintain Blood-glucose Homeostasi...

Question: Describe The Way In Which Insulin And Glucagon Work Together To Maintain Blood-glucose Homeostasi...

Describe the way in which insulin and glucagon work together to maintain blood-glucose homeostasis. Include in your answer a discussion of the ways in which insulin can enhance the effects of Growth Hormone. Your answer should : begin with a short introductory paragraph; cover the topic in two, three, four or more distinct paragraphs; end with a concluding paragraph that ties your answer together The cells in the body are affected by the amount of glucose circulating in the blood Therefore; if the concentration of glucose in the body is increased or decreased the body would be greatly affected. The homeostasis of blood glucose levels is based... view the full answer Continue reading >>

Insulin Lowers Blood Glucose By Increasing Glucose Uptake In Muscle And Adipose Tissue And By Promoting Glycolysis And Glycogenesis In Liver And Muscle.

Insulin Lowers Blood Glucose By Increasing Glucose Uptake In Muscle And Adipose Tissue And By Promoting Glycolysis And Glycogenesis In Liver And Muscle.

Glucose Homeostasis and Starvation Glucose Homeostasis: the balance of insulin and glucagon to maintain blood glucose. Insulin: secreted by the pancreas in response to elevated blood glucose following a meal. Insulin:Glucagon Ratio: everything that happens to glucose, amino acids and fat in the well fed state depends upon a high insulin to glucagon ratio. Glucagon: a fall in blood glucose increases the release of glucagon from the pancreas to promote glucose production. Glucose Tolerance Test: evaluates how quickly an individual can restore their blood glucose to normal following ingestion of a large amount of glucose, i.e. measures an individuals ability to maintain glucose homeostasis Diabetic: can not produce or respond to insulin so thus has a very low glucose tolerance Glucose, Protein and Fat Pathways: Obese Individuals: even with prolonged medically supervised fasting have plasma glucose levels that remain relatively constant even after three months. Glucose / Fatty Acid / Ketone Body Cycle: "explains the reciprocal relationship between the oxidation of glucose versus fatty acids or ketone bodies" Principal Hormone Effects on the Glucose-Fatty Acid Cycle: Under conditions of CHO stress (lack of CHO's): There is depletion of liver glycogen stores Fatty acids are mobilized from adipose and their rate of oxidation by muscle is increased, which in turn decreases glucose utilization. Glucagon signals fat mobilization. Under conditions of plentiful CHO's: Fatty acid release by adipose is reduced by insulin, thus decreasing fatty acid oxidation. Glucose use by the muscles increases. These responses stabilize blood glucose. The regulatory effect of fatty acid oxidation on glucose utilization is logical: 1) the small reserves of CHO in the body 2) the obligatory requireme Continue reading >>

Understanding The Role Of Energy Homeostasis In Diabetes

Understanding The Role Of Energy Homeostasis In Diabetes

Introduction The prevalence of diabetes and obesity has been on the rise for several decades and research has demonstrated that other parts of the body, including the cardiovascular system and kidneys, can be affected by diabetes. The key to understanding the relationship between diabetes and these other areas begins with the role of energy homeostasis in diabetes. At the same time, investigators are utilizing various biomarkers that have been shown to help further diabetes and obesity research. The key to understanding the relationship between diabetes and these other areas begins with the process of energy homeostasis and the important biomarkers used in today’s research. Role of Energy Homeostasis in Diabetes Energy homeostasis is a well-regulated process that depends on the coordination between feeding behavior and energy expenditure. The control of energy homeostasis in humans has received much attention in recent years due to alterations caused by the onset of conditions such as obesity and diabetes. A variety of organs tightly control energy homeostasis including the: The pancreas is one of the most important organs involved in maintaining energy homeostasis because it is responsible for the secretion of insulin and glucagon. Insulin and glucagon are two counter regulatory hormones that control the systemic concentration of glucose, a metabolic intermediate used by cells as the primary source of energy. If glucose homeostasis is thrown off balance, a diabetic state develops. What is Diabetes? Type 1 Diabetes (T1D, Juvenile Diabetes) Type 1 diabetes is an auto-immune disease that results in the destruction of β-cells in the pancreas1. With the destruction of β-cells, the body cannot produce enough insulin to maintain energy homeostasis. Onset of type 1 diabete Continue reading >>

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