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Which Organ Regulates Glucose In The Blood?

Blood Sugar Control

Blood Sugar Control

The concentration of glucose in our blood is important and must be carefully regulated. This is done by the pancreas, which releases hormones that regulate the usage and storage of glucose by cells. Type 1 diabetics are unable to make sufficient quantities of one of these hormones – insulin - and must therefore control their blood sugar levels by injecting insulin, as well as by carefully controlling their diet and exercise levels. Controlling rising blood sugar It is important that blood glucose level is kept within a narrow range due to its importance as an energy source for respiration - but also because of the effects it could have in causing the movement of water into and out of cells by osmosis Having eaten a meal containing sugars or starch (eg sweets, potatoes, bread, rice or pasta), the starch and large sugars are digested down into glucose and absorbed across the small intestine wall into the bloodstream. This triggers a rise in blood glucose concentration. The pancreas monitors and controls the concentration of glucose in the blood. In response to an increase in blood glucose level above the normal level, the pancreas produces a hormone called insulin which is released into the bloodstream. Insulin causes glucose to move from the blood into cells, where it is either used for respiration or stored in liver and muscle cells as glycogen. The effect of this is to lower the blood glucose concentration back to normal. The animation below shows how this works. You have an old or no version of Flash - you need to upgrade to view this content! Go to the WebWise Flash install guide Diabetes There are two main types of diabetes: Type 1 which usually develops during childhood Type 2 which is usually develops in later life This syllabus focuses on Type 1 diabetes - whic Continue reading >>

Organ Systems Involved In Homeostasis

Organ Systems Involved In Homeostasis

Homeostasis is the process by which the body regulates its internal environment for chemical and biological processes to occur. Some of the more important variables that need to be controlled include temperature, and the levels of blood sugar, oxygen and carbon dioxide. A number of organs are involved in homeostasis, and these include the lungs, pancreas, kidneys and skin. Lungs Respiration is the process by which glucose is used to create energy. It is the most important reaction taking place within the human body and allows the creation of energy. Critical to the respiration process is the regulation of oxygen levels within the blood, which is carried out by the lungs. As respiration takes place within the body, carbon dioxide is produced and released into the blood. The level of carbon dioxide is used as an indirect measure of blood oxygen levels. Special cells in the brain detect the carbon dioxide levels in the blood, and if it is too high, nerve impulses are sent to stimulate the muscles that control breathing. The lungs then fill with air faster, increasing the amount of oxygen in the bloodstream. If carbon dioxide levels within the blood are low, the brain cells do not stimulate nerve cells, reducing the rate of breathing. Pancreas The regulation of blood-glucose levels is essential for the survival of the human body. The pancreas, a small glandular organ located close to the stomach, has a number of functions. One of the most important is the regulation of blood-sugar levels. The pancreas contains special cells known as the Islets of Langerhans that detect blood-glucose levels. If the blood-glucose levels are too high, the cells release the hormone insulin to stimulate liver, muscle and fats cells to absorb glucose from the blood and store it as glycogen, or st Continue reading >>

How Does The Liver Control Glucose In The Blood?

How Does The Liver Control Glucose In The Blood?

Your body needs a constant supply of glucose, or sugar, for cells to have energy, so it requires a readily available reservoir to keep blood glucose in balance. One of the liver’s main roles in the body is controlling the amount of glucose circulating in the blood. By storing excess glucose as glycogen and creating new glucose from proteins and fat byproducts, the liver is able to maintain balanced glucose levels in your body at all times. Video of the Day When you eat carbohydrates, the body releases glucose into the bloodstream immediately, triggering the production of insulin. The body cannot be in a state of constant consumption, so when insulin levels are high enough, the body links long chains of glucose together into a compound called glycogen, which is then stored in the liver and the muscles. The liver uses this stored glucose energy as its main reservoir for releasing glucose into the bloodstream when levels drop. Breakdown of Glycogen Blood glucose levels drop when you're not eating, such as during sleep or between meals. This low blood sugar signals the liver to produce glucose and release it back into the bloodstream. The liver favors glycogen as its primary source since it is efficiently broken down into glucose in a process known as glycogenolysis. In this process, the liver breaks the bonds that hold glucose molecules together as glycogen, degrading most but not all of the glycogen molecule. Effects of Insulin Resistance When your body is chronically subjected to high levels of blood sugar and insulin, such as after you've eaten an excessive amount of foods high in sugar, it develops a resistance to the hormone, and the liver cannot respond properly, eventually leading to type-2 diabetes if the resistance is not controlled. According to a study publish Continue reading >>

What Organ Regulates The Amount Of Glucose In The Bloodstream?

What Organ Regulates The Amount Of Glucose In The Bloodstream?

Glucose in the bloodstream provides the primary fuel for all body tissues. Blood glucose levels are highest during the digestive period after a meal. Your blood sugar is lowest when the stomach and intestines are empty. Under normal circumstances, the body tightly controls the amount of insulin in your blood. An organ called the pancreas, which is tucked behind the stomach releases the hormones insulin and glucagon to regulate blood sugar levels. Blood sugar regulation is crucial because high and low blood glucose can cause health problems. The pancreas is an elongated organ wide on one end and slender on the other end and measures about 25 centimeters in length. It has dual functions: it releases digestive enzymes, which plays a role in digestion, and it secretes hormones. Prevents High Blood Glucose Insulin plays an integral role in preventing high blood sugar. After you eat a meal and your blood-glucose rises, your pancreas senses your blood-sugar level. When the glucose in your bloodstream becomes high, the pancreas releases insulin into your bloodstream. A small clump of pancreatic cells called the ''islets of Langerhans,'' manufacture insulin. Once the insulin is in your bloodstream, it allows your cells to absorb and use glucose as a fuel source. Mediates Low Blood Sugar When you consume more carbohydrate than your body needs at the time, your body stores the extra glucose as glycogen in the liver. The pancreas continuously monitors your blood sugar levels. When glucose is low, the pancreas releases the hormone glucagon. The glucagon triggers the liver to break down glycogen and converts it back to glucose. The stored glucose enters the bloodstream and raises blood-glucose levels. This allows the body to keep blood sugar levels stable in between meals. Blood Gluc Continue reading >>

How The Body Controls Blood Sugar - Topic Overview

How The Body Controls Blood Sugar - Topic Overview

The bloodstream carries glucose-a type of sugar produced from the digestion of carbohydrates and other foods-to provide energy to cells throughout the body. Unused glucose is stored mainly in the liver as glycogen. Insulin, glucagon, and other hormone levels rise and fall to keep blood sugar in a normal range. Too little or too much of these hormones can cause blood sugar levels to fall too low (hypoglycemia) or rise too high (hyperglycemia). Normally, blood glucose levels increase after you eat a meal. When blood sugar rises, cells in the pancreas release insulin, causing the body to absorb glucose from the blood and lowering the blood sugar level to normal. When blood sugar drops too low, the level of insulin declines and other cells in the pancreas release glucagon, which causes the liver to turn stored glycogen back into glucose and release it into the blood. This brings blood sugar levels back up to normal. Continue reading >>

How Does The Human Body Regulate Its Blood Glucose Levels?

How Does The Human Body Regulate Its Blood Glucose Levels?

Once a person has eaten a meal, their digestive system will break the nutrients down into smaller components that can travel in the blood to any parts of the body that need them. Any carbohydrates in this food will be broken down into sugars (e.g. glucose). These sugars will rapidly enter the blood. At this point, it is critical for the body to use the glucose ASAP to avoid hyperglycaemia (high blood glucose) and maintain a constant blood glucose level. The glucose in the blood is therefore stored in liver and muscle cells in the form of a larger molecule called glycogen. The body is able to detect blood glucose levels via an organ called the pancreas. More specifically, it is detected by areas within the pancreas called islets of Langerhans. In this region there are 2 types of cells. Beta-cells and alpha-cells. Beta-cells will detect high blood glucose (e.g. after a meal) and secrete insulin. Insulin is a hormone that will help the liver and muscle cell uptake more glucose and convert it to glycogen, thus lowering the overall blood glucose levels. Alpha-cells will detect low blood glucose (e.g. after exercise) and secrete glucagon. Glucagon is also a hormone, but it has the role of breaking down glycogen and releasing glucose from the liver and muscle cells. This will increase the blood glucose. To provide an overview, the components within this system communicate with each other via hormones in order to provide a relatively constant blood glucose level. This maintanence of the internal environment is an example of homeostasis. Continue reading >>

Blood Sugar Regulation

Blood Sugar Regulation

Ball-and-stick model of a glucose molecule Blood sugar regulation is the process by which the levels of blood sugar, primarily glucose, are maintained by the body within a narrow range. This tight regulation is referred to as glucose homeostasis. Insulin, which lowers blood sugar, and glucagon, which raises it, are the most well known of the hormones involved, but more recent discoveries of other glucoregulatory hormones have expanded the understanding of this process.[1] Mechanisms[edit] Blood sugar regulation the flatline is the level needed the sine wave the fluctuations. Blood sugar levels are regulated by negative feedback in order to keep the body in balance. The levels of glucose in the blood are monitored by many tissues, but the cells in the pancreatic islets are among the most well understood and important. Glucagon[edit] If the blood glucose level falls to dangerous levels (as during very heavy exercise or lack of food for extended periods), the alpha cells of the pancreas release glucagon, a hormone whose effects on liver cells act to increase blood glucose levels. They convert glycogen into glucose (this process is called glycogenolysis). The glucose is released into the bloodstream, increasing blood sugar. Hypoglycemia, the state of having low blood sugar, is treated by restoring the blood glucose level to normal by the ingestion or administration of dextrose or carbohydrate foods. It is often self-diagnosed and self-medicated orally by the ingestion of balanced meals. In more severe circumstances, it is treated by injection or infusion of glucagon. Insulin[edit] When levels of blood sugar rise, whether as a result of glycogen conversion, or from digestion of a meal, a different hormone is released from beta cells found in the Islets of Langerhans in the p Continue reading >>

C2006/f2402 '11 Outline Of Lecture #16

C2006/f2402 '11 Outline Of Lecture #16

Handouts: 15A -- Lining of the GI Tract & Typical Circuit 15B -- Homeostasis -- Seesaw view for Glucose and Temperature Regulation; 16 -- Absorptive vs Postabsorptive state I. Homeostasis, cont. See handouts 15A & B & notes of last time, topic VI. A. Regulation of Blood Glucose Levels -- Seesaw View #1 (Handout 15B) B. Regulation of Human Body Temperature -- Seesaw #2 (Handout 15B) C. The Circuit View (Handout 15A) II. Matching circuits and signaling -- an example: How the glucose circuit works at molecular/signaling level Re-consider the circuit or seesaw diagram for homeostatic control of blood glucose levels -- what happens in the boxes on 15A? It may help to refer to the table below. A. How do Effectors Take Up Glucose? 1. Major Effectors: Liver, skeletal muscle, adipose tissue 2. Overall: In response to insulin, effectors increase both uptake & utilization of glucose. Insulin triggers one or more of the following in the effectors: a. Causes direct increase of glucose uptake by membrane transporters b. Increases breakdown of glucose to provide energy c. Increases conversion of glucose to 'stores' (1). Glucose is converted to storage forms (fat, glycogen), AND (2). Breakdown of storage fuel molecules (stores) is inhibited. d. Causes indirect increase of glucose uptake by increasing phosphorylation of glucose to G-P, trapping it inside cells 3. How does Insulin Work? a. Receptor: (1). Insulin works through a special type of cell surface receptor, a tyrosine kinase linked receptor; See Sadava fig. 7.7 (15.6). Insulin has many affects on cells and the mechanism of signal transduction is complex (activating multiple pathways). (2). In many ways, insulin acts more like a typical growth factor than like a typical endocrine. (Insulin has GF-like effects on other cells; is i 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 >>

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 >>

The Liver & Blood Sugar

The Liver & Blood Sugar

During a meal, your liver stores sugar for later. When you’re not eating, the liver supplies sugar by turning glycogen into glucose in a process called glycogenolysis. The liver both stores and produces sugar… The liver acts as the body’s glucose (or fuel) reservoir, and helps to keep your circulating blood sugar levels and other body fuels steady and constant. The liver both stores and manufactures glucose depending upon the body’s need. The need to store or release glucose is primarily signaled by the hormones insulin and glucagon. During a meal, your liver will store sugar, or glucose, as glycogen for a later time when your body needs it. The high levels of insulin and suppressed levels of glucagon during a meal promote the storage of glucose as glycogen. The liver makes sugar when you need it…. When you’re not eating – especially overnight or between meals, the body has to make its own sugar. The liver supplies sugar or glucose by turning glycogen into glucose in a process called glycogenolysis. The liver also can manufacture necessary sugar or glucose by harvesting amino acids, waste products and fat byproducts. This process is called gluconeogenesis. When your body’s glycogen storage is running low, the body starts to conserve the sugar supplies for the organs that always require sugar. These include: the brain, red blood cells and parts of the kidney. To supplement the limited sugar supply, the liver makes alternative fuels called ketones from fats. This process is called ketogenesis. The hormone signal for ketogenesis to begin is a low level of insulin. Ketones are burned as fuel by muscle and other body organs. And the sugar is saved for the organs that need it. The terms “gluconeogenesis, glycogenolysis and ketogenesis” may seem like compli Continue reading >>

The Liver And Blood Glucose Levels

The Liver And Blood Glucose Levels

Tweet Glucose is the key source of energy for the human body. Supply of this vital nutrient is carried through the bloodstream to many of the body’s cells. The liver produces, stores and releases glucose depending on the body’s need for glucose, a monosaccharide. This is primarily indicated by the hormones insulin - the main regulator of sugar in the blood - and glucagon. In fact, the liver acts as the body’s glucose reservoir and helps to keep your circulating blood sugar levels and other body fuels steady and constant. How the liver regulates blood glucose During absorption and digestion, the carbohydrates in the food you eat are reduced to their simplest form, glucose. Excess glucose is then removed from the blood, with the majority of it being converted into glycogen, the storage form of glucose, by the liver’s hepatic cells via a process called glycogenesis. Glycogenolysis When blood glucose concentration declines, the liver initiates glycogenolysis. The hepatic cells reconvert their glycogen stores into glucose, and continually release them into the blood until levels approach normal range. However, when blood glucose levels fall during a long fast, the body’s glycogen stores dwindle and additional sources of blood sugar are required. To help make up this shortfall, the liver, along with the kidneys, uses amino acids, lactic acid and glycerol to produce glucose. This process is known as gluconeogenesis. The liver may also convert other sugars such as sucrose, fructose, and galactose into glucose if your body’s glucose needs not being met by your diet. Ketones Ketones are alternative fuels that are produced by the liver from fats when sugar is in short supply. When your body’s glycogen storage runs low, the body starts conserving the sugar supplies fo 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 >>

An Overview Of The Pancreas

An Overview Of The Pancreas

Pancreas Essentials The pancreas maintains the body’s blood glucose (sugar) balance. Primary hormones of the pancreas include insulin and glucagon, and both regulate blood glucose. Diabetes is the most common disorder associated with the pancreas. The pancreas is unique in that it’s both an endocrine and exocrine gland. In other words, the pancreas has the dual function of secreting hormones into blood (endocrine) and secreting enzymes through ducts (exocrine). The pancreas belongs to the endocrine and digestive systems—with most of its cells (more than 90%) working on the digestive side. However, the pancreas performs the vital duty of producing hormones—most notably insulin—to maintain the balance of blood glucose (sugar) and salt in the body. Without this balance, your body is susceptible to serious complications, such as diabetes. Anatomy of the Pancreas The pancreas is a 6 inch-long flattened gland that lies deep within the abdomen, between the stomach and the spine. It is connected to the duodenum, which is part of the small intestine. Only about 5% of the pancreas is comprised of endocrine cells. These cells are clustered in groups within the pancreas and look like little islands of cells when examined under a microscope. These groups of pancreatic endocrine cells are known as pancreatic islets or more specifically, islets of Langerhans (named after the scientist who discovered them). Hormones of the Pancreas The production of pancreatic hormones, including insulin, somatostatin, gastrin, and glucagon, play an important role in maintaining sugar and salt balance in our bodies. Gastrin: This hormone aids digestion by stimulating certain cells in the stomach to produce acid. Glucagon: Glucagon helps insulin maintain normal blood glucose by working in the Continue reading >>

Controlling Blood Sugar Levels

Controlling Blood Sugar Levels

Glucose is a sugar needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body. It travels from the pancreas to the liver in the bloodstream. As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system. Blood sugar levels- Higher tier What happens when glucose levels in the blood become too high or too low 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 Diabetes is a disorder in which the blood glucose levels remain too high. There are two main types of diabetes: Type 1, which usually develops during childhood Type 2, which usually develops in later life. The table summarises some differences between Type 1 and Type 2 diabetes. Some differences between Type 1 and Type 2 diabetes Type 1 diabetes Type 2 diabetes Who it mainly affects Children and teenagers. Adults under the age of 40. Adults, normally over the age of 40 (there is a greater risk in those who have poor diets and/or are overweight). How it works The pancreas stops making enough insulin. The body no longer responds to its insulin. How it is controlled Injections of insulin for life and an appropriate diet. Exercise and appropriate diet. When treating Type 1 diabetes, the dosage of in Continue reading >>

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