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Normal Anatomy Of Diabetes Mellitus

114 17.9 The Endocrine Pancreas

114 17.9 The Endocrine Pancreas

Learning Objectives By the end of this section, you will be able to: Describe the location and structure of the pancreas, and the morphology and function of the pancreatic islets Compare and contrast the functions of insulin and glucagon The pancreas is a long, slender organ, most of which is located posterior to the bottom half of the stomach (Figure 1). Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas has an endocrine function. Its pancreatic islets—clusters of cells formerly known as the islets of Langerhans—secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide (PP). Figure 1. Pancreas. The pancreatic exocrine function involves the acinar cells secreting digestive enzymes that are transported into the small intestine by the pancreatic duct. Its endocrine function involves the secretion of insulin (produced by beta cells) and glucagon (produced by alpha cells) within the pancreatic islets. These two hormones regulate the rate of glucose metabolism in the body. The micrograph reveals pancreatic islets. LM × 760. (Micrograph provided by the Regents of University of Michigan Medical School © 2012) View the University of Michigan WebScope at to explore the tissue sample in greater detail. View the University of Michigan WebScope at to explore the tissue sample in greater detail. Cells and Secretions of the Pancreatic Islets The pancreatic islets each contain four varieties of cells: The alpha cell produces the hormone glucagon and makes up approximately 20 percent of each islet. Glucagon plays an important role in blood glucose regulation; low blood glucose levels stimulate its release. The beta cell produces the hormone insulin and makes up approximately 75 percent of each islet. Elevated Continue reading >>

Diabetes: Type 1 And Type 2

Diabetes: Type 1 And Type 2

An important example of negative feedback is the control of blood sugar. After a meal, the small intestine absorbs glucose from digested food. Blood glucose levels rise. Increased blood glucose levels stimulate beta cells in the pancreas to produce insulin. Insulin triggers liver, muscle, and fat tissue cells to absorb glucose, where it is stored. As glucose is absorbed, blood glucose levels fall. Once glucose levels drop below a threshold, there is no longer a sufficient stimulus for insulin release, and the beta cells stop releasing insulin. Due to synchronization of insulin release among the beta cells, basal insulin concentration oscillates in the blood following a meal. The oscillations are clinically important, since they are believed to help maintain sensitivity of insulin receptors in target cells. This loss of sensitivity is the basis for insulin resistance. Thus, failure of the negative feedback mechanism can result in high blood glucose levels, which have a variety of negative health effects. Let’s take a closer look at diabetes. In particular, we will discuss diabetes type 1 and type 2. Diabetes can be caused by too little insulin, resistance to insulin, or both. Type 1 Diabetes occurs when the pancreatic beta cells are destroyed by an immune-mediated process. Because the pancreatic beta cells sense plasma glucose levels and respond by releasing insulin, individuals with type 1 diabetes have a complete lack of insulin. In this disease, daily injections of insulin are needed. Also affected are those who lose their pancreas. Once the pancreas has been removed (because of cancer, for example), diabetes type 1 is always present. Type 2 Diabetes is far more common than type 1. It makes up most of diabetes cases. It usually occurs in adulthood, but young people Continue reading >>

Pathophysiology Of Type 2 Diabetes.

Pathophysiology Of Type 2 Diabetes.

Abstract Type 2 diabetes mellitus is a heterogeneous syndrome characterized by abnormalities in carbohydrate and fat metabolism. The causes of type 2 diabetes are multi-factorial and include both genetic and environmental elements that affect beta-cell function and tissue (muscle, liver, adipose tissue, pancreas) insulin sensitivity. Although there is considerable debate as to the relative contributions of beta-cell dysfunction and reduced insulin sensitivity to the pathogenesis of diabetes, it is generally agreed that both these factors play important roles. However, the mechanisms controlling the interplay of these two impairments are unclear. A number of factors have been suggested as possibly linking insulin resistance and beta-cell dysfunction in the pathogenesis of type 2 diabetes. A majority of individuals suffering from type 2 diabetes are obese, with central visceral adiposity. Therefore, the adipose tissue should play a crucial role in the pathogenesis of type 2 diabetes. Although the predominant paradigm used to explain this link is the portal/visceral hypothesis giving a key role in elevated non-esterified fatty acid concentrations, two new emerging paradigms are the ectopic fat storage syndrome (deposition of triglycerides in muscle, liver and pancreatic cells) and the adipose tissue as endocrine organ hypothesis (secretion of various adipocytokins, i.e. leptin, TNF-alpha, resistin, adiponectin, implicated in insulin resistance and possibly beta-cell dysfunction). These two paradigms constitute the framework for the study of the interplay between insulin resistance and beta-cell dysfunction in type 2 diabetes as well as between our obesogenic environment and diabetes risk in the next decade. Continue reading >>

Diabetes Pathophysiology

Diabetes Pathophysiology

Diabetes occurs when there is a dis-balance between the demand and production of the hormone insulin. Control of blood sugar When food is taken, it is broken down into smaller components. Sugars and carbohydrates are thus broken down into glucose for the body to utilize them as an energy source. The liver is also able to manufacture glucose. In normal persons the hormone insulin, which is made by the beta cells of the pancreas, regulates how much glucose is in the blood. When there is excess of glucose in blood, insulin stimulates cells to absorb enough glucose from the blood for the energy that they need. Insulin also stimulates the liver to absorb and store any excess glucose that is in the blood. Insulin release is triggered after a meal when there is a rise in blood glucose. When blood glucose levels fall, during exercise for example, insulin levels fall too. High insulin will promote glucose uptake, glycolysis (break down of glucose), and glycogenesis (formation of storage form of glucose called glycogen), as well as uptake and synthesis of amino acids, proteins, and fat. Low insulin will promote gluconeogenesis (breakdown of various substrates to release glucose), glycogenolysis (breakdown of glycogen to release gluose), lipolysis (breakdown of lipids to release glucose), and proteolysis (breakdown of proteins to release glucose). Insulin acts via insulin receptors. Liver Adipose or fat Tissue Muscle High insulin Glycolysis Glycogenesis Triglyceride synthesis Amino acid uptake Protein synthesis Low insulin Gluconeogenesis Glycogenolysis Lipolysis Proteolysis Normal Responses to Eating and Fasting In a fed state: there is increased insulin secretion, causing glycolysis, glycogen storage, fatty acid synthesis/storage, and protein synthesis. After an overnight fast: Continue reading >>

Physiologic Response To Hypoglycemia In Normal Subjects And Patients With Diabetes Mellitus

Physiologic Response To Hypoglycemia In Normal Subjects And Patients With Diabetes Mellitus

INTRODUCTION The brain relies almost exclusively on glucose as a fuel, but cannot synthesize or store much of it. As a result, adequate uptake of glucose from the plasma is essential for normal brain function and survival. Given the survival value of maintenance of the plasma glucose concentration, it is not surprising that very effective physiological and behavioral mechanisms that normally prevent or rapidly correct hypoglycemia have evolved. As a result, hypoglycemia is an uncommon clinical event except in patients who use drugs that lower glucose levels, particularly those with diabetes who use insulin, a sulfonylurea, or a glinide. In addition to being at increased risk for hypoglycemia, diabetic patients treated with insulin often have impaired neurohumoral responses to and few early symptoms of low blood glucose concentrations [1-4]. This topic card will review glucose metabolism and the response to hypoglycemia in normal subjects and in patients with diabetes. The therapeutic approach to hypoglycemia in diabetic patients is discussed separately. (See "Management of hypoglycemia during treatment of diabetes mellitus".) REGULATION OF GLUCOSE HOMEOSTASIS In normal subjects, the extracellular supply of glucose is carefully regulated primarily by insulin and glucagon (figure 1) [1-4]. As plasma glucose concentrations rise after a meal, glucose enters the pancreatic beta-cells. In the cells, the enzyme glucokinase, which phosphorylates glucose to glucose-6-phosphate, may act as the glucose sensor, initiating a sequence of events leading to entry of calcium and insulin release. (See "Pancreatic beta cell function".) Insulin acts to restore normoglycemia primarily through the following two mechanisms: It decreases hepatic glucose production by diminishing both glycogeno Continue reading >>

Diabetes: Mechanism, Pathophysiology And Management-a Review

Diabetes: Mechanism, Pathophysiology And Management-a Review

Anees A Siddiqui1*, Shadab A Siddiqui2, Suhail Ahmad, Seemi Siddiqui3, Iftikhar Ahsan1, Kapendra Sahu1 Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Jamia Hamdard (Hamdard University), Hamdard Nagar, New Delhi (INDIA)-110062. School of Pharmacy, KIET, Ghaziabad U.P. SGC college of Pharmacy, Baghpat(UP) Corresponding Author:Anees A Siddiqui E-mail: [email protected] Received: 20 February 2011 Accepted: 02 May 2011 Citation: Anees A Siddiqui, Shadab A Siddiqui, Suhail Ahmad, Seemi Siddiqui, Iftikhar Ahsan, Kapendra Sahu “Diabetes: Mechanism, Pathophysiology and Management-A Review” Int. J. Drug Dev. & Res., April-June 2013, 5(2): 1-23. Copyright: © 2013 IJDDR, Anees A Siddiqui et al. This is an open access paper distributed under the copyright agreement with Serials Publication, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Related article at Pubmed, Scholar Google Visit for more related articles at International Journal of Drug Development and Research The prevalence of diabetes is rapidly rising all over the globe at an alarming rate. Over the last three decades, the status of diabetes has been changed, earlier it was considered as a mild disorder of the elderly people. Now it becomes a major cause of morbidity and mortality affecting the youth and middle aged people. According to the Diabetes Atlas 2006 published by the International Diabetes Federation, the number of people with diabetes in India currently around 40.9 million is expected to rise to 69.9 million by 2025 unless urgent preventive steps are taken. The main force of the epidemic of diabetes is the rapid epidemiological transition associated with changes in dietary patterns and decreased physical activity a Continue reading >>

Anatomy Of The Pancreas

Anatomy Of The Pancreas

The pancreas is an organ that stretches partway across the abdomen, just below the stomach. Because its main functions are to aid digestion and produce hormones that control blood glucose levels, the pancreas is a focal point for understanding diabetes. In addition to secreting certain enzymes that help you properly digest food, the pancreas manufactures hormones that regulate blood glucose - the fuel that provides the body's cells with energy. Scattered throughout the pancreas are tiny nests of cells known as islets of Langerhans; the majority of the cells are beta cells that produce and store the hormone insulin until needed. Also located in the islets are alpha cells, which make and store glucagon, a hormone that counteracts the effects of insulin. After a meal, carbohydrates in foods are converted into glucose in the intestine and liver and enter the bloodstream. Beta cells sense the rising blood glucose levels and secrete insulin into the blood. Once in the bloodstream, insulin helps glucose enter the body's cells, where it can be "burned" by the liver and muscles for energy. Liver and muscles can also convert glucose to glycogen, a type of reserve form of energy that is stored there for future needs.When the body is working as it should, blood glucose levels quickly return to normal, and insulin secretion decreases. A drop in blood glucose levels - for example, when one hasn't eaten for several hours - stimulates an opposite effect: alpha cells secrete glucagon into the blood, which converts stored glycogen back into energy-producing glucose. Normally, the secretion of these hormones by the pancreas is perfectly balanced: Beta and alpha cells continuously monitor blood glucose levels and release insulin or glucagon as needed. In diabetes, this balance is thrown of Continue reading >>

Pancreas: Anatomy And Functions

Pancreas: Anatomy And Functions

Anatomy of the pancreas The pancreas is an elongated, tapered organ located across the back of the abdomen, behind the stomach. The right side of the organ, called the head, is the widest part of the organ. It lies in the curve of the duodenum, the first section of the small intestine. The tapered left side extends slightly upward, called the body of the pancreas, and ends near the spleen, called the tail. The pancreas is made up of 2 types of glands: Exocrine. The exocrine gland secretes digestive enzymes. These enzymes are secreted into a network of ducts that join the main pancreatic duct. It runs the length of the pancreas. Endocrine. The endocrine gland consists of the islets of Langerhans and secretes hormones into the bloodstream. Functions of the pancreas The pancreas has digestive and hormonal functions: The enzymes secreted by the exocrine gland in the pancreas help break down carbohydrates, fats, proteins, and acids in the duodenum. These enzymes travel down the pancreatic duct into the bile duct in an inactive form. When they enter the duodenum, they are activated. The exocrine tissue also secretes a bicarbonate to neutralize stomach acid in the duodenum. The main hormones secreted by the endocrine gland in the pancreas are insulin and glucagon. They regulate the level of glucose in the blood, and somatostatin, which prevents the release of the other 2 hormones. 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 >>

Type 2 Diabetes Mellitus

Type 2 Diabetes Mellitus

Author: Romesh Khardori, MD, PhD, FACP; Chief Editor: George T Griffing, MD more... Type 2 diabetes mellitus consists of an array of dysfunctions characterized by hyperglycemia and resulting from the combination of resistance to insulin action, inadequate insulin secretion, and excessive or inappropriate glucagon secretion. See the image below. Simplified scheme for the pathophysiology of type 2 diabetes mellitus. See Clinical Findings in Diabetes Mellitus , a Critical Images slideshow, to help identify various cutaneous, ophthalmologic, vascular, and neurologic manifestations of DM. Many patients with type 2 diabetes are asymptomatic. Clinical manifestations include the following: Classic symptoms: Polyuria, polydipsia, polyphagia, and weight loss Diagnostic criteria by the American Diabetes Association (ADA) include the following [ 1 ] : A fasting plasma glucose (FPG) level of 126 mg/dL (7.0 mmol/L) or higher, or A 2-hour plasma glucose level of 200 mg/dL (11.1 mmol/L) or higher during a 75-g oral glucose tolerance test (OGTT), or A random plasma glucose of 200 mg/dL (11.1 mmol/L) or higher in a patient with classic symptoms of hyperglycemia or hyperglycemic crisis Whether a hemoglobin A1c (HbA1c) level of 6.5% or higher should be a primary diagnostic criterion or an optional criterion remains a point of controversy. Indications for diabetes screening in asymptomatic adults includes the following [ 2 , 3 ] : Overweight and 1 or more other risk factors for diabetes (eg, first-degree relative with diabetes, BP >140/90 mm Hg, and HDL < 35 mg/dL and/or triglyceride level >250 mg/dL) ADA recommends screening at age 45 years in the absence of the above criteria Microvascular (ie, eye and kidney disease) risk reduction through control of glycemia and blood pressure Macrovas Continue reading >>

Type 2 Diabetes

Type 2 Diabetes

Type 2 diabetes is a progressive condition in which the body becomes resistant to the normal effects of insulin and/or gradually loses the capacity to produce enough insulin in the pancreas. We do not know what causes type 2 diabetes. Type 2 diabetes is associated with modifiable lifestyle risk factors. Type 2 diabetes also has strong genetic and family related risk factors. Type 2 diabetes: Is diagnosed when the pancreas does not produce enough insulin (reduced insulin production) and/or the insulin does not work effectively and/or the cells of the body do not respond to insulin effectively (known as insulin resistance) Represents 85–90 per cent of all cases of diabetes Usually develops in adults over the age of 45 years but is increasingly occurring in younger age groups including children, adolescents and young adults Is more likely in people with a family history of type 2 diabetes or from particular ethnic backgrounds For some the first sign may be a complication of diabetes such as a heart attack, vision problems or a foot ulcer Is managed with a combination of regular physical activity, healthy eating and weight reduction. As type 2 diabetes is often progressive, most people will need oral medications and/or insulin injections in addition to lifestyle changes over time. Type 2 diabetes develops over a long period of time (years). During this period of time insulin resistance starts, this is where the insulin is increasingly ineffective at managing the blood glucose levels. As a result of this insulin resistance, the pancreas responds by producing greater and greater amounts of insulin, to try and achieve some degree of management of the blood glucose levels. As insulin overproduction occurs over a very long period of time, the insulin producing cells in the pan Continue reading >>

Diabetes Mellitus

Diabetes Mellitus

"Diabetes" redirects here. For other uses, see Diabetes (disambiguation). Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period.[7] Symptoms of high blood sugar include frequent urination, increased thirst, and increased hunger.[2] If left untreated, diabetes can cause many complications.[2] Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death.[3] Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, and damage to the eyes.[2] Diabetes is due to either the pancreas not producing enough insulin or the cells of the body not responding properly to the insulin produced.[8] There are three main types of diabetes mellitus:[2] Type 1 DM results from the pancreas's failure to produce enough insulin.[2] This form was previously referred to as "insulin-dependent diabetes mellitus" (IDDM) or "juvenile diabetes".[2] The cause is unknown.[2] Type 2 DM begins with insulin resistance, a condition in which cells fail to respond to insulin properly.[2] As the disease progresses a lack of insulin may also develop.[9] This form was previously referred to as "non insulin-dependent diabetes mellitus" (NIDDM) or "adult-onset diabetes".[2] The most common cause is excessive body weight and insufficient exercise.[2] Gestational diabetes is the third main form, and occurs when pregnant women without a previous history of diabetes develop high blood sugar levels.[2] Prevention and treatment involve maintaining a healthy diet, regular physical exercise, a normal body weight, and avoiding use of tobacco.[2] Control of blood pressure and maintaining proper foot care are important for people with t Continue reading >>

Anatomy And Physiology Of Diabetes | Global Events |usa| Europe | Middle East | Asia Pacific

Anatomy And Physiology Of Diabetes | Global Events |usa| Europe | Middle East | Asia Pacific

Pathophysiologic alteration is a change in function as distinguished from a structural defect. Diabetes occurs when there is a dis-balance between the demand and production of the hormone insulin. Pathophysiology of type 1 diabetes is that in this condition the immune system attacks and destroys the insulin producing beta cells of the pancreas. There is beta cell deficiency leading to complete insulin deficiency. Whereas in diabetes type 2 there is relative deficiency of insulin and not an absolute deficiency. This means that the body is unable to produce adequate insulin to meet the needs. There is Beta cell deficiency coupled with peripheral insulin resistance. Third type of diabetes is gestational diabetes. It is caused when there are excessive counter-insulin hormones of pregnancy. This leads to a state of insulin resistance and high blood sugar in the mother. There may be defective insulin receptors. Understanding diabetes, requires an effective grasp on the body parts involved. When a patient is diagnosed with this disease, what exactly is happening.The pancreas is an organ that stretches partway across the abdomen, just below the stomach. Because its main functions are to aid digestion and produce hormones that control blood glucose levels, the pancreas is a focal point for understanding diabetes. The Role of Incretins in Insulin Secretion Related Conference of Anatomy and Physiology of Diabetes Continue reading >>

Diabetes Mellitus Type 1

Diabetes Mellitus Type 1

Diabetes mellitus type 1 (also known as type 1 diabetes) is a form of diabetes mellitus in which not enough insulin is produced.[4] This results in high blood sugar levels in the body.[1] The classical symptoms are frequent urination, increased thirst, increased hunger, and weight loss.[4] Additional symptoms may include blurry vision, feeling tired, and poor healing.[2] Symptoms typically develop over a short period of time.[1] The cause of type 1 diabetes is unknown.[4] However, it is believed to involve a combination of genetic and environmental factors.[1] Risk factors include having a family member with the condition.[5] The underlying mechanism involves an autoimmune destruction of the insulin-producing beta cells in the pancreas.[2] Diabetes is diagnosed by testing the level of sugar or A1C in the blood.[5][7] Type 1 diabetes can be distinguished from type 2 by testing for the presence of autoantibodies.[5] There is no known way to prevent type 1 diabetes.[4] Treatment with insulin is required for survival.[1] Insulin therapy is usually given by injection just under the skin but can also be delivered by an insulin pump.[9] A diabetic diet and exercise are an important part of management.[2] Untreated, diabetes can cause many complications.[4] Complications of relatively rapid onset include diabetic ketoacidosis and nonketotic hyperosmolar coma.[5] Long-term complications include heart disease, stroke, kidney failure, foot ulcers and damage to the eyes.[4] Furthermore, complications may arise from low blood sugar caused by excessive dosing of insulin.[5] Type 1 diabetes makes up an estimated 5–10% of all diabetes cases.[8] The number of people affected globally is unknown, although it is estimated that about 80,000 children develop the disease each year.[5] With Continue reading >>

Pathophysiology And Treatment Of Type 2 Diabetes: Perspectives On The Past, Present And Future

Pathophysiology And Treatment Of Type 2 Diabetes: Perspectives On The Past, Present And Future

Go to: Normal regulation of glucose metabolism is determined by a feedback loop involving the islet β-cell and insulin-sensitive tissues in which tissue sensitivity to insulin determines the magnitude of the β-cell response. When insulin resistance is present, the β-cell maintains normal glucose tolerance by increasing insulin output. It is only when the β-cell is incapable of releasing sufficient insulin in the presence of insulin resistance that glucose levels rise. While β-cell dysfunction has a clear genetic component, environmental changes play a vital role. Modern approaches have also informed regarding the importance of hexoses, amino acids and fatty acids in determining insulin resistance and β-cell dysfunction as well as the potential role of alterations in the microbiome. A number of new treatment approaches have been developed, but more effective therapies that slow the progressive loss of β-cell function are needed. Recent clinical trials have provided important information regarding approaches to prevent and treat type 2 diabetes as well as some of the adverse effects of these interventions. However, additional long-term studies of medications and bariatric surgery are required in order to identify novel approaches to prevention and treatment, thereby reducing the deleterious impact of type 2 diabetes. Keywords: type 2 diabetes, impaired glucose tolerance, impaired fasting glucose, pathophysiology, β cell, insulin secretion, insulin resistance, α-cell, glucagon secretion, genetics, environment, inflammation, microbiome, treatment, medications, prevention, clinical trials, bariatric surgery Go to: Type 2 Diabetes: The Epidemic of Our Time The worldwide explosion of obesity has resulted in an ever-increasing prevalence of type 2 diabetes, a non-commu Continue reading >>

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