islets of Langerhans

Examples of islets of Langerhans in the following topics:

• Types of Cells in the Pancreas

  • The islets of Langerhans are the regions of the pancreas that contain many endocrine (i.e., hormone-producing) cells.
  • The lightly-staining clusters of cells are called islets of Langerhans, which produce hormones that underlie the endocrine functions of the pancreas.
  • The islets of Langerhans are the regions of the pancreas that contain many endocrine (i.e., hormone-producing) cells.
  • The islets of Langerhans can influence each other through paracrine and autocrine communication.
  • A porcine islet of Langerhans.

• Overview of Pancreatic Islets

  • Pancreatic islets, or the islets of Langerhans, are regions of the pancreas that contain its endocrine, or, hormone-producing, cells.
  • The endocrine function of the pancreas is involved in maintaining blood glucose levels, and the structures involved are known as the pancreatic islets, or, islets of Langerhans.
  • Alpha cells- the alpha cells produce glucagon, and make up 15–20% of total islet cells.
  • The feedback system of the pancreatic islets is paracrine, and is based on the activation and inhibition of the islet cells by the endocrine hormones produced in the islets.
  • The islets of Langerhans are the regions of the pancreas that contain its endocrine ( hormone-producing) cells.

• Histology of the Pancreas

  • The pancreas serves digestive and endocrine functions, and it is composed of two types of tissue: islets of Langerhans and acini.
  • Lightly-staining clusters of cells are called islets of Langerhans.
  • The part of the pancreas with endocrine function is made up of approximately a million cell clusters called islets of Langerhans.
  • Four main cell types exist in the islets.
  • The islets are a compact collection of endocrine cells arranged in clusters and cords and are crisscrossed by a dense network of capillaries.

• Pancreas

  • The pancreas is an elongated organ that is located between the stomach and the proximal portion of the small intestine .
  • The endocrine cells of the pancreas form clusters called pancreatic islets or the islets of Langerhans .
  • The pancreatic islets contain two primary cell types: alpha cells, which produce the hormone glucagon, and beta cells, which produce the hormone insulin.
  • These hormones are responsible for the regulation of blood glucose levels.
  • The islets of Langerhans are clusters of endocrine cells found in the pancreas; they stain lighter than surrounding cells.

• Pancreas

  • The part of the pancreas with endocrine function is made up of approximately a million cell clusters called islets of Langerhans.
  • Four main cell types exist in the islets.
  • The islets are a compact collection of endocrine cells arranged in clusters and cords and are crisscrossed by a dense network of capillaries.
  • Nourse, the islets are "busily manufacturing their hormone and generally disregarding the pancreatic cells all around them, as though they were located in some completely different part of the body. " The islet of Langerhans plays an imperative role in glucose metabolism and regulation of blood glucose concentration.
  • In humans, the secretory activity of the pancreas is regulated directly via the effect of hormones in the blood on the islets of Langerhans and indirectly through the effect of the autonomic nervous system on the blood flow.

• Interactions of Hormones at Target Cells

  • When conditions exceed the upper limit of homeostasis, specific action, usually the production of a hormone, is triggered.
  • If conditions exceed the lower limits of homeostasis, a different action, usually the production of a second hormone is triggered.
  • Bundles of cells in the pancreas, called the islets of Langerhans, contain two kinds of cells, alpha cells and beta cells.
  • Another example of antagonistic hormones occurs in the maintenance of Ca2+ ion concentration in the blood.
  • Calcitonin (CT) produces the opposite effect by inhibiting the breakdown of bone matrix and decreasing the release of calcium in the blood.

• Insulin Secretion and Regulation of Glucagon

  • In situations of high blood glucose, or hyperglycemia, insulin takes over, stimulating the storage of excess blood glucose in the form of glycogen for later use.
  • The objective of glucagon is to increase the amount of glucose in the blood for use by cells of the body.
  • When there is a lack of glucose in the blood, the islets of langerhans on the pancreas are stimulated to create and release glucagon into the bloodstream.
  • Insulin stops the use of fat as an energy source by inhibiting the release of glucagon .
  • Over 40% of those with Type 2 diabetes require insulin as part of their diabetes management plan.

• Secondary & Tertiary Structure of Large Peptides and Proteins

  • The planarity of peptide bonds.
  • A liter of arterial blood at body temperature can transport over 200 mL of oxygen, whereas the same fluid stripped of its hemoglobin will carry only 2 to 3 mL.
  • Insulin is a peptide hormone composed of 51 amino acids, with a molecular weight of 5808 Da.
  • Insulin is formed in the islets of Langerhans in the pancreas.
  • The molecular structure of insulin varies slightly between species of animals.

• Wood Carving in the Caroline Islands

  • By the 8th or 9th century, islet construction had started, but the distinctive megalithic architecture was probably not begun until the 12th or early 13th century.
  • Today Nan Madol forms an archaeological district covering more than 18 km² and includes the stone architecture built up on a coral reef flat along the shore of Temwen Island, several other artificial islets, and the adjacent Pohnpei main island coastline.
  • The site core with its stone walls encloses an area approximately 1.5 km long by 0.5 km wide and contains nearly 100 artificial islets—stone and coral fill platforms—bordered by tidal canals.
  • Many islets were once occupied by the dwellings of priests, while some islets served a special purpose such as food preparation, canoe construction on Dapahu, or coconut oil preparation on Peinering.
  • High walls surrounding tombs are located on Peinkitel, Karian, and Lemenkou, but the most prominent is the royal mortuary islet of Nandauwas, where walls 18–25 feet high surround a central tomb enclosure within the main courtyard.

• Pancreatic Islet Disorders: Diabetes and Hyperinsulinism

  • Hyperinsulinism refers to an above-normal level of insulin in the blood of a person or animal.
  • This refers to an above-normal level of insulin in the blood of a person or animal.
  • It can produce a variety of symptoms and effects but the principal problems arise from an inadequate supply of glucose to the brain, resulting in impairment of function (neuroglycopenia).
  • The most common forms of hypoglycemia occur as a complication of treatment of diabetes mellitus with insulin or oral medications.
  • Recurrent hypoglycemia may be prevented by reversing or removing the underlying cause, by increasing the frequency of meals, with medications like diazoxide, octreotide, or glucocorticoids, or by surgical removal of much of the pancreas.