blood sugar regulation

Examples of blood sugar regulation in the following topics:

• Pancreas

  • The pancreas produces digestive enzymes and hormones, which are important in blood sugar regulation and other body functions.
  • As an endocrine gland, the pancreas produces several important hormones,such as insulin and glucagon, which are secreted into the bloodstream to regulate blood sugar levels, along with other activities throughout the body.
  • These hormones are responsible for the regulation of blood glucose levels.
  • As blood glucose levels decline, alpha cells release glucagon to raise the blood glucose levels by increasing rates of glycogen breakdown and glucose release by the liver.
  • Describe the hormones produced by the pancreas and the functions they regulate

• Disease as Homeostatic Imbalance

  • This leads to high blood pressure and enlargement of the heart, which eventually becomes too stiff to pump blood effectively, resulting in heart failure.
  • Because this ultimately lowers blood glucose levels, insulin is secreted to prevent hyperglycemia (high blood sugar levels).
  • Another hormone called glucagon performs the opposite function of insulin, causing cells to convert glycogen to glucose and stimulating new glucose production (gluconeogenesis) to raise blood sugar levels.
  • Negative feedback between insulin and glucagon levels controls blood sugar homeostasis.
  • With diabetes, blood glucose is increased by normal glucagon activity, but the lack of or resistance to insulin means that blood sugar levels are unable to return to normal.

• Overview of Endocrine Glands

  • Endocrine glands are those glands which have no duct and release their secretions directly into the intercellular fluid or into the blood.
  • The thyroid also produces and releases the hormone calcitonin (thyrocalcitonin) which contributes to the regulation of blood calcium levels.
  • One of its most important functions is to regulate the body's calcium and phosphorus levels.
  • The pancreas is a very important organ in the digestive and the circulatory systems because it helps to maintain our blood sugar levels.
  • It has another, very different function in that it forms insulin, glucagon, and other hormones that are sent into the bloodstream to regulate blood sugar levels and other activities throughout the body.

• Insulin Secretion and Regulation of Glucagon

  • In doing so, glucagon plays a key role in regulating blood glucose levels, providing the fuel necessary for our cells to function even when our bodies are experiencing a low sugar or starved state.
  • Another very important function of glucagon is its stimulation of glycogen breakdown which leads to increased blood sugar levels.
  • Insulin is a peptide hormone , produced by beta cells of the pancreas, and is central to regulating carbohydrate and fat metabolism in the body.
  • 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.
  • Summarize the relationship between insulin secretion and glucagon regulation in blood glucose homeostasis

• The Endocrine System and Hunger

  • Ghrelin is released if blood sugar levels get low, a condition that can result from going long periods without eating.
  • The long-term regulation of hunger prevents energy shortfalls and is concerned with the regulation of body fat.
  • Blood levels of glucose, amino acids, and fatty acids provide a constant flow of information to the brain that may be linked to regulating hunger and energy intake.
  • They inhibit hunger by raising blood glucose levels, elevating blood levels of amino acids, and affecting blood concentrations of fatty acids.
  • When blood sugar levels fall, the hypothalamus is stimulated.

• Hormonal Regulation of Metabolism

  • The levels of glucose in the blood are regulated by the hormones insulin and glucagon from the pancreas, and T3 and T4 from the thyroid.
  • Additional regulation is mediated by the thyroid hormones.
  • These actions mediated by insulin cause blood glucose concentrations to fall, called a hypoglycemic, or "low sugar" effect, which inhibits further insulin release from beta cells through a negative feedback loop.
  • This prevents glucose from being absorbed by cells, causing high levels of blood glucose, or hyperglycemia (high sugar).
  • Oversecretion of insulin can cause hypoglycemia, low blood glucose levels.

• Large-Scale Fermentations

  • The sugars which are most often used include glucose, fructose, and sucrose.
  • Specifically, in wine-making, the yeast will convert the sugars present in the grapes.
  • In beer and additional alcohol such as vodka or whiskey, the yeast will convert the sugars produced as a result of the conversion of grain starches to sugar by amylase .
  • The major source of sugar utilized for ethanol production in the US is currently corn; however, crops such as sugarcane or sugar beets can be used as well.
  • Insulin, produced by the pancreas, serves as a central regulator of carbohydrate and fat metabolism and is responsible for the regulation of glucose levels in the blood.

• Homeostatic Process

  • The varied processes by which the body regulates its internal environment are collectively referred to as homeostasis.
  • Adjustment of physiological systems within the body is called homeostatic regulation, which involves three parts or mechanisms: (1) the receptor, (2) the control center, and (3) the effector.
  • For example, during body temperature regulation, temperature receptors in the skin communicate information to the brain (the control center) which signals the effectors: blood vessels and sweat glands in the skin.
  • If the blood's glucose rises after a meal, adjustments are made to lower the blood glucose level by moving the nutrient into tissues in the command center that require it, or to store it for later use.
  • An example of how homeostasis is achieved by controlling blood sugar levels after a meal.

• Blood Flow in the Skin

  • Blood flow to the skin provides nutrition to skin and regulates body heat through the constriction and dilation of blood vessels.
  • These muscles are under the control of the sympathetic nervous system and provide an efficient means of thermo-regulation through vasoconstriction and vasodilation.
  • When vasoconstricted blood flow through the skin is reduced and so less core heat is lost.
  • With restricted blood flow the skin appears paler.
  • With increased blood flow the skin appears red.

• Overview of Urine Formation

  • The primary function of the renal system is to regulate blood volume and plasma osmolarity, and waste removal via urine is essentially a convenient way in which the body performs many functions using one process.
  • During filtration, blood enters the afferent arteriole and flows into the glomerulus where filterable blood components such as water and nitrogenous waste will move towards the inside of the glomerulus, and nonfilterable components such as cells and serum albumins will exit via the efferent arteriole.
  • Normally, about 20% of the total blood pumped by the heart each minute will enter the kidneys to undergo filtration; this is called the filtration fraction.
  • The remaining 80% of the blood flows through the rest of the body to facilitate tissue perfusion and gas exchange.
  • Red blood cells and sugar are not normally found in urine but may indicate glomerulus injury and diabetes mellitus respectively.