Diabetes Management Quiz

Endocrinology 3 - Pancreas, Diabetes & Pineal Gland

• The pancreas is a multifunctional organ involved in the digestive and endocrine systems.
• It's an elongated gland, roughly the size of a hand.
• Located in the upper left quadrant of the abdominal cavity.
• Extends from the duodenum curve to the spleen.
• The pancreas is both an exocrine and endocrine gland.

Pancreatic Islets (Islets of Langerhans)

• Contain hormone-producing cells scattered throughout the pancreas.
• Pancreatic hormones are released directly into the bloodstream.
• Circulate throughout the body.

Types of Pancreatic Islet Cells

• Alpha (α) cells (17%): Secrete glucagon.
• Beta (β) cells (70%): Secrete insulin. The most numerous.
• Delta (δ) cells (7%): Secrete somatostatin (GHRIH).
• F cells: Secrete pancreatic polypeptide.

Pancreas: Exocrine Function

• Acinar cells secrete digestive enzymes into pancreatic ducts.

Pineal Gland

• A small brain structure near the hypothalamus.
• Approximately 10mm in length.
• Surrounded by a capsule.
• Primarily produces the hormone melatonin at night.
• Often atrophies after puberty and may calcify later in life.
• Melatonin secretion is regulated by daylight and darkness.

Insulin (Polypeptide)

• Secretion stimulated by:
  • Digestion and absorption of food (carbohydrates and proteins).
  • Elevated blood glucose levels.
  • Parasympathetic stimulation (acetylcholine).
  • Elevated blood amino acids and fatty acids.
  • Some hormones like GIP, hGH, and ACTH.
• Counteracted by, or inhibited by:
  • Sympathetic stimulation (epinephrine).
  • Glucagon.
  • Some hormones like somatostatin (GHRIH).
• Insulin lowers blood glucose by:
  • Accelerating glucose transport into cells.
  • Converting glucose to glycogen (glycogenesis).
  • Decreasing glycogen breakdown (glycogenolysis).
  • Increasing lipogenesis (fat synthesis).

Glucagon

• Secretion stimulated by:
  • Low blood glucose levels.
  • Physiological stress (e.g. exercise).
  • Elevated blood amino acid levels (especially following a protein-rich meal).
• Glucagon increases blood glucose levels by:
  • Stimulating glycogenolysis (conversion of glycogen to glucose in the liver and muscles).
  • Increasing gluconeogenesis (forming glucose from non-carbohydrate sources).

Somatostatin

• Produced by pancreas delta cells.
• Similar to growth hormone-inhibiting hormone (GHRIH).
• Acts locally to inhibit insulin and glucagon secretion.
• Inhibits absorption of nutrients from the GI tract.
• Inhibited by pancreatic polypeptide.

Blood Glucose Regulation

• Insulin and glucagon regulate blood glucose levels via a negative feedback mechanism.

Diabetes Mellitus (DM)

• The most common endocrine disorder.

• Results from:

  • Insulin deficiency or absence.
  • Resistance to insulin action.

• Symptoms can include:

  • Frequent urination.
  • Excessive thirst.
  • Increased hunger.
  • Blurred vision.
  • Fatigue and weakness.

• Type 1 DM:

  • Characterized by autoimmune destruction of the beta cells in the pancreas, leading to little/no insulin production.
  • Typically develops in childhood.

• Type 2 DM:

  • Characterized by insulin resistance (cells don't respond effectively to insulin) and often by insufficient insulin production.
  • Typically develops in adulthood, but becoming more common in childhood.

Acute Complications of DM

• Diabetic Microangiopathy:
  • Damages small blood vessels.
  • Can result in peripheral vascular disease, gangrene, diabetic retinopathy (vision impairment), diabetic nephropathy (kidney damage), and peripheral neuropathy (nerve damage).
• Diabetes Infection:
  • Related to difficulty in fighting off infection (impaired immune response).
  • Can result in boils, carbuncles, vaginal candidiasis, and pyelonephritis.
• Diabetic Foot:
  • A serious complication related to poor blood supply and nerve damage in the lower extremities.
  • Often leads to ulcers, gangrene, and amputation.
• Renal Failure:
  • Due to diabetic nephropathy (kidney damage).
• Visual Impairment and Blindness:
  • Diabetic retinopathy (damage to the blood vessels in the retina).
  • Cataracts (clouding of the lens).

Treatments for Diabetes

• Type 1 DM:
  • Insulin replacement.
• Type 2 DM:
  • Diet and exercise.
  • Medications to improve insulin sensitivity.
  • Sometimes require insulin eventually.

Glucose Tolerance Test

• A test to diagnose diabetes.
• Measures blood glucose levels after consuming a glucose solution.
• Elevated and sustained blood glucose levels above a specific threshold indicate diabetes.