Diabetes is the most common disorder associated with :

Question

UnlockIAS · Accepted Answer

Correct — D, Pancreas. Diabetes mellitus is a disorder of blood-glucose control, and blood glucose is held down by exactly one hormone — insulin — which is made in exactly one place in the body: the beta cells of the islets of Langerhans, the endocrine tissue scattered through the pancreas. Every form of the disease is therefore a failure at that pancreatic step. In Type 1 diabetes the immune system destroys the beta cells, so insulin production collapses altogether and the patient depends on injected insulin. In Type 2 diabetes, which accounts for the large majority of cases, the tissues become resistant to insulin and the beta cells, after years of over-secreting to compensate, progressively fail to keep up — a relative deficiency rather than an absolute one. In both, glucose that should have been driven into cells stays in the blood, and chronic hyperglycaemia is what defines the disease. The pancreas is also the only organ among the four options with any glucose-regulating hormone of its own: alongside insulin from the beta cells, its alpha cells make glucagon, which raises blood glucose, and the delta cells make somatostatin. The other three organs listed are all touched by diabetes in one way or another, but none of them produces insulin, and so none of them is where the disorder originates.

Why the other options are wrong — (a) The most historically tempting wrong answer, because the kidney is where diabetes was traditionally detected — once plasma glucose rises past the renal threshold of roughly 180 mg/dL the tubules can no longer reabsorb it all and sugar spills into the urine, which is the glycosuria that gave the disease its name of 'sweet urine'. The kidney is also the organ most famously damaged by long-standing diabetes, diabetic nephropathy being a leading cause of end-stage renal disease. But in both roles the kidney is a victim and a window, not the source. Note also that diabetes insipidus, despite its name, is an entirely different disease of vasopressin (ADH) and water handling, with no rise in blood sugar at all.  (b) The gall bladder is a storage sac. It concentrates and stores the bile that the liver makes and releases it into the duodenum to emulsify fats; it secretes no hormone and plays no part in glucose regulation. Its own characteristic disorders are gallstones (cholelithiasis) and inflammation (cholecystitis). It is placed in the option set only because it sits beside the pancreas and liver in the upper abdomen and shares the biliary plumbing with them.  (c) The most defensible wrong option, and worth understanding rather than merely eliminating. The liver is the body's glucose warehouse: it stores glucose as glycogen (glycogenesis), releases it again on demand (glycogenolysis), and manufactures fresh glucose from non-carbohydrate sources (gluconeogenesis). It is a principal target organ of insulin, and in diabetes an insulin-resistant liver pours out glucose it should be holding back. But the liver executes instructions; it does not issue them. It makes no insulin, and a disease of insulin is a disease of the organ that makes insulin.

Concept: The pancreas is a heterocrine, or mixed, gland — it works as both an exocrine and an endocrine organ. Its exocrine bulk, the acinar tissue, makes pancreatic juice (amylase, lipase, nucleases and the protein-digesting zymogens trypsinogen and chymotrypsinogen, with bicarbonate from the duct cells) and delivers it through the pancreatic duct into the duodenum. Embedded in that bulk, making up only a small fraction of the organ, are about a million islets of Langerhans, the endocrine part, which secrete straight into the bloodstream: beta cells make insulin, alpha cells make glucagon, delta cells make somatostatin. Insulin and glucagon are antagonists, and the balance between them is what holds blood glucose within a narrow range.

State PCS 2024 Q69 — Science & Technology PYQ with Answer

State PCS 2024 Q69 — Science & Technology PYQ with Answer