Endocrine Pancreas and Type 1 Diabetes

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Questions and Answers

What factor is commonly linked to the development of Type 2 diabetes?

Increased insulin receptor numbers

High levels of physical activity

Obesity (correct)

Low genetic predisposition

What is the primary indicator for diagnosing diabetes?

Serum insulin levels

Fasting glucose level over 126 mg/dL (correct)

HbA1c level below 5%

Random glucose level below 200 mg/dL

Which long-term consequence is NOT associated with nonenzymatic glycosylation in diabetes?

Hyaline arteriolosclerosis

Glomerulosclerosis

Hyperosmolar non-ketotic coma (correct)

Atherosclerosis

Which of the following describes a significant change during the progression of Type 2 diabetes?

Insulin deficiency due to beta cell exhaustion Signup and view all the answers

What is a clinical manifestation of diabetes that is often overlooked?

Being clinically silent Signup and view all the answers

What is the role of aldose reductase in the pathology of diabetes?

Converts glucose to sorbitol, causing osmotic damage Signup and view all the answers

Which consequence of diabetes primarily affects the kidneys?

Kimmelstiel-Wilson nodules formation Signup and view all the answers

What percentage of pancreatic neoplasms are accounted for by islet cell tumors?

Less than 5% Signup and view all the answers

What is the primary role of insulin secreted by beta cells in the islets of Langerhans?

To decrease serum glucose levels Signup and view all the answers

Which immune response is primarily responsible for the destruction of beta cells in Type 1 Diabetes Mellitus?

T lymphocyte-mediated autoimmune destruction Signup and view all the answers

In Type 1 Diabetes Mellitus, what leads to hyperglycemia during fasting states?

Excess glucagon leading to gluconeogenesis Signup and view all the answers

What is a characteristic complication of Type 1 Diabetes Mellitus that may arise during periods of stress?

Diabetic ketoacidosis Signup and view all the answers

Which of the following features is NOT typically associated with Type 1 Diabetes Mellitus?

Obesity Signup and view all the answers

What is the mechanism through which glucagon increases blood glucose levels?

Stimulation of glycogenolysis Signup and view all the answers

Which of the following is a sign of diabetic ketoacidosis?

Kussmaul respirations Signup and view all the answers

What best describes the pathophysiology of Type 2 Diabetes Mellitus?

End-organ insulin resistance Signup and view all the answers

Study Notes

Endocrine Pancreas

Composed of clusters of cells called islets of Langerhans
Each islet contains multiple cell types, each producing a unique hormone
Insulin is produced by beta cells, located centrally within the islets
Insulin is a major anabolic hormone, increasing glucose uptake by skeletal muscle and adipose tissue, reducing serum glucose
Increased glucose uptake leads to glycogen, protein, and lipid synthesis
Glucagon is produced by alpha cells, acting in opposition to insulin, increasing blood glucose levels during fasting (via glycogenolysis and lipolysis)

Type 1 Diabetes Mellitus

Characterized by insulin deficiency due to autoimmune destruction of beta cells
Often caused by T lymphocytes
Inflammation of islets is common
Associated with HLA-DR3 and HLA-DR4
Autoantibodies against insulin are often present years before clinical diagnosis
Initial symptoms appear in childhood
High blood glucose, reduced glucose uptake by fat and skeletal muscle due to lack of insulin
Hyperglycemia is a key characteristic

Type 2 Diabetes Mellitus

Predominantly an end-organ insulin resistance disorder
Characterized by hyperglycemia
Accounts for 90% of diabetes cases, most prevalent in middle-aged obese adults.
Obesity is linked to decreased insulin receptors
High genetic predisposition
Early in the disease, insulin levels may be elevated, but later, beta cell exhaustion leads to insulin deficiency
Often clinically silent in early stages; polyuria, polydipsia, and hyperglycemia are common clinical features
Diagnosis based on random glucose levels exceeding 200 mg/dL, fasting glucose over 126 mg/dL or glucose tolerance test showing over 200 mg/dL two hours after glucose consumption

Long-Term Consequences of Diabetes

Nonenzymatic glycosylation (NEG) of vascular basement membranes leads to atherosclerosis, cardiovascular disease, and peripheral vascular disease.
NEG of small vessels leads to hyaline arteriolosclerosis, affecting kidneys and resulting in small scarred kidneys.
NEG of hemoglobin forms glycated hemoglobin (HbA1c), a marker of blood glucose control.
Osmotic damage occurs as glucose enters Schwann cells, pericytes, and lens; this leads to nerve damage, blindness, and cataracts.

Pancreatic Endocrine Neoplasms

Tumors of islet cells, a relatively rare component of pancreatic neoplasms (<5% of pancreatic tumors)
Often associated with MEN-1 syndrome, alongside parathyroid hyperplasia and pituitary adenomas
Insulinomas are characterized by episodic hypoglycemia, relieved by glucose administration
Gastrinomas cause treatment-resistant peptic ulcers (Zollinger-Ellison syndrome)
Somatostatinomas result in achlorhydria and cholelithiasis with steatorrhea
VIPomas manifest as watery diarrhea, hypokalemia, and achlorhydria.

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Description

Explore the intricate functions of the endocrine pancreas and the implications of Type 1 Diabetes Mellitus. This quiz covers the physiological role of insulin and glucagon, as well as the autoimmune factors leading to insulin deficiency in Type 1 Diabetes. Test your knowledge on the islets of Langerhans and the pathophysiology of diabetes.