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Questions and Answers
What is the primary function of β cells in the pancreas?
What is the primary function of β cells in the pancreas?
At what gestational age are functional β cells present?
At what gestational age are functional β cells present?
What is produced during the final cleavage of proinsulin?
What is produced during the final cleavage of proinsulin?
How is blood glucose concentration conventionally expressed in most countries?
How is blood glucose concentration conventionally expressed in most countries?
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What is the fasting blood glucose level considered normal for humans?
What is the fasting blood glucose level considered normal for humans?
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What is a significant challenge in assessing the progression of Type 1 Diabetes Mellitus (T1DM) regarding pancreatic beta cell function?
What is a significant challenge in assessing the progression of Type 1 Diabetes Mellitus (T1DM) regarding pancreatic beta cell function?
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How does manganese assist in the imaging of pancreatic beta cells through MRI?
How does manganese assist in the imaging of pancreatic beta cells through MRI?
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Which cell type in the pancreas is responsible for the secretion of insulin?
Which cell type in the pancreas is responsible for the secretion of insulin?
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What defines the endocrine function of the pancreas?
What defines the endocrine function of the pancreas?
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What is the primary role of preproinsulin in pancreatic beta cells?
What is the primary role of preproinsulin in pancreatic beta cells?
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What is the primary function of the Islets of Langerhans in the pancreas?
What is the primary function of the Islets of Langerhans in the pancreas?
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Who is credited with demonstrating that blood glucose levels in a diabetic dog could be lowered by pancreas extract?
Who is credited with demonstrating that blood glucose levels in a diabetic dog could be lowered by pancreas extract?
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In what year was purified insulin produced by James Collip?
In what year was purified insulin produced by James Collip?
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Which cells are primarily responsible for the exocrine function of the pancreas?
Which cells are primarily responsible for the exocrine function of the pancreas?
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Which significant medical advancement was recognized with a Nobel Prize in 1923?
Which significant medical advancement was recognized with a Nobel Prize in 1923?
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What is the primary function of the endocrine pancreas?
What is the primary function of the endocrine pancreas?
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What specific event occurred in 1889 related to diabetes research?
What specific event occurred in 1889 related to diabetes research?
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Which statement accurately describes proinsulin?
Which statement accurately describes proinsulin?
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Which of these statements describes the primary composition of the pancreas?
Which of these statements describes the primary composition of the pancreas?
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Which stimuli primarily triggers insulin secretion from the pancreas?
Which stimuli primarily triggers insulin secretion from the pancreas?
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What did Eugene Opie discover about the Islets of Langerhans in 1901?
What did Eugene Opie discover about the Islets of Langerhans in 1901?
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How does glucagon primarily function in the body?
How does glucagon primarily function in the body?
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Which disorder is primarily associated with dysfunction of the endocrine pancreas?
Which disorder is primarily associated with dysfunction of the endocrine pancreas?
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What characterizes a closed-loop system for managing type 1 diabetes?
What characterizes a closed-loop system for managing type 1 diabetes?
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What is one key role of insulin in glucose homeostasis?
What is one key role of insulin in glucose homeostasis?
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Which of the following best describes the overall structure of the pancreas?
Which of the following best describes the overall structure of the pancreas?
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At what blood glucose concentration does the maximum insulin response occur?
At what blood glucose concentration does the maximum insulin response occur?
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Which amino acids are known to stimulate insulin release?
Which amino acids are known to stimulate insulin release?
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What effect does epinephrine have on glucagon release?
What effect does epinephrine have on glucagon release?
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Which of the following factors does NOT stimulate insulin release?
Which of the following factors does NOT stimulate insulin release?
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What is the role of preproglucagon in glucagon synthesis?
What is the role of preproglucagon in glucagon synthesis?
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During hypoglycemia, which hormone is primarily released to raise blood glucose levels?
During hypoglycemia, which hormone is primarily released to raise blood glucose levels?
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What is the effect of high blood glucose concentration on glucagon release?
What is the effect of high blood glucose concentration on glucagon release?
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Which incretin is known to stimulate insulin secretion?
Which incretin is known to stimulate insulin secretion?
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What is the physiological effect of injected insulin compared to ingested glucose on insulin secretion?
What is the physiological effect of injected insulin compared to ingested glucose on insulin secretion?
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What role does somatostatin play in insulin and glucagon regulation?
What role does somatostatin play in insulin and glucagon regulation?
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Study Notes
Pancreas Structure & Function
- The pancreas is an accessory organ of digestion.
- It has both endocrine and exocrine functions.
- It is found retroperitoneally at vertebral level L1/L2.
Exocrine Functions
- The exocrine portion produces bicarbonate and pancreatic lipases and proteases.
Endocrine Functions
- The endocrine portion comprises the islets of Langerhans.
- Islets of Langerhans include alpha, beta, delta, and PP cells.
- Alpha cells secrete glucagon.
- Beta cells secrete insulin.
- Delta cells secrete somatostatin.
- PP cells secrete pancreatic polypeptide.
Insulin Synthesis and Release
- Insulin synthesis begins with the preproinsulin gene.
- Cleavage of preproinsulin produces proinsulin.
- Cleavage of proinsulin produces insulin and C-peptide in equal amounts.
- The final product is the bioactive peptide insulin.
- Beta cell insulin release is stimulated by high blood glucose concentration, amino acids (especially leucine, isoleucine, alanine, and arginine), incretins (GIP and GLP-1), glucagon, hyperkalemia, and vagal nerve stimulation.
- Insulin release is inhibited by norepinephrine, epinephrine, and somatostatin.
- Blood glucose concentrations below 2.8 mmol/L result in no insulin production.
- Half-maximal insulin response occurs at 8.3 mmol/L.
- Maximum insulin response occurs at 16.7 mmol/L.
Glucagon Synthesis and Release
- Glucagon synthesis begins with the preproglucagon gene.
- Cleavage of preproglucagon produces glucagon.
- The final product is the bioactive peptide glucagon.
- Alpha cell glucagon release is stimulated by hypoglycemia, amino acids (mainly arginine and alanine), GIP, and epinephrine.
- Glucagon release is inhibited by amylin, insulin, somatostatin, GLP-1, and hyperglycemia.
Glucose Homeostasis
- Insulin and glucagon are key regulators of glucose homeostasis.
- Insulin promotes glucose uptake and storage by cells, lowering blood glucose.
- Glucagon promotes glycogen breakdown and gluconeogenesis, raising blood glucose.
Diseases Associated with Pancreatic Dysfunction
- Type 1 diabetes mellitus is caused by autoimmune destruction of beta cells, resulting in insulin deficiency.
- Type 2 diabetes mellitus is characterized by insulin resistance and inadequate insulin secretion.
- Pancreatitis can damage both the endocrine and exocrine pancreas, leading to impaired function.
- Pancreatic cancer can arise from either exocrine or endocrine tissue.
Closed-Loop System for Type 1 Diabetes
- Closed-loop systems use continuous glucose monitoring and automated insulin delivery to mimic physiological insulin regulation.
- This system utilizes sensors, algorithms, and pumps to deliver insulin based on real-time glucose readings.
Emerging Methods for Quantification of Pancreatic Dysfunction in T1DM
- Manganese enhanced magnetic resonance imaging (MRI) is emerging as a potential tool for evaluating beta cell function.
- Manganese enters cells via voltage-gated calcium channels, accumulating in functional cells like pancreatic beta cells.
- Using manganese contrast in MRI can provide insights into beta cell function, aiding in the diagnosis, management, and evaluation of new therapies for T1DM.
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Description
Test your knowledge on the structure and functions of the pancreas, including its endocrine and exocrine roles. Explore the details of insulin synthesis, the islets of Langerhans, and more in this focused quiz. Perfect for students studying human physiology.
