Endocrine pancreas
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Questions and Answers

What are the main components of the pancreas?

Exocrine and endocrine functions

The exocrine pancreas is composed of two types of cells. What are these cells?

Pancreatic acinar cells and duct cells

What is the function of the duct cells?

They serve as a “roadway” to duodenum

What is the function of the exocrine pancreas?

<p>It secretes digestive enzymes into the lumen of the duodenum</p> Signup and view all the answers

The endocrine pancreas is composed of __________

<p>Islets of Langerhans</p> Signup and view all the answers

What are the cell types found in the islets of langerhans in the endocrine pancreas?

<p>Alpha, beta, Delta and F cells</p> Signup and view all the answers

Each cell produces a distinct hormone.

<p>Alpha = Glucagon Beta = Insulin Delta = Somatostatin F = Pancreatic polypeptide</p> Signup and view all the answers

What hormones from the pancreas are involved in glucose metabolism?

<p>Glucagon, insulin, somatostatin and pancreatic polypeptide</p> Signup and view all the answers

Beta cells secrete insulin in response to hypoglycemia

<p>False</p> Signup and view all the answers

Describe the process of insulin synthesis and secretion

<p>Preprohormone in endoplasmic reticulum cleaved by enzymes to prohormone before getting secreted, Prohormone (aka proinsulin) moves into Golgi apparatus where its packaged in secretory vesicles that contain proinsulin and enzymes and further processed into insulin and the connecting C peptide, insulin and c peptide are released by exocytosis into extracellular space, insulin is transported by blood vessels to its target organ</p> Signup and view all the answers

How many chains make up insulin and which ones are they?

<p>2 chains, alpha and beta</p> Signup and view all the answers

Amino acid sequences forming the insulin protein are different between species. For example, dogs can’t use insulin from pigs

<p>False</p> Signup and view all the answers

Species specific differences in insulin structure

<p>Human insulin differs from feline by = 4 aa Porcine insulin differs from human insulin by = 1 aa Bovine insulin differs from feline insulin by = 1 aa Porcine insulin differs from feline insulin by = 1 aa</p> Signup and view all the answers

In carnivores, which substance primarily stimulates insulin secretion?

<p>Amino acids</p> Signup and view all the answers

Which of the following is a stimulant for insulin release specifically in humans?

<p>Fatty acids</p> Signup and view all the answers

What is the primary factor influencing insulin secretion in omnivores?

<p>Glucose</p> Signup and view all the answers

Which statement is true regarding insulin secretion in ruminants?

<p>Volatile fatty acids stimulate secretion.</p> Signup and view all the answers

Which of the following variables does NOT influence insulin release?

<p>Genetic variables</p> Signup and view all the answers

What hormones stimulate insulin secretion?

<p>Growth hormone and glucagon</p> Signup and view all the answers

Nutrition is a stimulator factor for insulin secretion. What are these nutrients?

<p>Glucose, amino acids, fatty acids and ketones</p> Signup and view all the answers

Which of the following hormones is NOT an inhibitor of insulin secretion?

<p>GIP</p> Signup and view all the answers

List all the hormones that inhibit insulin secretion (ones important in class)

<p>Adrenocorticosteroids, somatostatin, Adrenalin, noradrenalin</p> Signup and view all the answers

Name and describe the phases of insulin secretion

<p>Acute phase releases preformed insulin and the chronic phase synthesis of protein</p> Signup and view all the answers

GLUT2 transporters aer found on both beta and alpha cells

<p>False</p> Signup and view all the answers

Highlight the process in which glucose enters the beta cell to release insulin

<p>GLUT1 transporter on the membrane surface enters, which causes an increase in ATP production, this blocks the potassium ATP sensitive channel, causes depolarization in the cell which then allows voltage gated calcium channels to open, an increase in Ca activates vesicles to promote exocytosis of stored insulin</p> Signup and view all the answers

What would happen with the addition of sulfonylureas affect insulin release?

<p>It will act directly on ATP production to increase exocytosis of stored insulin</p> Signup and view all the answers

What is the membrane receptor that insulin binds to on target tissues and how many molecules need to bind in order to activate it?

<p>Insulin receptor tyrosine kinase, two</p> Signup and view all the answers

Describe the physiological effects of insulin

<p>The goal of insulin is to lower the blood concentration of glucose, fatty acids and amino acids. It does this by promoting intracellular conversion of these compounds to their storage forms</p> Signup and view all the answers

What are the most important insulin sensitive tissues?

<p>Liver, muscle and adipose tissue</p> Signup and view all the answers

What is the primary mechanism by which insulin facilitates glucose entry into the cells?

<p>Increases the number of GLUT-4 transporters in the cell membrane</p> Signup and view all the answers

Which of the following statements about GLUT-4 is true?

<p>GLUT-4 can be stimulated by both insulin and exercise</p> Signup and view all the answers

What type of stimulation is referred to as non-insulin mediated action in relation to GLUT-4?

<p>Stimulation by physical activity</p> Signup and view all the answers

Which glucose transporter is specifically characterized as insulin-sensitive?

<p>GLUT-4</p> Signup and view all the answers

Which of the following is NOT a role of GLUT-4 in glucose metabolism?

<p>Increases basal glucose levels in the bloodstream</p> Signup and view all the answers

Insulin is inactivated mainly by what two organs?

<p>Liver</p> Signup and view all the answers

In adipose tissue, insulin inhibits lipolysis and promotes adipose deposition

<p>True</p> Signup and view all the answers

What hormones counteract the effects of insulin?

<p>Cortisol, growth hormone, glucagon, epinephrine/norepinephrine</p> Signup and view all the answers

Which of the following counter regulatory hormones are acute phase?

<p>Glucagon</p> Signup and view all the answers

What is one effect of cortisol during the chronic phase of hypoglycemia?

<p>Increases lipolysis</p> Signup and view all the answers

In addition to glucagon, which other hormone aids in gluconeogenesis during acute hypoglycemia?

<p>Epinephrine</p> Signup and view all the answers

Which counter regulatory hormone is primarily responsible for increasing muscular lipolysis during hypoglycemia?

<p>Epinephrine</p> Signup and view all the answers

Glucagon is a polypeptide hormone produced in alpha cells of pancreatic islets

<p>True</p> Signup and view all the answers

What stimulates the synthesis of glucagon?

<p>Hypoglycemia</p> Signup and view all the answers

Describe glucagon synthesis

<p>Glucose enters cells via GLUT transporter, Glucose is used to generate ATP, Low glucose results in low intracellular ATP, low ATP levels close ATP-sensitive potassium channels, effluent of potassium is reduced and causes the cell membrane to change, it in turn opens voltage dependent calcium channels and causes an influx of Ca to trigger exocytosis of glucagon.</p> Signup and view all the answers

What is the purpose of glucagon within the body?

<p>It opposes most insulin actions, maintain blood glucose concentration</p> Signup and view all the answers

Glucagon synthesis is promoted by voltage-dependent K+ channels

<p>False</p> Signup and view all the answers

What is the primary effect of glucagon on the liver?

<p>Enhances glucose availability to other cells</p> Signup and view all the answers

Which amino acids are specifically known to stimulate both insulin and glucagon release?

<p>Alanine and Arginine</p> Signup and view all the answers

What is one of the key actions of glucagon on adipocytes?

<p>Promotes lipolysis</p> Signup and view all the answers

In obligate carnivores, what effect does glucagon have in response to increased amino acid levels?

<p>Stimulates insulin release</p> Signup and view all the answers

What is the primary role of pancreatic somatostatin in the gastrointestinal tract?

<p>Inhibits secretion from Islet of Langerhans cells</p> Signup and view all the answers

Which cells in the pancreas are responsible for producing pancreatic polypeptide?

<p>F or PP cells</p> Signup and view all the answers

What effect does somatostatin have on pancreatic polypeptide secretion?

<p>Inhibits its secretion</p> Signup and view all the answers

Which of the following is a known effect of pancreatic polypeptide on the gastrointestinal tract?

<p>Decreases gastric emptying</p> Signup and view all the answers

Which of these statements about the actions of somatostatin is correct?

<p>It decreases motility of the gastrointestinal tract.</p> Signup and view all the answers

What is the primary difference between absolute and relative insulin deficiency in diabetes mellitus?

<p>Absolute insulin deficiency is the complete absence of insulin, characteristic of type 1 diabetes, while relative insulin deficiency refers to insulin that is not functioning properly, as seen in type 2 diabetes.</p> Signup and view all the answers

List two primary clinical signs associated with hyperglycemia in diabetes mellitus.

<p>Two primary clinical signs are polyuria (increased urination) and polydipsia (increased thirst).</p> Signup and view all the answers

Explain how insulin deficiency affects glucagon production.

<p>Insulin deficiency leads to increased glucagon production due to the loss of inhibition, causing hyperglucagonemia and disrupting the regulation of glucagon secretion.</p> Signup and view all the answers

What role does hormone-sensitive lipase play in diabetes mellitus?

<p>Hormone-sensitive lipase is activated by insulin deficiency, leading to lipolysis of stored fat and increased free fatty acids in the blood.</p> Signup and view all the answers

Describe the metabolic effect of insulin deficiency on muscle tissue.

<p>Insulin deficiency results in protein depletion and increased plasma amino acids due to increased protein catabolism and halted protein synthesis.</p> Signup and view all the answers

How does glucagon promote gluconeogenesis, particularly in times of insulin deficiency?

<p>Glucagon stimulates gluconeogenesis by promoting the conversion of amino acids and glycerol to glucose in the liver, especially when insulin levels are low.</p> Signup and view all the answers

Identify one potential effect of excess free fatty acids (FFA) in diabetic patients.

<p>Excess FFA can lead to increased liver production of triglycerides and cholesterol, contributing to hyperlipidemia.</p> Signup and view all the answers

What is the significance of paradoxical hyperglucagonemia in diabetes mellitus?

<p>Paradoxical hyperglucagonemia indicates a loss of regulatory control over glucagon secretion due to beta cell deficiency and insulin resistance, exacerbating hyperglycemia.</p> Signup and view all the answers

What is the primary underlying cause of Type I diabetes in dogs?

<p>Autoimmune destruction of beta cells</p> Signup and view all the answers

What factor contributes most significantly to the development of cataracts in diabetic patients?

<p>Accumulation of sorbitol and galactitol</p> Signup and view all the answers

Which of the following statements accurately describes the nature of Type II diabetes in cats?

<p>It results from relative insulin deficiency and insulin resistance.</p> Signup and view all the answers

Which condition is most likely to impair insulin secretion and cause beta cell dysfunction in cats with obesity?

<p>Islet amyloidosis</p> Signup and view all the answers

What role does amylin play in the context of diabetes in cats?

<p>It causes aggregation leading to amyloid deposition in pancreatic islets.</p> Signup and view all the answers

Which of the following statements about the relationship between obesity and diabetes in cats is true?

<p>Healthy beta cells can adapt to obesity and insulin resistance.</p> Signup and view all the answers

What is the significance of aldose reductase in diabetic cataract formation?

<p>It converts glucose into sorbitol and galactitol.</p> Signup and view all the answers

Which of the following factors is least associated with the etiopathogenesis of Type II diabetes in cats?

<p>Increased glucose utilization</p> Signup and view all the answers

What is one of the common causes of insulin resistance in cats?

<p>Obesity.</p> Signup and view all the answers

Describe the condition under which clinical remission can occur in type 2 diabetes mellitus in cats.

<p>Clinical signs disappear and blood glucose levels normalize, allowing for the discontinuation of insulin treatment.</p> Signup and view all the answers

What is a common chronic complication of diabetes in cats and its primary cause?

<p>Diabetic neuropathy, primarily caused by hyperglycemia leading to nerve injury.</p> Signup and view all the answers

What role does glucotoxicity play in the context of beta cell dysfunction in cats with diabetes?

<p>Glucotoxicity is a reversible condition affecting beta cell function, which can lead to complications in diabetes.</p> Signup and view all the answers

What are the clinical signs of diabetic neuropathy in cats, and how can they vary?

<p>Clinical signs can range from very mild to severe, affecting mobility and overall nerve function.</p> Signup and view all the answers

DKA is not a severe complication of Diabetes mellitus

<p>False</p> Signup and view all the answers

Which counterregulatory hormone is the most influential ketogenenic hormone?

<p>Glucagon</p> Signup and view all the answers

What electrolytes are affected by DKA?

<p>Na, K and Phosphate</p> Signup and view all the answers

What physiological change occurs as a result of acidosis due to excessive ketone accumulation?

<p>Increase in [H+]</p> Signup and view all the answers

Which factors contribute to the kidney's failure to compensate during Diabetic Ketoacidosis (DKA)?

<p>Physiochemical properties of ketone bodies</p> Signup and view all the answers

What is the most likely consequence of overwhelming the body's buffering system during acidosis?

<p>Inability to maintain stable pH</p> Signup and view all the answers

Which molecule's accumulation is primarily responsible for the acidosis associated with diabetes?

<p>Beta hydroxybutyrate</p> Signup and view all the answers

What primary effect does untreated acidosis have on the body's acid-base balance?

<p>Impairment of metabolic processes</p> Signup and view all the answers

What type of pancreatic tumor is characterized by the excessive production of insulin regardless of blood glucose levels?

<p>Insulinoma</p> Signup and view all the answers

Which clinical sign is most commonly associated with glucagonoma?

<p>Superficial necrolytic dermatitis</p> Signup and view all the answers

In which species is insulinoma rarely observed?

<p>Cats</p> Signup and view all the answers

Which cell type is responsible for synthesizing and secreting glucagon?

<p>Alpha cells</p> Signup and view all the answers

What is a significant characteristic of the insulinoma tumors in terms of their insulin production?

<p>They produce insulin regardless of blood glucose levels.</p> Signup and view all the answers

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