Insulin Action on Liver and Adipose Tissues
41 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary effect of insulin on blood glucose levels?

  • It has no significant effect on blood glucose levels.
  • It decreases blood glucose levels. (correct)
  • It maintains blood glucose levels at a constant rate.
  • It increases blood glucose levels.

    • Which of the following hormones primarily facilitates the conversion of glucose to glycogen in the liver?

  • Insulin (correct)
  • Cortisol
  • Glucagon
  • Epinephrine

    • What is the role of GSK3 in the context of insulin action?

  • It stimulates gluconeogenesis in the liver.
  • It promotes the breakdown of glycogen.
  • It regulates hepatic glycogen synthesis. (correct)
  • It enhances glucose uptake by muscle cells.

    • Which molecular mechanism does insulin utilize to mediate glucose uptake in adipose tissue?

    <p>Activation of the insulin receptor substrate.</p> Signup and view all the answers

    In what way does insulin affect gluconeogenesis?

    <p>It suppresses gluconeogenesis.</p> Signup and view all the answers

    Which of the following statements about insulin's physiological actions is false?

    <p>Insulin enhances glycogenolysis in the liver.</p> Signup and view all the answers

    Which of the following is NOT a direct action of insulin on cellular metabolism?

    <p>Promoting fatty acid oxidation.</p> Signup and view all the answers

    What is the primary action of insulin in the liver regarding glucose metabolism?

    <p>Promotion of glucose storage as glycogen</p> Signup and view all the answers

    Which enzyme is associated with the prevention of futile cycling in gluconeogenesis?

    <p>Fructose-1,6-bisphosphatase</p> Signup and view all the answers

    How does glucagon affect the PFK2/FBPase-2 enzyme system?

    <p>It induces phosphorylation of PFK2</p> Signup and view all the answers

    What role does malonyl CoA play in fatty acid metabolism?

    <p>Inhibits fatty acid oxidation</p> Signup and view all the answers

    In the context of insulin's effect, which process is suppressed in the adipose tissue?

    <p>Triglyceride breakdown</p> Signup and view all the answers

    Which substrate is essential for the action of PEPCK in gluconeogenesis?

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

    What metabolic pathway is primarily promoted by insulin in relation to fatty acids?

    <p>Fatty acid synthesis</p> Signup and view all the answers

    Which condition is likely caused by dysregulation of lipoprotein transport mechanisms in diabetes?

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

    Which of the following enzyme activities is associated with insulin's promotion of glucose uptake into the liver?

    <p>GLUT2 activity</p> Signup and view all the answers

    What triggers the secretion of glucagon?

    <p>Decrease in blood glucose levels</p> Signup and view all the answers

    Which process is stimulated by glucagon in the liver?

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

    What is the primary role of insulin in blood glucose regulation?

    <p>To facilitate glucose uptake into cells</p> Signup and view all the answers

    How does glucagon affect fatty acid oxidation in adipose tissues?

    <p>Stimulates HSL</p> Signup and view all the answers

    What is the normal range for blood glucose levels in mmols/l?

    <p>3.9-5.9</p> Signup and view all the answers

    What is one of the main actions of glucagon regarding glycogen?

    <p>Increase glycogenolysis</p> Signup and view all the answers

    Which of the following is NOT a function of glucagon?

    <p>Stimulation of glucose uptake in tissues</p> Signup and view all the answers

    What is the secondary messenger associated with glucagon action?

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

    Which statement accurately describes the relationship between insulin and glucagon?

    <p>Insulin opposes the actions of glucagon</p> Signup and view all the answers

    Which hormone acts as a first-line response in counter-regulatory mechanisms?

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

    What is characteristic of type 1 diabetes in comparison to type 2 diabetes?

    <p>Pancreatic beta cell destruction</p> Signup and view all the answers

    According to the WHO criteria, what fasting plasma glucose (FPG) level indicates diabetes?

    <p>7.0 mmol/l</p> Signup and view all the answers

    What factor can influence HbA1c results and is particularly problematic in under-resourced countries?

    <p>Prevalence of anemia</p> Signup and view all the answers

    Which classification of diabetes includes cases where a person is diagnosed by exclusion of type 1 diabetes and other conditions?

    <p>Type 2 Diabetes Mellitus (T2DM)</p> Signup and view all the answers

    What is the criteria for pre-diabetes based on HbA1c levels according to the ADA?

    <p>5.7-6.4%</p> Signup and view all the answers

    What is the major feature of diabetes mellitus?

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

    What condition can result from glucosuria in individuals with diabetes?

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

    What was a common dietary treatment for diabetes mellitus before insulin became available?

    <p>Starvation diets</p> Signup and view all the answers

    What severe outcome is associated with untreated diabetes mellitus in children, as illustrated in the content?

    <p>Renal failure</p> Signup and view all the answers

    What was a consequence of the high extracellular glucose observed after meals in individuals with diabetes?

    <p>Intracellular glucose deficiency</p> Signup and view all the answers

    What did the content describe one child resorting to due to starvation from diabetes?

    <p>Toothpaste mixed with birdseed</p> Signup and view all the answers

    Which of the following is NOT a risk factor mentioned for children with diabetes before insulin was discovered?

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

    What does the presence of glucose in urine signify in a diabetic patient?

    <p>Osmotic diuresis</p> Signup and view all the answers

    What philosophical remark did the physician Allen make regarding the child's situation?

    <p>Confessions are key to treatment.</p> Signup and view all the answers

    Which of these complications is highlighted as a potential consequence of untreated diabetes mellitus?

    <p>Brain damage</p> Signup and view all the answers

    Study Notes

    Insulin Action on Liver and Adipose Tissues

    • Normal blood glucose levels are 3.9-5.9 mmol/L
    • Insulin promotes glucose uptake into cells
    • Insulin stimulates glycogen synthesis in the liver and skeletal muscle
    • Insulin inhibits glycogenolysis in the liver
    • Insulin inhibits gluconeogenesis
    • Insulin promotes glucose conversion to fatty acids that are then transported to adipose tissue for storage
    • Insulin suppresses triglyceride breakdown in adipose tissue
    • Insulin treatment can lead to weight gain

    Insulin Signaling Pathway

    • Insulin binds to its receptor on the cell membrane
    • This triggers a cascade of phosphorylation events involving IRS, PI3K, p85, p110, PDK1, mTORC2, and Akt
    • The cascade leads to the activation of Akt
    • Akt regulates proteins involved in glycogen synthesis, inhibition of gluconeogenesis, and GLUT4 translocation
    • Akt also affects proteins involved in protein translation to further affect the process of gluconeogenesis
    • GSK3 regulates hepatic glycogen synthesis
    • FOXO regulates hepatic gluconeogenesis

    Physiological Actions of Insulin

    • Insulin promotes glucose uptake into cells
    • Insulin promotes glycogen formation in skeletal muscle and liver
    • Insulin inhibits glycogen breakdown to glucose (glycogenolysis)
    • Insulin inhibits the formation of glucose from non-carbohydrate substances (gluconeogenesis)

    Counterregulation

    • Counterregulatory hormones like glucagon oppose the effects of insulin.
    • Glucagon increases glycogenolysis and gluconeogenesis
    • Glucagon suppresses glycolysis
    • Glucagon increases fatty acid oxidation
    • Glucagon stimulates HSL in adipose tissue

    Diabetes Mellitus

    • Diabetes is characterized by high blood glucose levels.
    • Major feature: Hyperglycaemia (>200 mg/100 mL, >16 mmol/L)
    • Glucosuria: Glucose in urine
    • Dehydration and circulatory failure may occur due to the large osmotic diuresis
    • Following a meal, cells may fail to properly absorb glucose.
    • Extracellular glucose levels increase, while intracellular glucose levels decrease
    • Before insulin, treatments for diabetes included starvation diets.

    Types of Diabetes

    • Type 1 Diabetes Mellitus: Pancreatic beta cell destruction; insulin is required for survival. Characterized by the presence of anti-GAD or anti-islet cell antibodies.
    • Type 2 Diabetes Mellitus: A diagnosis of exclusion. A person is considered to have Type 2 diabetes if they do not have Type 1 diabetes, monogenic diabetes, or another medical condition suggesting secondary diabetes. Insulin resistance is a common feature.
    • MODY: Monogenic diabetes
    • Secondary causes, such as drugs, pancreatic issues, or endocrine problems.

    Criteria for Diabetes

    • WHO criteria for diabetes:

      • Fasting plasma glucose (FPG) ≥ 7.0 mmol/L
      • Oral glucose tolerance test (OGTT) 2-hour glucose ≥ 11.1 mmol/L after a 75g glucose load
      • Impaired glucose tolerance (IGT): FPG < 7.0 mmol/L but 2-hour OGTT ≥ 7.8 mmol/L, but <11.1 mmol/L
      • Impaired fasting glucose (IFG): FPG between 6.1 and 7.0 mmol/L

    • ADA criteria for diabetes diagnosis: HbA1c > 6.5%

    • Pre-diabetes: HbA1c 5.7-6.4%

    Other important factors

    • The HbA1c result is influenced by factors including anaemia, haemoglobin abnormalities, pregnancy, and uraemia.
    • Dysregulation of lipoprotein (VLDL) and fatty acid transport between liver and adipose tissues may occur in diabetes, leading to hyperlipidaemia.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Fuel Use: Insulin Action PDF

    Description

    This quiz explores the role of insulin in regulating blood glucose levels and its impact on liver and adipose tissues. It covers insulin signaling pathways and mechanisms such as glycogen synthesis and fat storage. Test your understanding of these crucial metabolic processes!

    More Like This

    Insulin Action on Liver and Adipose Tissues
    41 questions

    Insulin Action on Liver and Adipose Tissues

    ShinyLongBeach6025 avatar
    ShinyLongBeach6025
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser