Liver Functions Overview
98 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which process is responsible for the conversion of glucose to glycogen for storage?

  • Lipolysis
  • Glycogenesis (correct)
  • Gluconeogenesis
  • Glycogenolysis

    • During fasting or high energy demand, which process synthesizes glucose from non-carbohydrate sources?

  • Ketogenesis
  • Glycogenesis
  • Glycogenolysis
  • Gluconeogenesis (correct)

    • Which compound is produced by the breakdown of fatty acids during β-oxidation?

  • Lactate
  • Glycerol
  • Glycogen
  • Acetyl-CoA (correct)

    • What is the main role of albumin in protein synthesis?

    <p>Regulation of blood osmotic pressure</p> Signup and view all the answers

    Which vitamins are specifically stored in the liver?

    <p>Fat-soluble vitamins</p> Signup and view all the answers

    What process involves the conversion of ammonia into urea for excretion?

    <p>Urea cycle</p> Signup and view all the answers

    Which structure is responsible for the recycling of iron from aged red blood cells?

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

    What is the role of transferrin in iron metabolism?

    <p>Binding of Fe³⁺ in the blood</p> Signup and view all the answers

    Which factor is not associated with the liver's role in lipid metabolism?

    <p>Synthesis of chylomicrons</p> Signup and view all the answers

    What role do Kupffer cells play in the liver's functions?

    <p>Degrading old or damaged proteins</p> Signup and view all the answers

    Which fat-soluble vitamin is primarily stored in the liver?

    <p>Vitamin A</p> Signup and view all the answers

    How does the liver contribute to detoxification processes?

    <p>Through the urea cycle for ammonia conversion</p> Signup and view all the answers

    Which of the following lipoproteins is primarily responsible for transporting dietary fats?

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

    What enhances the uptake of chylomicrons in the body?

    <p>Receptors like Niemann-Pick C</p> Signup and view all the answers

    Which statement about fat metabolism is true regarding muscle cells?

    <p>Muscle cells can use chylomicrons as an energy source.</p> Signup and view all the answers

    Which process is associated with the liver's role in protein synthesis?

    <p>Production of clotting factors</p> Signup and view all the answers

    Which hormone, produced by the liver, is primarily involved in the regulation of blood glucose levels?

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

    What is the primary function of albumin in the blood?

    <p>Maintaining osmotic pressure</p> Signup and view all the answers

    Which vitamin is specifically known for being stored in the liver as a fat-soluble vitamin?

    <p>Vitamin A</p> Signup and view all the answers

    Which process in the liver is primarily responsible for the removal of ammonia from the body?

    <p>Urea cycle</p> Signup and view all the answers

    Which metabolic process in the liver primarily utilizes fatty acids to produce energy?

    <p>Beta-oxidation</p> Signup and view all the answers

    What role does the hepatic portal vein play in the detoxification process?

    <p>It delivers nutrients and toxins from the digestive tract.</p> Signup and view all the answers

    Which component of the liver lobule is primarily involved in blood filtration?

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

    Which form of vitamin B is notably stored in the liver?

    <p>Vitamin B12 (Cobalamin)</p> Signup and view all the answers

    Match the liver cell types to their primary functions:

    <p>Hepatocytes = Metabolism and protein synthesis Liver Endothelial Cells (LEC) = Facilitating substance exchange Stellate Cells = Storing vitamin A and fibrosis role Kupffer Cells = Phagocytosing pathogens and debris</p> Signup and view all the answers

    Match the components of the portal triad with their descriptions:

    <p>Portal vein branch = Brings nutrient-rich blood from the digestive organs Hepatic artery branch = Supplies oxygen-rich blood to the liver Bile duct = Drains bile produced by hepatocytes Liver sinusoids = Capillaries where blood from both portal vein and hepatic artery mix</p> Signup and view all the answers

    Match the liver's blood flow sequence with its components:

    <p>Blood from liver sinusoids = Collected by central veins Central veins = Drain into larger hepatic veins Hepatic veins = Empty blood into the inferior vena cava Inferior vena cava = Returns blood to the heart via right atrium</p> Signup and view all the answers

    Match the following functions with the corresponding liver cell types:

    <p>Hepatocytes = Bile production Kupffer Cells = Immune response Stellate Cells = Vitamin A storage Liver Endothelial Cells (LEC) = Blood vessel lining</p> Signup and view all the answers

    Match the following hepatic structures with their roles:

    <p>Bile canaliculi = Transport bile from hepatocytes Hepatic veins = Drain filtered blood from the liver Liver sinusoids = Site of blood filtration Inferior vena cava = Carries blood to the heart</p> Signup and view all the answers

    Match the liver functions with their descriptions:

    <p>Vitamin Storage = Stores fat-soluble vitamins and vitamin B12 Nitrogen Excretion = Converts ammonia to urea for excretion Bile Production = Facilitates digestion and absorption of fats Waste Management = Degrades old or damaged proteins</p> Signup and view all the answers

    Match the components of liver blood supply with their characteristics:

    <p>Arterial Blood = 25% of blood supply, O₂-rich Venous Blood = 75% of blood supply, nutrient-rich Hepatic Portal Vein = Carries blood from the digestive tract Hepatic Vein = Transports blood away from the liver</p> Signup and view all the answers

    Match the liver lobule components with their roles:

    <p>Portal Triad = Contains both the portal vein and hepatic artery Hepatic Arterioles = Supplies oxygenated blood to the lobule Portal Venules = Transports nutrient-rich blood to liver cells Central Vein = Collects blood from the lobule for drainage</p> Signup and view all the answers

    Match the liver's metabolic processes with their functions:

    <p>Iron Metabolism = Recycles iron from aged red blood cells Hormone Production = Secretes insulin and other hormones Albumin Production = Helps maintain osmotic pressure in blood Cholesterol Synthesis = Creates cholesterol for cell membranes</p> Signup and view all the answers

    Match the waste substances processed by the liver with their origins:

    <p>Pathogens = Taken from blood from the digestive tract Toxins = Includes drugs and alcohol Hormones = Circulate in the blood to be metabolized Nutrients = Derived from food processed in the intestines</p> Signup and view all the answers

    Match the liver functions with their primary outputs:

    <p>Vitamin Storage = Retained for bodily functions and metabolism Bile Production = Stored in the gallbladder for fat digestion Nitrogen Excretion = Excretes urea via the kidneys Protein Synthesis = Produces various plasma proteins</p> Signup and view all the answers

    Match the types of blood received by the liver with their sources:

    <p>Hepatic Portal Vein = Carries nutrient-rich blood from intestine Hepatic Artery = Delivers oxygenated blood from the heart Hepatic Vein = Drains blood away from the liver Portal Triad = Contains branches from both blood sources</p> Signup and view all the answers

    Match the liver's protective functions with their roles:

    <p>Detoxification = Processes harmful substances Immunological Function = Removes pathogens from blood Filtration = Cleanses blood via Kupffer cells Storage = Holds essential nutrients and vitamins</p> Signup and view all the answers

    Match the lipoproteins with their primary characteristics:

    <p>Chylomicrons = Transport dietary triglycerides VLDLs = Deliver triglycerides to tissues LDLs = Transport cholesterol to the liver HDLs = Transport cholesterol from tissues to the liver</p> Signup and view all the answers

    Match the metabolic processes with their descriptions related to lipid metabolism:

    <p>Triglyceride offloading = Conversion of VLDLs to smaller lipoproteins Atherosclerosis = Condition associated with high ApoB levels Cholesterol elimination = Conversion into bile acids Chylomicron remnants = Return to the liver after triglyceride offload</p> Signup and view all the answers

    Match the terms with their roles in the liver's functions:

    <p>ApoB = Linked to atherogenic processes Triglycerides = Stored energy source Cholesterol = Regulated by lipoproteins Bile acids = Facilitate cholesterol elimination</p> Signup and view all the answers

    Match the processes involved in lipid transportation with their respective sequences:

    <p>VLDL synthesis = Occurs in the liver IDL formation = Results from triglyceride offloading LDL transition = Final step after IDL Cholesterol transfer = From HDL to LDL</p> Signup and view all the answers

    Match the following liver functions with their respective descriptions:

    <p>Vitamin Storage = Storage of fat-soluble vitamins and vitamin B12 Bile Production = Production of bile for digestion Nitrogen Excretion = Conversion of ammonia into urea for excretion Hormones = Production of various hormones including IGF-1</p> Signup and view all the answers

    Match the substances with their corresponding locations of production or processing:

    <p>Chylomicrons = Intestines VLDLs = Liver LDLs = Circulation HDLs = Produced by liver and intestines</p> Signup and view all the answers

    Match the following lipoproteins with their primary function:

    <p>Chylomicrons = Transport dietary fats from the intestine LDL (Low-Density Lipoprotein) = Transport cholesterol to tissues HDL (High-Density Lipoprotein) = Transport cholesterol from tissues back to the liver VLDL (Very Low-Density Lipoprotein) = Transport triglycerides from the liver</p> Signup and view all the answers

    Match the following processes with their biological significance:

    <p>Nitrogen Excretion = Removes toxic ammonia from the body Lipid Transportation = Carries lipids in blood and extracellular fluids Iron Metabolism = Recycles iron from old red blood cells Hormone Production = Regulates various physiological processes in the body</p> Signup and view all the answers

    Match the types of lipoproteins with their functions:

    <p>Chylomicrons = Transport dietary fats from intestines VLDLs = Transport triglycerides from liver LDLs = Deliver cholesterol to cells HDLs = Remove excess cholesterol from cells</p> Signup and view all the answers

    Match the following cellular components with their role in lipid metabolism:

    <p>Enterocytes = Synthesize chylomicrons for lipid transport Kupffer Cells = Engage in breakdown of aged red blood cells Hepatocytes = Produce and secrete bile for fat digestion Adipocytes = Store and release fats for energy use</p> Signup and view all the answers

    Match each lipid-related term with its description:

    <p>Apolipoproteins = Protein components of lipoproteins Triglycerides = Main form of stored fat Lipoproteins = Complexes that transport lipids Bile acids = Facilitate digestion and absorption of fats</p> Signup and view all the answers

    Match the types of cholesterol movement with their pathways:

    <p>Transport to liver = Primary function of LDL Transfer from HDL = Process of exchanging cholesterol Delivery to tissues = Function of VLDLs Return to liver = Role of chylomicron remnants</p> Signup and view all the answers

    Match the following hormones with their source of production:

    <p>Angiotensinogen = Produced by the liver Thrombopoietin = Produced by the liver Insulin-like Growth Factor 1 (IGF-1) = Produced mainly in the liver Erythropoietin = Primarily produced by the kidneys</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Lipid-carrying vehicles = Complex particles that transport lipids Chylomicrons = Synthesized from dietary fats in enterocytes VLDL = Transport triglycerides from the liver to tissues LDL = Carries cholesterol to various organs</p> Signup and view all the answers

    Match the following liver activities with their specific process:

    <p>Degrading old proteins = Waste Management Converting fatty acids = Energy production in muscle cells Engagement of macrophages = Iron Metabolism Packaging lipids for transport = Lipid Transportation</p> Signup and view all the answers

    Match the following types of vitamins with their characteristics:

    <p>Fat-soluble Vitamins = Stored in liver and fatty tissues Water-soluble Vitamins = Not stored in the body; excess is excreted Vitamin B12 = Stored specifically in the liver Vitamin D = Can be synthesized in the skin</p> Signup and view all the answers

    Match the following components of circadian rhythms with their descriptions:

    <p>Suprachiasmatic Nucleus (SCN) = Central clock synchronizing peripheral clocks Circadian Oscillator = Negative feedback loops of gene expression Feeding Cycles = Control daily rhythms alongside circadian clocks Circadian Rhythm = Biological cycles occurring roughly every 24 hours</p> Signup and view all the answers

    Match the following aspects of circadian physiology to their effects:

    <p>Sleep/Wake Cycle = Regulated pattern of sleep and alertness Body Temperature = Fluctuates according to circadian rhythms Metabolism = Influenced by the timing of food intake GIT Rhythms = Includes cycles of bile secretion and gastric acid</p> Signup and view all the answers

    Match the researchers to their contributions in circadian rhythms studies:

    <p>Welsh et al., 2010 = Examined central clock dynamics Masri &amp; Sassone-Corsi = Investigated molecular circadian clocks Cohen et al. = Discussed feeding cycles' role in rhythms Doi et al. = Analyzed circadian rhythms in the GIT</p> Signup and view all the answers

    Match the following rhythmic physiology components to their corresponding functions:

    <p>Bile Secretion = Excretion into the gallbladder and duodenum Basal Gastric Acid Secretion = Regulates digestion processes Small Intestinal Motility = Facilitates nutrient absorption Liver Blood Flow = Influences metabolic activity and detoxification</p> Signup and view all the answers

    Match the following elements of the circadian clock to their roles:

    <p>Activator = Promotes gene expression in the feedback loop Repressor = Inhibits gene expression to maintain rhythm CCGs (Circadian Control Genes) = Key players in the molecular feedback loop Peripheral Tissue Clocks = Respond to signals from the SCN</p> Signup and view all the answers

    Match the following terms with their definitions related to circadian biology:

    <p>Circadian Clock = Biological process aligned with Earth's day-night cycle Intrinsic Clock = Biological timing device inherent to organisms Rhythmic Physiology = Physiological processes with regular cycles Feeding Patterns = Behavioral rhythms correlated with food intake</p> Signup and view all the answers

    Match the following types of rhythmic behaviors with their examples:

    <p>Circalunar Rhythms = Cycles based on lunar phases Circadian Rhythms = Daily sleep and wake patterns Ultradian Rhythms = Cycles shorter than 24 hours, e.g., heart rate Infradian Rhythms = Cycles longer than 24 hours, e.g., menstrual cycle</p> Signup and view all the answers

    Match the following outputs of circadian rhythms to their impacts on health:

    <p>Disruption of Sleep Patterns = Can lead to chronic health issues Irregular Feeding Cycles = Affects metabolic processes negatively Altered Body Temperature = May indicate circadian misalignment Changes in Gastric Activity = Influences digestive health significantly</p> Signup and view all the answers

    Chylomicron remnants become larger as they return to the liver for further processing.

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

    VLDLs produced by the liver are responsible for delivering triglycerides to muscle tissues.

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

    LDL molecules are primarily responsible for transporting glucose back to the liver.

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

    The liver plays no significant role in maintaining cholesterol homeostasis.

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

    As VLDLs continue to offload triglycerides, they are reclassified as IDLs before becoming LDLs.

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

    High levels of ApoB are linked to atherosclerosis.

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

    Cholesterol is eliminated from the body exclusively through urine.

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

    IDLs do not play a significant role in lipoprotein metabolism.

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

    The main component of plasma proteins synthesized by the liver is fibrinogen, which accounts for 60% of plasma proteins.

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

    Transferrin is a protein that binds to copper ions in the bloodstream.

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

    The liver detoxifies xenobiotics and produces Acetyl-CoA through the breakdown of fatty acids via β-oxidation.

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

    Glucose is stored as glycogen in the liver, and the process used to break it down for release into the bloodstream is termed glycolysis.

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

    Angiotensinogen, produced in the liver, plays a crucial role in regulating blood pressure and fluid balance.

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

    Plasminogen serves as a primary blood coagulation factor involved in the stimulation of platelet formation.

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

    Gluconeogenesis in the liver occurs when there is an excess of glucose available in the bloodstream.

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

    C-reactive peptide is an immune protein produced by the liver that increases in response to inflammation.

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

    The liver engages in the breakdown of aged red blood cells through Kupffer cells to recycle hemoglobin.

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

    Ammonia is converted to urea in the liver through the process known as gluconeogenesis.

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

    The liver synthesizes essential plasma proteins such as albumin and clotting factors.

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

    Cytochrome P450 enzymes in Phase II are responsible for the conjugation of polar molecules with toxins.

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

    Iron is transported in its ferrous form (Fe²⁺) in plasma bound to transferrin.

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

    Hepatocytes perform the entire detoxification process in a single phase.

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

    Phase III of detoxification primarily involves the active transport of conjugated metabolites out of the hepatocytes using membrane transport proteins.

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

    β-oxidation in the liver primarily breaks down fatty acids to produce Acetyl-CoA for energy.

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

    The liver produces albumin which is essential for transporting fat-soluble vitamins.

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

    Nitrogen excretion in the liver is achieved through the conversion of urea into ammonia.

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

    The primary source of iron for the liver is the uptake of dietary iron exclusively.

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

    Glucose is stored as glycogen in the liver and can be released into the bloodstream when needed.

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

    The liver detoxifies exogenous compounds exclusively through lysosomal digestion.

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

    Thrombopoietin produced by the liver is involved in the regulation of blood clot formation.

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

    Phase I detoxification primarily includes the secretion and excretion of harmful compounds.

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

    Albumin serves a critical role in the blood by facilitating nitrogen excretion as urea.

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

    The liver stores only water-soluble vitamins.

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

    Urinary excretion is the only pathway for drug elimination from the body in the detoxification process.

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

    The circadian clock plays no role in the timing of tolerability for anticancer drugs.

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

    Liver endothelial cells, also known as liver cell types, play a major role in drug detoxification.

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

    Phase II of detoxification typically involves increasing the water solubility of metabolic products through conjugation before excretion.

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

    Study Notes

    Liver Functions

    • Glucose Metabolism:
      • Releases glucose into the bloodstream to maintain normal levels.
      • Stores glucose as glycogen and breaks it down as needed (glycogenolysis).
      • Synthesizes glucose through gluconeogenesis during fasting or energy demand.
    • Lipid Metabolism:
      • Produces and distributes blood lipids (lipoproteins).
      • Breaks down fatty acids via β-oxidation, producing Acetyl-CoA for energy and biosynthesis.
    • Protein Synthesis:
      • Synthesizes various plasma proteins essential for blood functions (e.g., albumin, clotting factors).
    • Vitamin Storage:
      • Stores fat-soluble vitamins (A, D, E, K) and vitamin B12.
    • Bile Production:
      • Produces bile to aid in digestion and absorption of fats.
    • Nitrogen Excretion:
      • Converts ammonia, a byproduct of protein metabolism, into urea for excretion by the kidneys (urea cycle).
    • Waste Management:
      • Degrades old or damaged proteins.
      • Engages in the breakdown of aged red blood cells through Kupffer cells (macrophages).
    • Iron Metabolism:
      • Two sources of iron:
        • Uptake of dietary iron
        • Recycling of hemoglobin via Kupffer cells
      • DMT1 transports Fe²⁺ into the duodenal enterocyte.
      • Kupffer cells phagocytose senescent erythrocytes, releasing iron.
      • Fe²⁺ leaves the cells (duodenal enterocytes or macrophages) via ferroportin (FPN).
      • In the blood, Fe³⁺ binds to transferrin (Tf) in plasma.

    Lipoproteins

    • Complex particles essential for transport of lipids in blood or extracellular fluids (lipid-carrying vehicles).
    • Produced by the small intestine and liver.

    Chylomicrons

    • Originate and are synthesized in enterocytes.
    • Dietary fats and cholesterol, along with any cholesterol that returns to the intestine from the liver, get packaged into chylomicrons.
    • They then enter the lymphatic system and move into circulation, providing a significant source of energy, particularly for muscle cells.
    • Chylomicrons have a very short residence time in circulation (hours).

    Liver Blood Supply

    • The liver receives blood from two sources:
      • Arterial Blood (25%): Delivered via the hepatic artery, supplying O₂-rich blood.
      • Venous Blood (75%): Delivered via the hepatic portal vein, carrying blood from the digestive tract (e.g., stomach, small intestine, and large intestine). This blood contains:
        • Nutrients
        • Drugs
        • Hormones
        • Pathogens (e.g., bacteria, viruses)
        • Toxins
    • Blood leaves the liver through the hepatic vein.

    The Hepatic Portal Vein

    • Its primary role is to deliver nutrient-rich, but oxygen-poor blood to the liver.

    Liver Lobule: Structural and Functional Unit

    • The liver is organized into hexagonal units called liver lobules.
    • The portal vein and hepatic artery both branch extensively within the liver, supplying blood to the portal venules and hepatic arterioles, which converge at the corners of the lobule.

    Liver functions

    • Produces essential proteins for blood clotting and fluid balance (e.g., albumin)
    • Stores fat-soluble vitamins (A, D, E, K) and vitamin B12
    • Produces hormones (e.g., IGF-1, thrombopoietin, Angiotensinogen)
    • Produces bile
    • Excretes nitrogenous waste (urea) from protein metabolism
    • Degrades old or damaged proteins
    • Involved in iron metabolism
    • Degrades old red blood cells

    Liver Blood Supply

    • Receives blood from two sources:
      • Hepatic artery: Supplies oxygen-rich blood (25% of blood supply)
      • Hepatic portal vein: Carries nutrient-rich blood from the digestive tract, including drugs, hormones, pathogens, and toxins (75% of blood supply)
    • Blood leaves the liver via the hepatic vein

    Liver Lobule Structure

    • The liver is organized into hexagonal units called liver lobules
    • Each lobule consists of:
      • Portal triad at each corner:
        • Portal vein branch
        • Hepatic artery branch
        • Bile duct
      • Liver sinusoids: Shared capillary network where blood from the portal vein and hepatic artery mixes
      • Central vein: Collects blood from the sinusoids and drains into the hepatic vein
    • Hepatic vein: Empties filtered blood into the inferior vena cava (IVC)

    Liver Cell Types

    • Hepatocytes: Main functional cells; responsible for metabolism, detoxification, protein synthesis, and bile production
    • Liver Endothelial Cells (LEC): Line the blood vessels (sinusoids) and facilitate the exchange of substances between blood and hepatocytes
    • Stellate Cells: Store vitamin A and play a role in liver fibrosis when activated
    • Kupffer Cells: Specialized macrophages; phagocytize pathogens, senescent erythrocytes, dead cells, and debris

    Lipid Transportation

    • Lipoproteins: Complex particles that transport lipids in the blood or extracellular fluids (lipid-carrying vehicles)
    • Sites of lipoprotein synthesis: Small intestine (chylomicrons) and liver (VLDLs, HDLs, and LDLs)
    • Chylomicrons:
      • Synthesized in enterocytes
      • Transport dietary fats and cholesterol from the small intestine into the lymphatic system
      • Provide a significant source of energy for muscle cells
      • Become chylomicron remnants (smaller) after offloading triglycerides and return to the liver for processing
    • VLDLs:
      • Synthesized in the liver
      • Transport triglycerides to other tissues
      • Become smaller and are reclassified as IDLs as they offload triglycerides
    • IDLs: Eventually become LDL molecules
    • LDLs:
      • Primarily transport cholesterol back to the liver (via LDL receptor)
      • Transfer cholesterol from HDL particles
      • High ApoB levels are associated with atherosclerosis
    • Cholesterol: Eliminated through conversion into bile acids

    Liver and Blood Glucose Regulation

    • Plays a crucial role in maintaining blood glucose homeostasis
    • Regulates glucose storage (as glycogen), production (gluconeogenesis), and release
    • Responds to insulin and glucagon signals to adjust glucose levels

    Circadian Rhythms in the Liver

    • Liver functions are influenced by the circadian clock
    • Liver blood flow, bile secretion, and other metabolic processes exhibit diurnal rhythms
    • These rhythms contribute to the overall synchronization of metabolic processes throughout the body

    Liver Functions

    • Plasma Protein Synthesis:
      • Albumin: Maintains osmotic pressure and transports various substances in the blood.
      • Carriage Proteins: Transferrin (iron), Ceruloplasmin (copper), Transcortin (cortisol).
      • Blood Coagulation Factors: Fibrinogen, prothrombin, factors V, VII, IX, X, XI, XII, and protein C and S.
      • Anti-clotting Proteins: Plasminogen, antithrombin III.
      • (Pro-)Hormones: IGF-1, Thrombopoietin, Angiotensinogen.
      • Immune Proteins: Complement proteins, C-reactive peptide.
    • Blood Glucose Regulation:
      • Releases glucose into the bloodstream to maintain normal levels.
      • Stores glucose as glycogen and breaks it down when needed (glycogenolysis).
      • Synthesizes glucose through gluconeogenesis during fasting or energy demand.
    • Fat Metabolism:
      • Produces and distributes blood lipids (lipoproteins).
      • Breaks down fatty acids via β-oxidation, producing Acetyl-CoA for energy and biosynthesis.
    • Detoxification:
      • Metabolizes and detoxifies endogenous and exogenous compounds.
      • Xenobiotics (foreign chemicals) are processed in three phases:
        • Phase I: Modification: Cytochrome P450 enzymes add or expose functional groups to make molecules more hydrophilic and reactive.
        • Phase II: Conjugation: Functional groups are conjugated with polar molecules, increasing water solubility for excretion.
        • Phase III: Secretion/Excretion: Conjugated metabolites are transported out of the hepatocytes, mainly via the kidneys (urine) or into bile (feces).
    • Waste Management:
      • Degrades old or damaged proteins.
    • Vitamin Storage:
      • Stores fat-soluble vitamins (A, D, E, K) and vitamin B12.
    • Bile Production:
    • Nitrogen Excretion:
      • Converts ammonia, a byproduct of protein metabolism, into urea for excretion by the kidneys (urea cycle).

    Iron Metabolism

    • Iron Sources:
      • Dietary iron uptake.
      • Recycling of iron from senescent erythrocytes by Kupffer cells.
    • Iron Transport and Metabolism:
      • DMT1 transports Fe²⁺ into duodenal enterocytes.
      • Kupffer cells release iron after phagocytosing senescent red blood cells.
      • Fe²⁺ leaves cells via ferroportin (FPN).
      • In the blood, Fe³⁺ binds to transferrin (Tf).

    Lipid Transportation

    • Lipoprotein Synthesis: The liver is the second major site for lipoprotein synthesis. It can produce VLDLs (very-low-density lipoproteins).
    • VLDL Delivery: VLDLs are released into circulation and deliver triglycerides to other tissues.
    • IDL Formation: As VLDLs offload triglycerides, they become smaller and are reclassified as IDLs (intermediate-density lipoproteins).
    • LDL Formation: IDLs continue to shrink and become LDLs (low-density lipoproteins) which transport cholesterol back to the liver via LDL receptors.
    • HDL Interaction: LDLs can also transfer cholesterol from HDL (high-density lipoprotein) particles.
    • Cholesterol Elimination: Cholesterol is eliminated by converting it into bile acids.

    Hepatocytes - Detoxification

    • Hepatocytes: The primary cells responsible for biotransformation/detoxification of drugs and xenobiotics.
    • Drug Metabolism: Drugs and other xenobiotics are metabolized in three phases (see Detoxification above).

    Studying That Suits You

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

    Quiz Team

    Related Documents

    BIOM2012 GIT - Lecture 4 (1) PDF

    Description

    This quiz explores the various functions of the liver, including glucose metabolism, lipid metabolism, protein synthesis, and more. Understand how the liver plays a crucial role in maintaining bodily functions through its diverse metabolic processes.

    More Like This

    Glycogen
    10 questions

    Glycogen

    HallowedViolet avatar
    HallowedViolet
    Liver Functions and Metabolism
    33 questions

    Liver Functions and Metabolism

    ReputableClimax avatar
    ReputableClimax
    Liver Functions and Metabolism Quiz
    76 questions

    Liver Functions and Metabolism Quiz

    FormidablePennywhistle avatar
    FormidablePennywhistle
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser