Liver and Gallbladder Physiology
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Questions and Answers

What is the approximate weight range of the liver in an adult human?

  • 3.0 - 4.0 kg
  • 1.8 - 2.0 kg
  • 1.2 - 1.5 kg (correct)
  • 0.5 - 1.0 kg
  • Which lobe of the liver is located inferiorly?

  • Quadrate lobe (correct)
  • Right lobe
  • Left lobe
  • Caudate lobe
  • Which ligament is responsible for anchoring the liver to the diaphragm?

  • Falciform ligament
  • Umbilical ligament
  • Coronary ligament (correct)
  • Round ligament
  • Which of the following structures comprises up to 80% of the mononuclear phagocyte system within the liver?

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

    Which of these is NOT a lobe of the liver?

    <p>Inferior lobe</p> Signup and view all the answers

    What is the function of the gallbladder?

    <p>Bile concentration</p> Signup and view all the answers

    Which statement about the liver's vasculature is true?

    <p>It receives portal blood from multiple digestive organs.</p> Signup and view all the answers

    What role do Kupffer cells play in liver physiology?

    <p>They mediate immune responses.</p> Signup and view all the answers

    What is the primary function of hepatocytes in the liver?

    <p>To serve as the major functional cells of the liver</p> Signup and view all the answers

    Which structure separates the caudate lobe from the left lobe of the liver?

    <p>Ligamentum venosum</p> Signup and view all the answers

    Which component is NOT part of the hepatic lobule structure?

    <p>Hepatic stellate cell</p> Signup and view all the answers

    What is the primary source of deoxygenated blood entering the liver?

    <p>Hepatic portal vein</p> Signup and view all the answers

    What do hepatocytes secrete into bile canaliculi?

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

    Which of the following correctly identifies the contents of the portal triad?

    <p>Bile duct, arteriole branch of hepatic artery, venule branch of portal vein</p> Signup and view all the answers

    What role do Kupffer cells play in the liver?

    <p>They act as macrophages</p> Signup and view all the answers

    Which structure primarily drains the hepatic sinusoids?

    <p>Central vein</p> Signup and view all the answers

    What is the process called when bile acids are dehydroxylated by bacteria in the terminal ileum and colon?

    <p>Entrohepatic circulation</p> Signup and view all the answers

    Which component of bile is responsible for inhibiting bacterial growth?

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

    Which of the following substances is NOT a component of bile?

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

    What is the initial substance from which bile acids are synthesized in the liver?

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

    In which part of the bile flow pathway does bile begin its movement from hepatocytes?

    <p>Bile canaliculi</p> Signup and view all the answers

    What process involves the addition of glucuronate, sulfate, or glutathione to compounds?

    <p>Phase II biotransformation</p> Signup and view all the answers

    Which enzyme is responsible for adding glucuronic acid during bilirubin conjugation?

    <p>Uridine diphosphate glucuronosyltransferase (UGT)</p> Signup and view all the answers

    Where is uridine diphosphate glucuronosyltransferase (UGT) located within the cell?

    <p>Smooth endoplasmic reticulum</p> Signup and view all the answers

    What is the primary role of ATP-binding cassette (ABC) transporters?

    <p>To transport conjugated drugs and bilirubin</p> Signup and view all the answers

    Which of the following compounds is unconjugated before reaching the liver?

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

    The secretion of conjugated bilirubin into bile occurs across which type of membrane?

    <p>Canalicular membrane</p> Signup and view all the answers

    Which enzyme catalyzes the sulfation of compounds?

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

    What component is added to bilirubin during its conjugation process in the liver?

    <p>One or two residues of glucuronic acid</p> Signup and view all the answers

    What is the most mobile part of the large intestine?

    <p>Sigmoid colon</p> Signup and view all the answers

    Which of the following mechanisms predominantly drives water absorption in the large intestine?

    <p>Electrogenic sodium absorption</p> Signup and view all the answers

    The rectum is innervated primarily by which type of nerves?

    <p>Pelvic splanchnic nerves</p> Signup and view all the answers

    Which part of the large intestine is the widest and most prone to perforation?

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

    What is the main histological feature of the mucosa in the large intestine?

    <p>Deep intestinal crypts</p> Signup and view all the answers

    Which type of movement in the large intestine aids in the expulsion of feces into the rectum?

    <p>Mass action contractions</p> Signup and view all the answers

    What type of epithelium transitions in the anal canal?

    <p>Simple columnar to stratified squamous</p> Signup and view all the answers

    Which of the following conditions results from the absence of ganglions in the distal colon?

    <p>Hirschsprung Disease</p> Signup and view all the answers

    Which area of the large intestine has the highest absorption capacity?

    <p>Ascending colon</p> Signup and view all the answers

    Which of the following reflexes is characterized by large waves of peristalsis following food intake?

    <p>Gastrocolic reflex</p> Signup and view all the answers

    The function of mucin in the large intestine is primarily to:

    <p>Serve as a barrier for pathogens</p> Signup and view all the answers

    What is a major contributing factor to the onset of Irritable Bowel Syndrome (IBS)?

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

    Which component is essential for voluntary control during defecation?

    <p>Pudendal nerve</p> Signup and view all the answers

    What percentage of body weight does the liver constitute in an adult human?

    <p>2-5%</p> Signup and view all the answers

    Which ligament is primarily responsible for separating the right and left lobes of the liver?

    <p>Falciform ligament</p> Signup and view all the answers

    Which lobe of the liver is considered non-palpable?

    <p>Caudate lobe</p> Signup and view all the answers

    What role do Kupffer cells primarily play within the liver?

    <p>Immunological defense</p> Signup and view all the answers

    Which structure is described as being located posteriorly in the liver anatomy?

    <p>Caudate lobe</p> Signup and view all the answers

    Which function is NOT associated with the liver?

    <p>Filtration of toxins from the lymph</p> Signup and view all the answers

    The round ligament of the liver is a remnant of which structure?

    <p>Left umbilical vein</p> Signup and view all the answers

    What is the role of the hepatic portal system in relation to the liver?

    <p>It brings nutrient-rich blood to the liver.</p> Signup and view all the answers

    What is the main pathophysiological mechanism leading to the formation of pigment stones in cholelithiasis?

    <p>Excessive bilirubin production</p> Signup and view all the answers

    Which symptom is commonly associated with acute cholecystitis due to gallstone obstruction?

    <p>Progressive right upper quadrant pain</p> Signup and view all the answers

    Which of the following is NOT a pre-hepatic cause of jaundice?

    <p>Genetic deficiency of UGTIAI activity</p> Signup and view all the answers

    What complication can occur if a large gallstone erodes into an adjacent loop of small bowel?

    <p>Intestinal obstruction</p> Signup and view all the answers

    Which combination of symptoms is frequently associated with acute cholecystitis?

    <p>Fever, nausea, and vomiting</p> Signup and view all the answers

    In jaundice, what does the term 'icterus' refer to?

    <p>Yellow discoloration of the sclera</p> Signup and view all the answers

    Which factor is not involved in the pathogenesis of pigment stones?

    <p>Excessive cholesterol secretion</p> Signup and view all the answers

    What is a common clinical feature of biliary pain caused by obstructive cholelithiasis?

    <p>Excruciating and spasmodic pain in the right upper quadrant</p> Signup and view all the answers

    What structure primarily separates the caudate lobe from the left lobe of the liver?

    <p>Ligamentum venosum</p> Signup and view all the answers

    Which of the following best describes the role of the hepatic portal vein?

    <p>Transports deoxygenated, nutrient-rich blood to the liver</p> Signup and view all the answers

    Which cell type comprises around 80% of the liver's volume?

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

    What structures border the hepatic laminae formed by hepatocytes?

    <p>Bile canaliculi</p> Signup and view all the answers

    What forms the critical component of the portal triad?

    <p>Bile duct</p> Signup and view all the answers

    The hepatic lobules surround which structure?

    <p>Central vein</p> Signup and view all the answers

    What type of arrangement do hepatocytes have within the liver?

    <p>Hepatic laminae</p> Signup and view all the answers

    Which of the following components is NOT found within a hepatic lobule?

    <p>Central canal</p> Signup and view all the answers

    What is the primary structural characteristic of the gallbladder's mucosa?

    <p>Simple columnar epithelium</p> Signup and view all the answers

    Which statement regarding the gallbladder's function is accurate?

    <p>It stores bile until needed in the duodenum.</p> Signup and view all the answers

    What type of muscle is present in the gallbladder's muscularis layer?

    <p>Smooth muscle oriented in various directions</p> Signup and view all the answers

    What is the approximate capacity of the gallbladder in adults?

    <p>30-50 mL</p> Signup and view all the answers

    Which component of the gallbladder's anatomy aids in its absorptive surface?

    <p>Prominent folds in the epithelium</p> Signup and view all the answers

    What characterizes the abdominal pain associated with acute pancreatitis?

    <p>It is constant, intense, and often referred to the back.</p> Signup and view all the answers

    Which of the following statements is true regarding chronic pancreatitis?

    <p>Alcohol abuse is a common contributing factor.</p> Signup and view all the answers

    What is the primary pathological finding in chronic pancreatitis?

    <p>Fibrosis of pancreatic tissue.</p> Signup and view all the answers

    What is the mechanism of saponification observed in fat necrosis during pancreatitis?

    <p>Free pancreatic lipases cleaving triglycerides into fatty acids that bind with calcium.</p> Signup and view all the answers

    In which condition does fat necrosis occur?

    <p>In both mild and severe pancreatitis injuries.</p> Signup and view all the answers

    What is a major complication associated with severe acute pancreatitis?

    <p>Pseudocysts and potential for shock.</p> Signup and view all the answers

    The presence of which factor can indicate a poor prognosis in acute pancreatitis?

    <p>Hypocalcemia resulting from saponification.</p> Signup and view all the answers

    Which of the following best describes a pseudocyst?

    <p>A localized necrotic collection without epithelial lining.</p> Signup and view all the answers

    What is the primary cause of ductal obstruction in chronic pancreatitis?

    <p>Formation of plugs due to increased protein concentration.</p> Signup and view all the answers

    What condition is characterized by repeated mild to moderate abdominal pain over an extended period?

    <p>Chronic pancreatitis.</p> Signup and view all the answers

    What is the process by which secondary bile salts are formed in the terminal ileum and colon?

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

    Which of the following components is NOT typically found in bile?

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

    Which protein secreted by the liver has a role in inhibiting the growth of bacteria in bile?

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

    Which structure does bile enter immediately after the bile canaliculi?

    <p>Bile ductules</p> Signup and view all the answers

    What are the primary substances bile acids are synthesized from in the liver?

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

    What happens to conjugated bilirubin in the terminal ileum and colon?

    <p>It is converted into urobilinogen, some of which becomes stercobilin.</p> Signup and view all the answers

    Which of the following substances is NOT synthesized by the liver?

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

    What is one function of bile production by the liver?

    <p>Elimination of waste products such as bilirubin and cholesterol</p> Signup and view all the answers

    Which nutrient transport mechanism does the liver NOT utilize for substrates received via the hepatic portal vein?

    <p>Enzyme-mediated degradation before release</p> Signup and view all the answers

    After conversion in the liver, how does urobilinogen predominantly exit the body?

    <p>Through filtration by the kidney into urine</p> Signup and view all the answers

    What is the primary catalytic activity performed by uridine diphosphate glucuronosyltransferase (UGT)?

    <p>Addition of glucuronic acid</p> Signup and view all the answers

    Which transport mechanism is utilized by ABC transporters in the liver?

    <p>Active transport for various conjugated drugs</p> Signup and view all the answers

    During bilirubin conjugation, how many residues of glucuronic acid are typically added?

    <p>One to two</p> Signup and view all the answers

    What cellular location is primarily associated with the activity of sulfotransferases?

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

    What is the primary purpose of phase III in the context of biotransformation?

    <p>Transport of conjugated compounds out of hepatocytes</p> Signup and view all the answers

    What happens to unconjugated bilirubin after being transported to the liver attached to albumin?

    <p>It undergoes conjugation with glucuronic acid</p> Signup and view all the answers

    Which component does NOT participate in the conjugation process during Phase II metabolism?

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

    What type of membrane transport occurs for the secretion of conjugated bilirubin into bile?

    <p>Active transport via specific transporters</p> Signup and view all the answers

    What is a common complication associated with the progression of cirrhosis?

    <p>Hepatic encephalopathy</p> Signup and view all the answers

    What is a significant risk factor specifically associated with cholesterol gallstone formation?

    <p>Rapid weight loss</p> Signup and view all the answers

    Which process promotes the activation of stellate cells in liver cirrhosis?

    <p>Signals from platelet-derived growth factor</p> Signup and view all the answers

    Which of the following is NOT a symptom commonly associated with cirrhosis in its advanced stages?

    <p>Extreme muscle gain</p> Signup and view all the answers

    What leads to the aggregation of cholesterol crystals in the formation of cholesterol gallstones?

    <p>Mucus trapping of nucleated crystals</p> Signup and view all the answers

    What usually happens to areas of hepatocyte loss during cirrhosis?

    <p>They create regenerative nodules</p> Signup and view all the answers

    Which type of gallstone primarily consists of bilirubin salts?

    <p>Pigment stones</p> Signup and view all the answers

    What is a factor that contributes to the supersaturation of bile, leading to cholesterol gallstone formation?

    <p>Hypomotility of the gallbladder</p> Signup and view all the answers

    Which part of the large intestine is most likely to become obstructed due to twisting?

    <p>Sigmoid colon</p> Signup and view all the answers

    What type of epithelial cells are primarily found in the mucosa of the large intestine?

    <p>Simple columnar cells</p> Signup and view all the answers

    Which artery supplies the proximal portion of the rectum?

    <p>Superior rectal artery</p> Signup and view all the answers

    During defecation, which muscle is responsible for involuntarily relaxing?

    <p>Internal anal sphincter</p> Signup and view all the answers

    The presence of which substance in the large intestine is primarily responsible for water absorption?

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

    What mechanism predominantly drives the absorption of sodium in the large intestine?

    <p>Electroneutral NaCl absorption</p> Signup and view all the answers

    In the context of the large intestine, what is the primary function of mucin?

    <p>Attract water and lubricate</p> Signup and view all the answers

    What reflex is characterized by the relaxation of the ileocecal valve?

    <p>Gastroileal reflex</p> Signup and view all the answers

    Which of the following is NOT a cause of Irritable Bowel Syndrome (IBS)?

    <p>Excessive water consumption</p> Signup and view all the answers

    Which of the following is a characteristic histological feature of the large intestine?

    <p>High density of goblet cells</p> Signup and view all the answers

    What is the primary source of the blood supply to the sigmoid colon?

    <p>Sigmoid branches of the inferior mesenteric artery</p> Signup and view all the answers

    Which condition is characterized by the absence of ganglions in the distal colon?

    <p>Hirschsprung Disease</p> Signup and view all the answers

    Which type of nerve innervates the external anal sphincter?

    <p>Pudendal nerve</p> Signup and view all the answers

    Which part of large intestine has the least ability to absorb fluids?

    <p>Descending colon</p> Signup and view all the answers

    What is the primary outcome of Phase I biotransformation reactions?

    <p>Insertion of an oxygen atom into the substrate</p> Signup and view all the answers

    Which of the following statements best describes the function of P-450 cytochromes in biotransformation?

    <p>They facilitate oxidation or reduction reactions of lipophilic compounds.</p> Signup and view all the answers

    How does the addition of a highly hydrophilic compound during Phase II biotransformation affect a drug?

    <p>It prepares the drug for renal excretion.</p> Signup and view all the answers

    What role does Hypericum perforatum play in the function of P-450 cytochromes?

    <p>It induces the activity of certain CYP450 enzymes.</p> Signup and view all the answers

    Which of the following processes is NOT typically associated with Phase I biotransformation?

    <p>Conjugation with amino acids</p> Signup and view all the answers

    What is the primary function of uridine diphosphate glucuronosyltransferase (UGT) in the liver?

    <p>Adding glucuronic acid to unconjugated bilirubin</p> Signup and view all the answers

    Which of the following statements correctly describes the function of sulfontransferases?

    <p>They facilitate the sulfation of compounds</p> Signup and view all the answers

    In which cellular location are glutathione-S-transferases primarily found?

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

    What role do ATP-binding cassette (ABC) transporters play in the liver?

    <p>They transport conjugated drugs and bilirubin out of the hepatocyte</p> Signup and view all the answers

    What happens to unconjugated bilirubin after it is formed from the degradation of heme?

    <p>It binds to albumin and is transported to the liver</p> Signup and view all the answers

    Which of the following accurately describes phase III of biotransformation?

    <p>Refers to the excretion of conjugated compounds from hepatocytes</p> Signup and view all the answers

    How many residues of glucuronic acid are typically added to bilirubin during conjugation in the liver?

    <p>One to two residues</p> Signup and view all the answers

    What is a characteristic feature of the transport mechanisms used for conjugated compounds in the liver?

    <p>They require specific transport proteins</p> Signup and view all the answers

    Which factor is primarily responsible for stimulating differentiation in hepatic stellate cells?

    <p>Platelet-derived growth factor –Beta (PDGF-B) receptor</p> Signup and view all the answers

    What is the primary cause of the formation of cholesterol gallstones?

    <p>Nucleation of solid cholesterol monohydrate crystals</p> Signup and view all the answers

    Which of the following is a common symptom experienced in the advanced stages of cirrhosis?

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

    What processes contribute to the progression of liver cirrhosis?

    <p>Loss of sinusoidal endothelial cells and stellate cell activation</p> Signup and view all the answers

    Which type of stones are formed from bilirubin calcium salts?

    <p>Pigment stones</p> Signup and view all the answers

    What is a significant risk factor for the development of cholelithiasis?

    <p>Increased estrogen exposure</p> Signup and view all the answers

    What complication is most commonly associated with hepatic encephalopathy?

    <p>Cognitive impairment</p> Signup and view all the answers

    Which of the following statements regarding the pathogenesis of cholesterol stones is correct?

    <p>Gallbladder hypomotility contributes to stone formation</p> Signup and view all the answers

    What is the major risk factor associated with 80% of acute pancreatitis cases?

    <p>Excessive alcohol intake</p> Signup and view all the answers

    Which ligament is responsible for separating the left lobe and quadrate lobe of the liver?

    <p>Round ligament</p> Signup and view all the answers

    Which of the following genetic mutations is particularly notable in the context of acute pancreatitis?

    <p>Mutations in the trypsinogen (PRSS1) gene</p> Signup and view all the answers

    What proportion of individuals with gallstones are likely to experience an episode of acute pancreatitis?

    <p>5%</p> Signup and view all the answers

    What is the primary pathological feature of acute pancreatitis?

    <p>Acute reversible pancreatic injury</p> Signup and view all the answers

    Which ligament attaches the liver to the diaphragm?

    <p>Coronary ligament</p> Signup and view all the answers

    What is the primary stimulating hormone for the secretion of inactive pancreatic enzymes by acinar cells?

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

    What component of pancreatic secretions creates osmotic pressure that causes water to move into the ducts?

    <p>Bicarbonate ions</p> Signup and view all the answers

    Which part of the pancreas experiences arterial supply primarily from the splenic artery?

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

    Which pancreatic secretion is stimulated by secretin in response to acidic chyme entering the duodenum?

    <p>Bicarbonate-rich fluid</p> Signup and view all the answers

    What is the function of centroacinar cells in the pancreas?

    <p>Secretion of bicarbonate-rich fluid</p> Signup and view all the answers

    Which pancreatic enzyme is activated in the duodenum by entero-kinase?

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

    What describes the pancreas in terms of its anatomical location?

    <p>Retroperitoneal structure</p> Signup and view all the answers

    Which phase of pancreatic secretion is primarily influenced by hormonal signals from the duodenum?

    <p>Intestinal phase</p> Signup and view all the answers

    Which hormone is released when fatty acids and proteins stimulate the I cells in the duodenum?

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

    What physiological condition can arise from the rupture of pancreatic pseudocysts?

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

    Which type of pancreatic cell primarily produces digestive enzymes?

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

    Which of the following enzymes is classified as an exopeptidase?

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

    What is the general function of acinar cells in the pancreas?

    <p>Secretion of inactive pancreatic enzymes</p> Signup and view all the answers

    Which of the following processes is NOT a characteristic of trypsin's regulation?

    <p>It is secreted in its active form directly into the duodenum.</p> Signup and view all the answers

    What is the primary function of organic cation transporters (OCT) in the body?

    <p>Facilitate the uptake of lipophilic organic cations</p> Signup and view all the answers

    What is the primary function of the ligamentum venosum in the liver?

    <p>Separate the caudate and left lobe</p> Signup and view all the answers

    Which Phase I reaction involves the introduction of oxygen into a substrate?

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

    What effect does Hypericum perforatum have on CYP450 enzymes?

    <p>Inducer of CYP450 activity</p> Signup and view all the answers

    Which component of the hepatic lobule surrounds the central vein?

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

    What is the outcome of Phase II biotransformation?

    <p>Addition of highly hydrophilic substances</p> Signup and view all the answers

    What type of blood does the hepatic artery supply to the liver?

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

    Which cells make up approximately 80% of the liver's volume?

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

    Which reaction type is NOT typically part of Phase I biotransformation?

    <p>Conjugation with glucuronate</p> Signup and view all the answers

    What structures are included in the portal triad of a hepatic lobule?

    <p>Bile duct, hepatic artery, portal vein</p> Signup and view all the answers

    Which of the following statements correctly identifies the function of hepatic sinusoids?

    <p>Facilitate nutrient exchange with blood</p> Signup and view all the answers

    What type of cells serve as the immune component within the liver?

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

    Which structure represents the opening for the hepatic artery, portal vein, and common hepatic duct into the liver?

    <p>Porta hepatis</p> Signup and view all the answers

    What structural feature of the gallbladder enhances its absorptive surface?

    <p>Numerous prominent folds</p> Signup and view all the answers

    Which component of the gallbladder is responsible for the storage and concentration of bile?

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

    Which of the following statements accurately describes the lamina propria of the gallbladder?

    <p>Rich in elastic and collagen fibers</p> Signup and view all the answers

    What is the primary function of the gallbladder in relation to bile?

    <p>Storage and concentration of bile</p> Signup and view all the answers

    Which histological property of the gallbladder's epithelium is critical for its function?

    <p>Simple columnar epithelium with microvilli</p> Signup and view all the answers

    What is a common cause of acute pancreatitis?

    <p>Excessive alcohol intake</p> Signup and view all the answers

    Which ligaments separate the liver lobes?

    <p>Round ligament</p> Signup and view all the answers

    What is a major risk factor for developing acute pancreatitis?

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

    Which of the following genetic mutations is associated with acute pancreatitis?

    <p>Mutations in trypsinogen (PRSS1)</p> Signup and view all the answers

    Which symptom is typically associated with acute pancreatitis?

    <p>Mild to moderate abdominal pain</p> Signup and view all the answers

    What primary anatomical structure separates the quadrate lobe from the left lobe of the liver?

    <p>Round ligament</p> Signup and view all the answers

    Which metabolic condition is a causative factor for acute pancreatitis?

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

    Which part of the large intestine is the most mobile?

    <p>Sigmoid colon</p> Signup and view all the answers

    What is the primary function of the large intestine?

    <p>Conversion of undigested material into feces</p> Signup and view all the answers

    Which condition can result from the absence of ganglions in the myenteric and submucosal plexuses in the distal colon?

    <p>Hirschsprung Disease</p> Signup and view all the answers

    What reflex is characterized by the relaxation of the ileocecal valve due to food leaving the stomach?

    <p>Gastroileal reflex</p> Signup and view all the answers

    What type of muscle makes up the internal anal sphincter?

    <p>Smooth muscle</p> Signup and view all the answers

    Which of the following vessels does NOT supply the large intestine?

    <p>Celiac trunk</p> Signup and view all the answers

    What type of epithelium is found at the transition of the anal canal?

    <p>Stratified squamous epithelium</p> Signup and view all the answers

    Which of the following components is responsible for maintaining fecal continence?

    <p>Puborectalis muscle</p> Signup and view all the answers

    What is the main histological feature of the mucosa in the large intestine?

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

    Which type of contraction is primarily involved in the expulsion of feces during defecation?

    <p>Peristaltic contraction</p> Signup and view all the answers

    Which of the following factors is primarily responsible for driving water absorption in the large intestine?

    <p>Electrochemical gradient of sodium</p> Signup and view all the answers

    Which part of the large intestine is most prone to perforation?

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

    What is a common clinical feature of Inflammatory Bowel Disease (IBD)?

    <p>Mucosal inflammation</p> Signup and view all the answers

    Which of the following movements is NOT a type of motility associated with the large intestine?

    <p>Cardiac contraction</p> Signup and view all the answers

    Study Notes

    Liver and Gallbladder Physiology

    • The liver is a large organ weighing approximately 1.2 - 1.5 kg, constituting 2-5% of adult body weight.
    • It receives portal blood from the stomach, intestines, and spleen, playing a crucial role in metabolism and immunology.
    • Kupffer cells, residing in the liver, account for up to 80% of the mononuclear phagocyte system.

    Liver Anatomy

    • Comprised of four lobes: right, left, quadrate (inferior), and caudate (posterior and non-palpable).
    • Key ligaments include:
      • Coronary ligament: connects liver to diaphragm.
      • Falciform ligament: separates right and left lobes.
      • Round ligament: remnant of the left umbilical vein.

    Liver Vasculature

    • Receives dual blood supply:
      • Hepatic artery: oxygenated blood.
      • Hepatic portal vein: deoxygenated, nutrient-rich blood.
    • Both blood sources enter through the porta hepatis along with the common hepatic duct.

    Liver Histology

    • Composed primarily of hepatocytes, bile canaliculi, and hepatic sinusoids.
    • Hepatocytes are the main functional cells, making up 80% of the liver’s volume.

    Liver Functions

    • Biotransformation of drugs includes phases of conjugation, with conjugated compounds transported out of hepatocytes into bile or blood.
    • Bilirubin conjugation involves adding glucuronic acid, which is then excreted into bile.
    • Bile, produced from cholesterol, aids in lipid digestion and comprises bile salts, phospholipids, immunoglobulin A (IgA), waste products, and trace minerals.

    Gallbladder Physiology

    • Functions in bile concentration.
    • Receives bile from the liver and modifies its composition.

    Liver Pathology

    • Common pathologies include:
      • Cirrhosis: chronic liver disease leading to fibrosis and impaired liver function.
      • Cholelithiasis: presence of gallstones in the gallbladder.
      • Jaundice: yellowing of skin and eyes due to elevated bilirubin levels.

    Large Intestine Overview

    • Converts undigested material into feces, stores and transports feces, with a significant microbial presence that produces Vitamin K and Biotin.
    • Slow motility allows for absorption of water and electrolytes.

    Large Intestine Anatomy

    • Extends from the ileocecal valve to the anus, including cecum, ascending colon, transverse colon, descending colon, and sigmoid colon.
    • Rectum is separated from surrounding structures by Denonvilliers’ fascia.

    Rectum and Anal Canal

    • The rectum is approximately 12-15 cm long, innervated by pelvic splanchnic nerves.
    • Anal canal measures about 4 cm and contains internal (involuntary) and external (voluntary) anal sphincters.

    Vasculature of the Large Intestine

    • Supplied by the superior mesenteric and inferior mesenteric arteries, which branch into various arteries supplying specific colon segments.
    • Venous drainage mirrors the arterial supply structure.

    Innervation of the Large Intestine

    • Sympathetic innervation arises from thoracic and lumbar spinal nerves.
    • Parasympathetic input is from the vagus nerve for the proximal colon and sacral nerve roots for the distal colon.

    Large Intestine Histology

    • Characterized by simple columnar epithelium with abundant goblet cells and deep crypts for secretion.
    • Teniae coli are three longitudinal bands of smooth muscle.

    Digestion and Absorption in the Large Intestine

    • Microbiota facilitate digestion, primarily absorbing water and minerals.
    • Mucin secreted to form a protective mucus layer aiding in lubrication and immune function.

    Motility and Fluid Homeostasis

    • Through segmentation, peristalsis, and mass action contractions, feces are moved towards the rectum.
    • Absorbs around 5 liters of water per day, primarily influenced by sodium absorption.

    Defecation Mechanism

    • Rectum distension triggers reflex contractions, and internal anal sphincter relaxes involuntarily.
    • Voluntary defecation involves external anal sphincter control and abdominal muscle contractions.

    Diseases of the Large Intestine

    • Irritable Bowel Syndrome (IBS): affects 9-23% of the global population, commonly emerging in adolescence.
    • Other diseases include Inflammatory Bowel Disease (IBD), Diverticular Disease, and Hemorrhoids.

    Liver and Gallbladder: Physiology and Pathology

    • Liver weighs approximately 1.2 - 1.5 kg, constituting 2-5% of adult body weight.
    • Functions as a vital part of the circulatory system, receiving portal blood from the gastrointestinal tract.
    • Kupffer cells in the liver represent about 80% of the mononuclear phagocyte system, playing a crucial role in immunology.

    Liver Anatomy

    • Comprises four lobes: right, left, quadrate (inferiorly located), and caudate (posteriorly located and non-palpable).
    • Key ligaments include the coronary (anchors liver to diaphragm), falciform (separates lobes), round ligament (remnant of the left umbilical vein), and ligamentum venosum (separates caudate and left lobe).

    Liver Vasculature

    • Receives blood from two sources: oxygenated blood via the hepatic artery and deoxygenated nutrient-rich blood via the hepatic portal vein.
    • Porta hepatis is the key entry point for the hepatic artery, portal vein, and common hepatic duct.

    Liver Histology

    • Major components include hepatocytes, bile canaliculi/cholangiocytes, and hepatic sinusoids.
    • Hepatocytes, the primary functional cells, make up 80% of liver volume and are organized into hepatic laminae.

    Gallbladder Anatomy and Histology

    • Gallbladder is about 10 cm long and 4 cm in cross-section, storing 30-50 mL of bile.
    • Its mucosa features simple columnar epithelium, elastic and collagen fibers in the lamina propria, thin muscularis, and serosa with simple squamous epithelium.

    Gallbladder Function

    • The gallbladder stores bile secreted by hepatocytes, concentrating it through the reabsorption of Na, Cl, and water until needed in the duodenum.

    Liver and Gallbladder Pathology

    • Cirrhosis: chronic liver disease characterized by scarring and liver dysfunction.
    • Cholelithiasis: formation of gallstones, often due to excessive bilirubin or infection of the gallbladder.
    • Jaundice: yellow discoloration due to elevated bilirubin levels, classified into pre-hepatic, intra-hepatic, and post-hepatic causes.

    Cholelithiasis

    • Characterized by biliary pain, which can be constant or “colicky,” often associated with gallbladder inflammation (cholecystitis).
    • Complications may lead to acute cholecystitis or increased risk of gallbladder carcinoma.

    Jaundice Causes

    • Pre-hepatic: Hemolytic anemias and blood resorption from internal hemorrhage.
    • Intra-hepatic: Issues with bilirubin conjugation or liver disease leading to reduced hepatocyte function.
    • Post-hepatic: Bile duct obstruction causes decreased excretion.

    Acute Pancreatitis

    • Primary symptom: intense abdominal pain, often referred to the back, accompanied by nausea and anorexia.
    • Can escalate to systemic inflammation and medical emergencies like shock and kidney failure.

    Chronic Pancreatitis

    • Irreversible destruction of pancreatic tissue following recurrent acute episodes, often due to alcohol abuse.
    • Results in abdominal pain, pancreatic insufficiency, and a high mortality rate due to malabsorption and diabetes.

    Pseudocysts

    • Localized collections of necrotic-hemorrhagic fluid rich in pancreatic enzymes, typically arising post-acute pancreatitis.
    • Formed by encapsulated fat necrosis and often found within or adjacent to the pancreas.

    Clinical Features of Pseudocysts

    • Symptoms correlate with the underlying condition and can manifest as abdominal pain or discomfort.

    Drug Metabolism

    • Phase II metabolism typically involves conjugation using glucuronate, sulfate, or glutathione.
    • Uridine diphosphate glucuronosyltransferase (UGT) catalyzes the addition of glucuronic acid, located in the smooth endoplasmic reticulum (ER).
    • Sulfotransferases and glutathione S-transferases facilitate sulfation and the addition of glutathione in the cytosol.
    • Conjugated compounds exit hepatocytes in what is referred to as phase III biotransformation.

    Bilirubin Conjugation

    • Senescent erythrocytes are processed by macrophages, leading to the degradation of heme into bilirubin.
    • Unconjugated bilirubin binds to albumin and transports to the liver, where 1-2 glucuronic acid residues are added for conjugation.
    • Conjugated bilirubin is excreted as bilirubin glucuronide into bile.
    • Gut bacteria convert some conjugated bilirubin back into bilirubin, which is then transformed into urobilinogen; part gets excreted as stercobilin, contributing to fecal color.

    Liver Functions

    • The liver serves as a metabolic hub where absorbed nutrients from the hepatic portal vein can be stored, released, or synthesized.
    • It synthesizes essential substances like albumin, coagulation factors, and plasma proteins.
    • Primary functions of bile production include waste elimination (e.g., bilirubin, cholesterol) and aiding in lipid digestion and absorption.

    Bile Production

    • Bile is synthesized from cholesterol, creating primary bile acids, which are then conjugated to form bile salts.
    • Enterohepatic circulation allows bile acids to be dehydroxylated by bacteria and reabsorbed in the ileum and colon.
    • Bile consists of various components such as phospholipids, Immunoglobulin A (IgA), cholesterol, and bile pigments.

    Cirrhosis: Pathogenesis and Complications

    • Activation of stellate cells leads to extracellular matrix deposition, loss of sinusoidal endothelial cells, and formation of fibrous septa from hepatocyte loss.
    • Advanced cirrhosis may be asymptomatic until severe progressions occur, leading to nonspecific symptoms such as anorexia and weakness.
    • Complications include liver failure, jaundice, hepatic encephalopathy, and a high risk of hepatocellular carcinoma.

    Cholelithiasis (Gallstones)

    • Gallstones are a common biliary tract disease, affecting 10-20% of adults in wealthier nations.
    • Two main types are cholesterol stones (from crystalline cholesterol monohydrate) and pigment stones (from bilirubin calcium salts).
    • Risk factors vary by type and include age, sex, obesity, and rapid weight loss.

    Large Intestine Overview

    • The large intestine converts undigested material into feces by absorbing water and adding mucus, and it harbors a high microbial presence.
    • It plays a crucial role in synthesizing vitamins (e.g., Vitamin K and Biotin) and exhibits slower motility for optimal absorption of water and solutes.

    Large Intestine Anatomy

    • The large intestine begins at the ileocecal valve and ends at the anus, featuring sections such as the cecum, ascending colon, transverse colon, descending colon, and sigmoid colon.
    • The sigmoid colon is particularly mobile and susceptible to volvulus.

    Rectum and Anal Canal

    • The rectum is 12-15 cm long and has a supportive fascial structure to prevent rectocele.
    • The anal canal is 4 cm long and transitions from simple columnar to stratified squamous epithelium; includes both internal (involuntary) and external (voluntary) anal sphincters.

    Vasculature and Innervation

    • Supplies oxygenated blood through the superior mesenteric artery and inferior mesenteric artery, with venous drainage corresponding to the arterial supply.
    • Sympathetic and parasympathetic innervation regulates functions, with vagus nerve involvement in the upper colon and pelvic splanchnic nerves in the lower colon.

    Large Intestine Histology

    • The mucosa lacks villi but contains goblet cells and deep intestinal glands for secretion and absorption.
    • The muscularis externa features teniae coli, which assist in peristalsis, while other histological features include appendices epiploicae in the serosa.

    Digestion and Absorption

    • Digestion is facilitated primarily by microbiota, producing short-chain fatty acids that nourish enterocytes.
    • Minimal absorption occurs beyond water and minerals, with secretions of mucin aiding lubrication and immune barrier function.

    Motility and Defecation

    • Movement types include segmentation, peristalsis, and mass action contractions to facilitate feces transport.
    • The defecation reflex is triggered by rectal distention, with both involuntary and voluntary mechanisms coordinated for effective bowel evacuation.

    Diseases of the Large Intestine

    • Common pathologies include Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), diverticular disease, and hemorrhoids, each with distinct epidemiological and clinical features.

    Organic Cation Transporter (OCT)

    • Responsible for the uptake of various lipophilic organic cations including acyclovir, lidocaine, epinephrine, norepinephrine, and histamine.

    Biotransformation & Degradation

    Phase I

    • Involves oxidation or reduction reactions mediated by P-450 cytochrome enzymes (CYP450).
    • Key reactions include hydroxylation, dealkylation, and dehalogenation, which insert one atom of oxygen into substrates, increasing polarity.
    • Certain drugs and herbs can influence CYP450 function; for instance, Hypericum perforatum induces many CYP450 enzymes.

    Phase II

    • Focuses on conjugation, where highly hydrophilic compounds are added to substrates, enhancing solubility for excretion.
    • Common conjugates include glucuronate, sulfate, and glutathione.
    • Uridine diphosphate glucuronosyltransferase (UGT) adds glucuronic acid and is located in the smooth endoplasmic reticulum.

    Phase III

    • Conjugated compounds are transported out of hepatocytes into bile or blood.
    • Transport relies on ATP-binding Cassette (ABC) transporters located on both canalicular and sinusoidal membranes.

    Liver Function & Bilirubin Conjugation

    • Senescent erythrocytes are phagocytosed, leading to heme degradation into bilirubin.
    • Unconjugated bilirubin transported to the liver is conjugated by adding glucuronic acid.
    • Bilirubin glucuronide is eventually excreted into bile.

    Cirrhosis: Pathogenesis & Pathophysiology

    • Characterized by activated stellate cells depositing extracellular matrix and loss of sinusoidal endothelial cells.
    • Areas of hepatocyte loss transform into dense fibrous septa, with surviving hepatocytes creating regenerative nodules.

    Cirrhosis: Clinical Features, Progression, & Complications

    • Symptoms are often non-specific and can include anorexia, weight loss, and weakness. Asymptomatic until advanced stages.
    • Potential complications include liver failure, jaundice, encephalopathy, coagulation defects, and increased risk of hepatocellular carcinoma.

    Cholelithiasis (Gallstones)

    • The most common biliary tract disease, affecting 10-20% of adults in high-income regions.
    • Types include cholesterol stones (crystalline cholesterol monohydrate) and pigment stones (bilirubin calcium salts).
    • Major risk factors comprise age, sex (more common in females), obesity, and rapid weight loss.

    Cholelithiasis: Pathogenesis

    • Cholesterol stone formation arises when cholesterol concentrations in bile exceed solubilizing capacity, leading to supersaturation.
    • Factors include bile supersaturation, gallbladder hypomotility, and hypersecretion of mucus leading to aggregation of nucleated crystals.

    Pancreas Anatomy & Histology

    • Comprised of four parts: head, neck, body, and tail.
    • Main pancreatic duct joins the common bile duct at the hepatopancreatic ampulla.
    • The pancreas is a retro-peritoneal structure with a fine capsule dividing it into lobes and lobules.

    Exocrine Pancreas

    • Acini produce digestive enzymes and bicarbonate-rich fluid; contains both acinar and centroacinar cells.
    • Acinar cells secrete inactive zymogens, regulated primarily by CCK, while centroacinar cells secrete bicarbonate in response to secretin.

    Regulation of Pancreatic Secretions

    • Pancreatic secretion is regulated through cephalic (neural), gastric (neural), and intestinal (hormonal) phases.
    • Secretin triggers bicarbonate-rich fluid secretion in response to acidic chyme; CCK stimulates pancreatic enzyme release in response to fats and proteins.

    Pancreatic Secretions

    • Proteolytic enzymes such as trypsin and chymotrypsin are secreted in inactive forms and activated in the duodenum to digest proteins.
    • Insures prevention of pancreatic autodigestion, with trypsin inhibitors serving as protective mechanisms.

    Pancreatic Enzymes

    • Endopeptidases, such as pepsin and trypsin, break peptide bonds within proteins.
    • Exopeptidases, including carboxypeptidase, cleave peptide bonds at the carboxyterminus.

    Trypsin Control Mechanism

    • The trypsin inhibitor prevents premature activation of trypsin within the pancreas to avoid autodigestion.
    • Both genetic defects in trypsin regulation and metabolic imbalances can heighten pancreatitis risk.

    Liver – Anatomy

    • Ligamentum venosum separates the caudate and left lobe; it is a fibrous remnant of the ductus venosus.
    • Gallbladder separates the quadrate and right lobe.
    • The liver is connected to the diaphragm by specific ligaments.

    Liver – Vasculature

    • Blood supply to the liver comes from two sources: hepatic artery (oxygenated blood) and portal vein (deoxygenated, nutrient-rich blood).
    • Both enter the liver through the porta hepatis, which is the entrance for the hepatic artery, portal vein, and common hepatic duct.

    Liver – Histology

    • Main cellular components: hepatocytes, bile canaliculi/cholangiocytes, and hepatic sinusoids.
    • Hepatic stellate cells (Ito cells) and Kupffer cells are also present.

    Hepatocytes

    • Major functional cells of the liver; specialized epithelial cells constitute 80% of liver volume.
    • Arranged into hepatic laminae that are one cell thick, bordered by hepatic sinusoids (vascular spaces).
    • Grooves between cells facilitate the formation of bile canaliculi.

    Liver – Lobular Structure

    • Hepatocytes are organized into lobules surrounding a central vein, cornered by a portal triad.
    • Central vein drains the hepatic sinusoids and leads to the hepatic vein.

    Biotransformation & Degradation

    • Divided into two phases:
      • Phase I: Involves oxidation/reduction reactions (e.g., hydroxylation) typically mediated by CYP450 enzymes, converting substrates into more polar compounds.
      • Phase II: Involves conjugation where a highly hydrophilic compound is added to enhance solubility.
    • Drug interactions can affect CYP450 enzymes, with some compounds increasing enzyme activity.

    Gallbladder Anatomy

    • Pear-shaped organ (approximately 10 cm length, 4 cm cross-section) located on the inferior aspect of the liver; can hold 30-50 mL of bile.
    • Mucosa has numerous folds to enhance the absorptive surface for bile concentration.

    Gallbladder – Histology

    • Mucosa consists of simple columnar epithelium with a lamina propria rich in elastic fibers.
    • Muscularis is thin with fibers oriented in various directions; serosa is simple squamous epithelium.

    Gallbladder Function

    • Stores bile secreted by hepatocytes and concentrates bile by reabsorbing Na, Cl, and water.

    Large Intestine Overview

    • Converts undigested material into feces by water removal and mucus addition; has the largest microbial presence producing Vitamin K and Biotin.
    • Functions include storing and transporting feces with slower motility for absorption.

    Large Intestine Anatomy

    • Begins at ileocecal valve, ends at anus; includes cecum (most prone to perforation), ascending colon, transverse colon, descending colon, and sigmoid colon (narrowest part).
    • Rectum is 12-15 cm long, separated from adjacent structures by Denonvilliers’ fascia.

    Anal Canal

    • Connects the rectum to the anal opening; includes both internal (involuntary) and external (voluntary) anal sphincters.

    Vasculature of the Large Intestine

    • Supplied by branches from the superior mesenteric artery (e.g., ileocolic, right colic, middle colic) and inferior mesenteric artery (e.g., left colic, sigmoid branches, superior rectal artery).
    • Venous supply mirrors arterial supply.

    Innervation of the Large Intestine

    • Sympathetic innervation from T6-T12 and L1-L3; parasympathetic from vagus nerve for the ascending/transverse colon and S2-S4 for descending/sigmoid colon.

    Large Intestine Histology

    • Mucosa lacks folds/villi except in the rectum; primarily consists of simple columnar epithelium with goblet cells and deep crypts filled with lymphoid tissue.
    • Muscularis externa features teniae coli, while serosa contains appendices epiploicae (adipose outpockets).

    Digestion, Absorption, and Secretion

    • Microbiota perform digestion, primarily absorbing water, Na+, and minerals while secreting mucin for lubrication and immune barrier function.

    Motility

    • Includes segmentation, peristalsis, and mass action contractions; conditions like Hirschsprung Disease inhibit normal peristalsis.
    • Gastroileal reflex allows chyme passage from SI to LI; gastrocolic reflex stimulates peristalsis after meals.

    Fluid Homeostasis

    • The large intestine absorbs up to 5 liters of water daily, with Na+ absorption being key to this process, occurring via various mechanisms.

    Defecation

    • Involves rectal distention leading to contractions and communication to the CNS; voluntary control allows the relaxation of internal and external anal sphincters for feces expulsion.
    • Maintenance of fecal continence relies on sphincter tone and puborectalis muscle contraction.

    Diseases of the Large Intestine

    • Common conditions include Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), diverticular disease, and hemorrhoids, each with distinct clinical features and pathogenesis.

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    Explore the vital functions, anatomy, and histology of the liver and gallbladder in this comprehensive quiz. Learn about liver structure, blood supply, and the role of Kupffer cells in metabolism and immunology. Test your knowledge on the key features and functions of this essential organ.

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