MBBS Year 1 Gastrointestinal Lectures
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Questions and Answers

What is the primary function of retropulsion in the stomach?

  • To mix food with gastric acid and pepsin
  • To absorb nutrients into the bloodstream
  • To break down solid particles into smaller pieces (correct)
  • To propel food into the duodenum

    • During which phase of gastric acid secretion is the majority of acid produced?

  • Cephalic phase
  • Gastric phase (correct)
  • Basal phase
  • Intestinal phase

    • What is the primary function of HCO3- in gastric mucus?

  • To inhibit the secretion of gastric acid
  • To stimulate the secretion of gastric acid
  • To neutralize H+ ions (correct)
  • To digest proteins

    • What is the term for the process by which food is propelled back into the stomach for further breakdown?

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

    What is the pH of the stomach contents during the fasting state?

    <p>pH 1-2</p> Signup and view all the answers

    What is the primary function of the mucus layer in the stomach?

    <p>To protect the stomach lining from acid and enzymes</p> Signup and view all the answers

    What is the term for the complex of tubulovesicles and intracellular canaliculi in the parietal cell?

    <p>Tubulovesicle complex</p> Signup and view all the answers

    What is the primary function of blood flow in the stomach?

    <p>To supply nutrients for HCl secretion and buffering via HCO3-</p> Signup and view all the answers

    Which of the following salivary secretions plays a crucial role in breaking down complex carbohydrates?

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

    What is the primary function of the gastric mucosal barrier?

    <p>To protect the stomach lining from acid damage</p> Signup and view all the answers

    Which of the following phases of acid secretion is stimulated by the sight and smell of food?

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

    What is the primary function of pancreatic juice?

    <p>To facilitate the digestion of proteins</p> Signup and view all the answers

    Which of the following hormones is released in response to the presence of acid in the duodenum?

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

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

    <p>To produce pancreatic enzymes</p> Signup and view all the answers

    Which of the following is NOT a function of saliva?

    <p>Regulating the release of gastric hormones</p> Signup and view all the answers

    What is the primary function of the gastric mucosal barrier?

    <p>To protect the stomach epithelium from acid secretion</p> Signup and view all the answers

    Which of the following textbooks is NOT a recommended resource for MBBS Year 1 Gastrointestinal Lectures?

    <p>Guyton and Hall Textbook of Medical Physiology</p> Signup and view all the answers

    What is the role of intrinsic factor in the stomach?

    <p>It aids in the absorption of vitamin B12</p> Signup and view all the answers

    What is the primary stimulant of HCl secretion by parietal cells?

    <p>All of the above</p> Signup and view all the answers

    What is the structure of the glandular stomach epithelium?

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

    What is the function of surface mucous cells in the stomach?

    <p>To produce a thin film of mucous</p> Signup and view all the answers

    What is the result of the structural changes in parietal cells during HCl secretion?

    <p>A marked increase in the tubulovesicular system</p> Signup and view all the answers

    What is the primary component of gastric juice?

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

    What is the location of the absorption of vitamin B12?

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

    What is the primary function of the CCK2 receptor in the ECL cell?

    <p>Stimulating the release of histamine</p> Signup and view all the answers

    Which of the following neurotransmitters is involved in the physiological stimulation of gastric acid secretion?

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

    What is the role of the ECL cell in the regulation of gastric acid secretion?

    <p>To produce and release histamine</p> Signup and view all the answers

    Which receptor is localized on the parietal cell and involved in the regulation of gastric acid secretion?

    <p>H2</p> Signup and view all the answers

    What is the primary source of gastrin in the gastric mucosa?

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

    What is the effect of histamine on parietal cells?

    <p>Stimulating the release of HCl</p> Signup and view all the answers

    What is the mechanism by which omeprazole inhibits gastric HCl secretion?

    <p>By forming a disulphide link with H+,K+-ATPase and blocking the enzyme irreversibly</p> Signup and view all the answers

    What is the primary function of pancreatic juice?

    <p>To neutralize duodenal content and facilitate enzyme activity</p> Signup and view all the answers

    What is the primary function of the intestinal phase of acid secretion?

    <p>To regulate the release of intestinal hormones that target acid-secreting cells</p> Signup and view all the answers

    What is the composition of pancreatic juice?

    <p>Rich in HCO3- and enzymes</p> Signup and view all the answers

    What is the primary function of lipase in pancreatic juice?

    <p>To hydrolyze neutral fat into glycerol and fatty acids</p> Signup and view all the answers

    What is the rate of protein synthesis in the pancreas?

    <p>Highest rate of protein synthesis of any secretory tissue</p> Signup and view all the answers

    What is the primary function of cholecystokinin?

    <p>To stimulate the release of pancreatic juice rich in enzymes</p> Signup and view all the answers

    What is the primary function of trypsinogen in pancreatic juice?

    <p>To break down proteins into peptides</p> Signup and view all the answers

    Study Notes

    MBBS Year 1 Gastrointestinal Lectures

    • Lectures cover the overview of the digestive system, digestion and absorption of nutrients, salivary, gastric, and pancreatic secretions, bile and biliary system, and motility of the gut.

    Salivary Secretions

    • Salivary glands produce saliva, which has several functions:
      • Lubricates food for easy swallowing
      • Aids in chewing and digestion
      • Helps in oral cavity cleanliness
      • Has antibacterial properties
    • Salivary secretion is controlled by the nervous system and hormones.
    • Factors influencing salivary secretion include:
      • Parasympathetic stimulation
      • Sympathetic stimulation
      • Hormonal stimulation
      • Reflex stimulation

    Gastric Acid Secretion

    • Gastric acid secretion is divided into basal (fasting) and stimulated (post-prandial) phases.
    • The three phases of gastric acid secretion are:
      • Cephalic phase: triggered by the sight, smell, and taste of food
      • Gastric phase: stimulated by the presence of food in the stomach
      • Intestinal phase: influenced by the presence of food in the small intestine
    • Mucus and bicarbonate secretion create a gastric mucosal barrier, protecting the stomach from acid and enzymes.
    • The stomach epithelium undergoes structural changes during HCl secretion, forming a markedly increased tubulovesicular system for proton secretion.

    Gastric Mucosal Defense

    • The gastric mucosal barrier consists of:
      • Mucus layer
      • HCO3- secretion
      • Tight junctions
    • This barrier protects the stomach from acid and enzymes, maintaining a neutral pH.

    Pancreatic Secretion

    • Pancreatic juice has a physiological function of:
      • Neutralizing duodenal content
      • Aiding in protein digestion
    • Factors causing release of secretin and cholecystokinin include:
      • Presence of acid in the duodenum
      • Presence of fats in the small intestine
    • These intestinal hormones modify the composition of pancreatic juice, increasing HCO3- secretion and enzyme production.

    Pancreatic Juice Composition

    • Pancreatic juice is composed of:
      • Aqueous component rich in HCO3
      • Enzyme component
      • Proteolytic enzymes (trypsinogen, chymotrypsinogen, procarboxypolypeptidase, ribonuclease, deoxyribonuclease)
      • Amylase (breaks down starch and glycogen)
      • Lipase (hydrolyzes neutral fat into glycerol and fatty acids)

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    Description

    A comprehensive review of the digestive system, covering digestion, absorption, and physiology. Topics include salivary, gastric, and pancreatic secretions, bile and biliary system, and motility of the gut.

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