{
  "week": 8,
  "title": "Week 8: Body's Defences 2 - GIT Test",
  "questions": [
    {
      "question": "Which list correctly gives the six basic GI processes?",
      "options": [
        "Ingestion, secretion, mixing and propulsion, digestion, absorption, defecation",
        "Ingestion, filtration, mixing, digestion, circulation, urination",
        "Chewing, swallowing, acid production, absorption, respiration, defecation",
        "Ingestion, secretion, immunity, diffusion, absorption, elimination"
      ],
      "correct": 0,
      "explanation": "The six basic GI processes are ingestion, secretion, mixing and propulsion, digestion, absorption, and defecation."
    },
    {
      "question": "Which structures increase the surface area of the small intestine for absorption?",
      "options": [
        "Rugae",
        "Villi and microvilli",
        "Peyer's patches",
        "Tight junctions"
      ],
      "correct": 1,
      "explanation": "Villi are finger-like projections of the mucosa, and microvilli are tiny projections on enterocytes. Together they greatly increase absorptive surface area."
    },
    {
      "question": "What is the primary function of gastric acid in the stomach?",
      "options": [
        "Stimulate appetite",
        "Denature proteins and kill microorganisms",
        "Absorb nutrients",
        "Produce enzymes"
      ],
      "correct": 1,
      "explanation": "Gastric acid creates a very low pH that denatures proteins, activates pepsin, and kills many ingested microorganisms."
    },
    {
      "question": "Which statement best distinguishes segmentation from peristalsis?",
      "options": [
        "Segmentation propels strongly; peristalsis mainly stores food",
        "Segmentation mixes chyme; peristalsis propels contents forward",
        "Segmentation occurs only in the stomach; peristalsis occurs only in the colon",
        "Segmentation is voluntary; peristalsis is voluntary"
      ],
      "correct": 1,
      "explanation": "Segmentation mainly mixes chyme and increases contact with the absorptive surface, whereas peristalsis is mainly a propulsive wave."
    },
    {
      "question": "What is the role of Peyer's patches in the intestine?",
      "options": [
        "Produce digestive enzymes",
        "Sample antigens and initiate immune responses",
        "Absorb water",
        "Secrete mucus"
      ],
      "correct": 1,
      "explanation": "Peyer's patches are lymphoid follicles that help sample intestinal antigens and initiate mucosal immune responses."
    },
    {
      "question": "Which cells secrete antimicrobial peptides in the intestinal crypts?",
      "options": [
        "Goblet cells",
        "Paneth cells",
        "Enterocytes",
        "M cells"
      ],
      "correct": 1,
      "explanation": "Paneth cells at the base of intestinal crypts secrete antimicrobial peptides such as defensins."
    },
    {
      "question": "Which option is part of the intrinsic GI barrier?",
      "options": [
        "Mucus and tight junctions",
        "Only circulating antibodies",
        "Only bone marrow",
        "Only the skin"
      ],
      "correct": 0,
      "explanation": "Intrinsic barriers are built into the gut wall itself and include epithelial cells, tight junctions, mucus, antimicrobial secretions, and rapid renewal."
    },
    {
      "question": "What is colonization resistance provided by the gut microbiome?",
      "options": [
        "Resistance to antibiotics",
        "Prevention of pathogen colonization",
        "Immunity to all diseases",
        "Protection only against viruses"
      ],
      "correct": 1,
      "explanation": "Colonization resistance is the ability of commensal microbes to limit pathogen growth by competing for nutrients and space and supporting barrier function."
    },
    {
      "question": "Which antibody is predominant in mucosal secretions?",
      "options": [
        "IgG",
        "IgA",
        "IgM",
        "IgE"
      ],
      "correct": 1,
      "explanation": "Secretory IgA is the predominant antibody in mucosal secretions and helps block pathogen attachment."
    },
    {
      "question": "What do M cells do in the gut?",
      "options": [
        "Secrete stomach acid",
        "Sample luminal antigens for underlying immune cells",
        "Absorb water in the colon",
        "Produce bile pigments"
      ],
      "correct": 1,
      "explanation": "M cells over Peyer's patches sample luminal material and deliver antigens to underlying immune cells."
    },
    {
      "question": "What are lacteals?",
      "options": [
        "Milk-producing glands",
        "Lymphatic capillaries in villi that absorb fats",
        "Enzymes for digestion",
        "Nerve cells"
      ],
      "correct": 1,
      "explanation": "Lacteals are lymphatic capillaries within intestinal villi that absorb dietary fats and fat-soluble vitamins."
    },
    {
      "question": "What is chyme?",
      "options": [
        "A digestive enzyme",
        "Semi-fluid mass of partially digested food",
        "A type of bacteria",
        "Hormone produced by stomach"
      ],
      "correct": 1,
      "explanation": "Chyme is the semi-fluid mass of partially digested food mixed with gastric secretions and enzymes."
    },
    {
      "question": "What is the difference between parietal and visceral peritoneum?",
      "options": [
        "There is no difference",
        "Parietal lines the abdominal wall; visceral covers the organs",
        "Visceral lines the abdominal wall; parietal covers the organs",
        "Both cover the same structures"
      ],
      "correct": 1,
      "explanation": "The parietal peritoneum lines the abdominal wall, while the visceral peritoneum covers the abdominal organs."
    },
    {
      "question": "What is receptive relaxation?",
      "options": [
        "The reflex relaxation of the stomach as food enters",
        "The forceful contraction that causes vomiting",
        "The tightening of the pyloric sphincter",
        "The closure of tight junctions after a meal"
      ],
      "correct": 0,
      "explanation": "Receptive relaxation is a reflex-mediated relaxation of the proximal stomach that allows it to receive an incoming meal."
    },
    {
      "question": "What is gastric accommodation?",
      "options": [
        "The secretion of hydrochloric acid",
        "The ability of the stomach to stretch and store a meal",
        "The movement of bile into the duodenum",
        "The absorption of vitamin B12"
      ],
      "correct": 1,
      "explanation": "Gastric accommodation is the ability of the stomach to expand and store a meal without a large rise in intragastric pressure."
    },
    {
      "question": "What is the function of the migrating motor complex?",
      "options": [
        "Digest fats",
        "Sweep bacteria and debris during fasting",
        "Produce hormones",
        "Absorb nutrients"
      ],
      "correct": 1,
      "explanation": "The migrating motor complex is a fasting-phase housekeeping pattern that sweeps residual contents and bacteria through the stomach and small intestine."
    },
    {
      "question": "Which cells act as pacemaker cells in the GI tract?",
      "options": [
        "Goblet cells",
        "Interstitial cells of Cajal",
        "Parietal cells",
        "Chief cells"
      ],
      "correct": 1,
      "explanation": "Interstitial cells of Cajal generate slow-wave electrical rhythms that help coordinate GI motility."
    },
    {
      "question": "What is the enteric nervous system sometimes called?",
      "options": [
        "The third brain",
        "The second brain",
        "The digestive brain",
        "The gut processor"
      ],
      "correct": 1,
      "explanation": "The enteric nervous system is often called the second brain because it can coordinate many GI functions independently."
    },
    {
      "question": "Which process is the final elimination step for indigestible GI contents?",
      "options": [
        "Segmentation",
        "Absorption",
        "Defecation",
        "Accommodation"
      ],
      "correct": 2,
      "explanation": "Defecation is the final GI process in which material that cannot be digested or absorbed is eliminated."
    },
    {
      "question": "Which metabolic complication results from loss of hydrogen ions during vomiting?",
      "options": [
        "Metabolic acidosis",
        "Metabolic alkalosis",
        "Respiratory acidosis",
        "Respiratory alkalosis"
      ],
      "correct": 1,
      "explanation": "Vomiting causes loss of gastric acid, which commonly leads to metabolic alkalosis."
    },
    {
      "question": "What electrolyte abnormality commonly occurs with chronic vomiting?",
      "options": [
        "Hyperkalaemia",
        "Hypokalaemia",
        "Hypernatraemia",
        "Hypercalcaemia"
      ],
      "correct": 1,
      "explanation": "Hypokalaemia commonly develops with prolonged vomiting because of potassium loss and renal compensation."
    },
    {
      "question": "What is hypochloraemia?",
      "options": [
        "High chloride levels",
        "Low chloride levels",
        "Normal chloride levels",
        "Absent chloride"
      ],
      "correct": 1,
      "explanation": "Hypochloraemia means abnormally low blood chloride, commonly due to loss of gastric hydrochloric acid during vomiting."
    },
    {
      "question": "What is the oral microbiome?",
      "options": [
        "A single bacterial species",
        "Over 700 bacterial species colonizing the oral cavity",
        "Fungal infections only",
        "Viral particles in saliva"
      ],
      "correct": 1,
      "explanation": "The oral microbiome is a diverse microbial community that colonizes teeth, saliva, and oral mucosal surfaces."
    },
    {
      "question": "What is the function of goblet cells in the GI tract?",
      "options": [
        "Absorb nutrients",
        "Secrete mucus",
        "Produce acid",
        "Generate enzymes"
      ],
      "correct": 1,
      "explanation": "Goblet cells secrete mucus that helps protect the epithelial surface from mechanical, chemical, and microbial injury."
    },
    {
      "question": "What structure allows the stomach to expand significantly when filled?",
      "options": [
        "Tight junctions",
        "Rugae",
        "Microvilli",
        "Peyer's patches"
      ],
      "correct": 1,
      "explanation": "Rugae are folds in the gastric mucosa that help the stomach expand as it fills."
    },
    {
      "question": "Which term best matches the following definition: \"Pacemaker cells of the GI tract that generate slow-wave electrical rhythms helping coordinate peristalsis and segmentation.\"?",
      "options": [
        "Gastric Acid",
        "Tight Junctions",
        "Interstitial Cells of Cajal",
        "Secretory IgA"
      ],
      "correct": 2,
      "explanation": "Interstitial Cells of Cajal is defined as Pacemaker cells of the GI tract that generate slow-wave electrical rhythms helping coordinate peristalsis and segmentation.",
      "difficulty": "easy",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"The potential self-destruction of GI tissues by the body's own digestive enzymes and acids, prevented by mucus barriers and tight junctions.\"?",
      "options": [
        "Gastric Accommodation",
        "Segmentation",
        "Interstitial Cells of Cajal",
        "Auto-digestion"
      ],
      "correct": 3,
      "explanation": "Auto-digestion is defined as The potential self-destruction of GI tissues by the body's own digestive enzymes and acids, prevented by mucus barriers and tight junctions.",
      "difficulty": "medium",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"Mucus-secreting cells interspersed throughout the intestinal epithelium that produce mucin to form a protective mucus layer.\"?",
      "options": [
        "Goblet Cells",
        "Enteric Nervous System",
        "Gut Microbiome",
        "Interstitial Cells of Cajal"
      ],
      "correct": 0,
      "explanation": "Goblet Cells is defined as Mucus-secreting cells interspersed throughout the intestinal epithelium that produce mucin to form a protective mucus layer.",
      "difficulty": "easy",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"Protein complexes connecting epithelial cells that regulate paracellular transport and maintain the barrier between intestinal lumen and tissues.\"?",
      "options": [
        "Segmentation",
        "Tight Junctions",
        "Villi",
        "Peristalsis"
      ],
      "correct": 1,
      "explanation": "Tight Junctions is defined as Protein complexes connecting epithelial cells that regulate paracellular transport and maintain the barrier between intestinal lumen and tissues.",
      "difficulty": "medium",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"Protective mechanisms supporting GI defence beyond the epithelial lining, including immune responses and neural control of motility.\"?",
      "options": [
        "Secretory IgA",
        "Extrinsic Barrier",
        "Gastric Accommodation",
        "Auto-digestion"
      ],
      "correct": 1,
      "explanation": "Extrinsic Barrier is defined as Protective mechanisms supporting GI defence beyond the epithelial lining, including immune responses and neural control of motility.",
      "difficulty": "easy",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"Hydrochloric acid secreted by parietal cells in the stomach, creating a pH of 1.5-3.5 that denatures proteins, activates pepsin, and kills microorganisms.\"?",
      "options": [
        "Intrinsic Barrier",
        "Alimentary Canal",
        "Gastric Acid",
        "Peristalsis"
      ],
      "correct": 2,
      "explanation": "Gastric Acid is defined as Hydrochloric acid secreted by parietal cells in the stomach, creating a pH of 1.5-3.5 that denatures proteins, activates pepsin, and kills microorganisms.",
      "difficulty": "medium",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"Abnormally low potassium levels in blood, a complication of vomiting due to loss in vomitus and renal compensation for metabolic alkalosis.\"?",
      "options": [
        "Paneth Cells",
        "Secretory IgA",
        "Hypokalaemia",
        "Defecation"
      ],
      "correct": 2,
      "explanation": "Hypokalaemia is defined as Abnormally low potassium levels in blood, a complication of vomiting due to loss in vomitus and renal compensation for metabolic alkalosis.",
      "difficulty": "easy",
      "learning_objective": "expanded_bio_terminology"
    },
    {
      "question": "Which term best matches the following definition: \"The digestive tube including mouth, pharynx, esophagus, stomach, small intestine, and large intestine through which food passes.\"?",
      "options": [
        "Hypokalaemia",
        "Extrinsic Barrier",
        "Alimentary Canal",
        "Gastric Accommodation"
      ],
      "correct": 2,
      "explanation": "Alimentary Canal is defined as The digestive tube including mouth, pharynx, esophagus, stomach, small intestine, and large intestine through which food passes.",
      "difficulty": "easy",
      "learning_objective": "expanded_bio_terminology"
    }
  ]
}