GI Intro To GI Histology MCQ Quiz

The small intestine is the most important part of the gastrointestinal system for digestion and absorption. It is responsible for the majority of nutrient absorption, including fats. In this case, the patient's symptoms of recurrent fatty diarrhea and malabsorption suggest a problem with fat digestion and absorption, which is most likely occurring in the small intestine.

The chronic burning sensation in the patient's chest, worsened by lying down at night after a meal and relieved by over-the-counter antacids, suggests gastroesophageal reflux disease (GERD). The lower esophageal sphincter (LES) is responsible for preventing the backflow of stomach acid into the esophagus. Dysfunction of the LES can lead to the symptoms described by the patient, making it the most likely gastrointestinal structure causing the pain.

The probable diagnosis for the given scenario is acute appendicitis. The patient's symptoms, such as pain starting in the central abdomen and localizing to the lower right abdomen, along with nausea, vomiting, and increased temperature, are characteristic of appendicitis. Appendicitis refers to the inflammation of the appendix, a small pouch-like organ located in the lower right abdomen. It is a medical emergency that requires immediate surgical intervention to remove the inflamed appendix and prevent complications such as rupture and infection.

Rugae is not a characteristic feature of the small intestine. Rugae are folds or ridges that are typically found in the stomach, not in the small intestine. The small intestine is lined with plicae circulars, which are circular folds that increase the surface area for absorption. It also has microvilli, which are tiny projections on the surface of the intestinal cells that further increase the surface area for absorption. Villi are finger-like projections on the surface of the small intestine that also increase the surface area for absorption. Peyer's patches are lymphoid tissue found in the small intestine that play a role in the immune system.

Parietal cells possess receptors for gastrin. Gastrin is a hormone that is released by the stomach and plays a role in stimulating the secretion of gastric acid. Parietal cells are responsible for producing and secreting gastric acid, and they have specific receptors that bind to gastrin. This binding of gastrin to the receptors on parietal cells triggers the release of gastric acid, which is important for the digestion of food in the stomach.

Fatty acids in the duodenum are the primary signal for the release of CCK from intestinal cells into the blood. When fatty acids are present in the duodenum, they stimulate the release of CCK, which then acts on the smooth muscle of the stomach to inhibit gastric motility and promote relaxation. This helps to slow down the movement of food through the digestive system, allowing for proper digestion and absorption of nutrients.

The migrating motor complex is a pattern of smooth muscle contraction that occurs in the stomach and small intestines during a period of fasting. It is characterized by a series of contractions that sweep through the digestive tract, clearing out any remaining food particles and preventing bacterial overgrowth. This pattern of contraction helps to maintain the health and function of the digestive system during periods of fasting.

The hormone secretin is responsible for regulating the pH of pancreatic ductular secretion and the volume of pancreatic secretion. Therefore, if the mouse lacks secretin, it is expected that the pH of pancreatic ductular secretion and the volume of pancreatic secretion would be increased. However, the absence of secretin would not directly affect the pH of duodenal contents or gallbladder contractibility. Additionally, secretin plays a role in protecting the duodenum from erosions and ulcerations. Therefore, without secretin, the mutant mouse would have an increased susceptibility to duodenal erosions and ulcerations.

G cells are enteroendocrine cells (EECs) and they produce gastrin.

As the rate of secretion increases in both the salivary glands and pancreas, bicarbonate ions are found to increase the most. Bicarbonate ions are important in maintaining the pH balance in the body. They help neutralize the acidic environment in the digestive system, especially in the stomach. Increased secretion of bicarbonate ions in the salivary glands and pancreas aids in the digestion process by providing an alkaline environment for enzymes to function optimally.

As saliva passes through the striated duct, the change that occurs is active absorption of Na+. This means that sodium ions are being actively transported out of the duct and into the surrounding tissue. This process helps to regulate the concentration of sodium in the saliva and maintain the overall balance of ions in the body.

In a normal individual, the bolus of dilute acid in the distal esophagus will be cleared predominantly by secondary peristalsis. Secondary peristalsis is a reflexive contraction of the esophageal muscles that occurs in response to the presence of a bolus or food residue in the esophagus. It helps to propel the bolus further down the esophagus and into the stomach. Primary peristalsis, which is the initial wave of muscular contractions that begins in the upper esophagus, may also contribute to the clearance of the bolus, but secondary peristalsis is the predominant mechanism.

Chief cells are located primarily in the neck region of the gastric glands and they are responsible for producing pepsinogen, which is the inactive form of pepsin. Pepsinogen is then converted into pepsin by the acidic environment in the stomach. Pepsin is an enzyme that plays a key role in the digestion of proteins. Therefore, the statement "Chief cells produce pepsin" is correct.

Centroacinar cells cannot be found in the submandibular gland. These cells are located in the pancreas and are responsible for producing digestive enzymes. The submandibular gland, on the other hand, contains mucous acini, serous acini, intercalated ducts, and striated ducts.

APUD cells, also known as enterochromaffin-like cells, are found in the gastric glands of the fundus/body region of the stomach. These cells produce and release histamine, which plays a role in regulating gastric acid secretion. This statement accurately describes the histological structures in the fundus/body region of the stomach.

The correct answer is inhibitory neurons from the myenteric plexus. These neurons mediate the response of the smooth muscle in the stomach to accommodate the meal by inhibiting its contraction. This allows the stomach to expand and accommodate the food that is being swallowed.

Based on the information given, scintigraphy is a test that tracks the transit of a swallowed tracer through the gut. The question asks how long it would take for the tracer to appear in the colon for a volunteer with normal gastrointestinal function. The correct answer is 7 - 10 hours, indicating that it takes approximately this amount of time for the tracer to reach the colon.

Histamine has the greatest impact on acid secretion by the parietal cells of the gastric mucosa. Histamine acts as a potent stimulant for acid secretion and binds to H2 receptors on the parietal cells, triggering the production and release of gastric acid. Acetylcholine and gastrin also play a role in stimulating acid secretion, but histamine has a stronger effect. Somatostatin, on the other hand, inhibits acid secretion and acts as a negative regulator.