Podcast
Questions and Answers
Which of the following physiological responses would most likely occur if somatostatin secretion were completely inhibited?
Which of the following physiological responses would most likely occur if somatostatin secretion were completely inhibited?
A patient presents with a condition causing excessive gastrin secretion. Which of the following symptoms would be the most likely consequence?
A patient presents with a condition causing excessive gastrin secretion. Which of the following symptoms would be the most likely consequence?
If the vagus nerve (a major component of the parasympathetic nervous system) is severed, what effect would this have on GI function during digestion?
If the vagus nerve (a major component of the parasympathetic nervous system) is severed, what effect would this have on GI function during digestion?
A researcher is investigating the effects of a novel drug on digestive processes. The drug selectively inhibits the submucosal (Meissner’s) plexus. Which of the following would be the expected outcome?
A researcher is investigating the effects of a novel drug on digestive processes. The drug selectively inhibits the submucosal (Meissner’s) plexus. Which of the following would be the expected outcome?
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What is the most likely effect of increased sympathetic nervous system activity on gastrointestinal function?
What is the most likely effect of increased sympathetic nervous system activity on gastrointestinal function?
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A patient with a history of gallstones experiences severe abdominal pain after consuming a high-fat meal. Which of the following hormones is most likely involved in this patient's discomfort?
A patient with a history of gallstones experiences severe abdominal pain after consuming a high-fat meal. Which of the following hormones is most likely involved in this patient's discomfort?
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Following gastric bypass surgery, patients often experience a rapid emptying of gastric contents into the small intestine. Which hormone's function is most directly compromised by this surgical alteration?
Following gastric bypass surgery, patients often experience a rapid emptying of gastric contents into the small intestine. Which hormone's function is most directly compromised by this surgical alteration?
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A pharmaceutical company is developing a drug that mimics the action of secretin. What potential therapeutic effects could be expected from this medication?
A pharmaceutical company is developing a drug that mimics the action of secretin. What potential therapeutic effects could be expected from this medication?
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Which of the following stimuli primarily activates sensory receptors along afferent fibers of the vagus nerve, influencing digestive processes?
Which of the following stimuli primarily activates sensory receptors along afferent fibers of the vagus nerve, influencing digestive processes?
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Damage to the superior cervical ganglion would most likely disrupt which digestive function?
Damage to the superior cervical ganglion would most likely disrupt which digestive function?
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Which scenario is the BEST example of a gastrocolic reflex?
Which scenario is the BEST example of a gastrocolic reflex?
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A patient with xerostomia (dry mouth) is MOST likely to experience difficulty with which of the following digestive processes?
A patient with xerostomia (dry mouth) is MOST likely to experience difficulty with which of the following digestive processes?
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If the lower esophageal sphincter malfunctions, allowing stomach acid to reflux into the esophagus, which secretion is MOST critical for protecting the esophageal lining?
If the lower esophageal sphincter malfunctions, allowing stomach acid to reflux into the esophagus, which secretion is MOST critical for protecting the esophageal lining?
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Following a partial gastrectomy (removal of part of the stomach), a patient might develop pernicious anemia due to the reduced secretion of which substance?
Following a partial gastrectomy (removal of part of the stomach), a patient might develop pernicious anemia due to the reduced secretion of which substance?
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Which of the following exemplifies the exocrine function of the pancreas during digestion?
Which of the following exemplifies the exocrine function of the pancreas during digestion?
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A patient with liver cirrhosis experiences impaired synthesis of bile. This would MOST directly affect the digestion and absorption of which nutrient?
A patient with liver cirrhosis experiences impaired synthesis of bile. This would MOST directly affect the digestion and absorption of which nutrient?
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Flashcards
Gastrin
Gastrin
A hormone secreted by G cells that stimulates gastric acid secretion.
CCK
CCK
Cholecystokinin, a hormone that triggers gallbladder contraction and stimulates the pancreas.
Secretin
Secretin
A hormone released from the duodenum in response to low pH that stimulates bicarbonate release.
Somatostatin
Somatostatin
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Enteric Nervous System
Enteric Nervous System
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Myenteric Plexus
Myenteric Plexus
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Submucosal Plexus
Submucosal Plexus
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Chyme
Chyme
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Sensory information transmission
Sensory information transmission
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Parasympathetic nerves to the gut
Parasympathetic nerves to the gut
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Sympathetic innervation to salivary glands
Sympathetic innervation to salivary glands
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Digestive reflexes
Digestive reflexes
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Main secretion of the mouth
Main secretion of the mouth
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Function of mucus in the esophagus
Function of mucus in the esophagus
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Liver secretion into the lumen
Liver secretion into the lumen
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Pancreatic secretions into the lumen
Pancreatic secretions into the lumen
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Study Notes
Digestive Hormones and Regulation
- Types of Digestive Hormones: Polypeptides are the most likely type.
Major Digestive Hormones
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Gastrin: Released by G cells in the stomach and duodenum, stimulated by food in the stomach or duodenum. Stimulates gastric release of hydrochloric acid and pepsinogen.
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Secretin: Secreted by the duodenum. Released in response to low pH (chyme entering the duodenum). Affects the pancreas (bicarbonate release, acid inhibition), and slows peristalsis.
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CCK: Secreted by cells in the duodenum and jejunum in response to lipids and their catabolites. Stimulates gallbladder contraction, pancreas, slowing gastric emptying, and the satiety center.
Other Digestive Hormones
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Somatostatin: Released by cells in gastric glands and the pancreas (and some hypothalamic cells). Functions to inhibit secretions of the stomach, duodenum, and pancreas, reducing nutrient absorption.
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VIP: Produces vasodilation in GI tract blood vessels during digestion in response to parasympathetic input.
Nutrient Absorption and Blood Flow
- Increased blood flow to the GI tract: Ensures adequate oxygen to working cells and nutrient absorption, facilitating plasma precursor for mucus secretions.
Regulation by Nervous Systems
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CNS and Autonomic Outflow: GI secretions are regulated via the CNS (autonomic outflow). Parasympathetic activity is generally more prominent than sympathetic during digestion.
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Enteric Nervous System (ENS): Moderates GI secretions and directly influences GI cells, extending along the length of the digestive tract composed of the Myenteric and Submucosal plexuses.
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Myenteric Plexus: Regulates smooth muscle contraction, causing peristalsis and sphincter control.
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Submucosal Plexus: Regulates secretions and blood flow throughout the digestive tract.
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Sensory Inputs: The plexuses detect mechanical (stretch, tension), thermal, osmotic, and chemical stimuli, transmitted to the CNS along afferent vagal fibers.
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Parasympathetic Nerves: The vagus nerve (and IX, VII) innervate most of the digestive tract. IX and VII innervate salivary glands, with sacral nerves innervating the colon.
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Sympathetic Innervation: Splanchnic nerves conduct sympathetic innervation to most of the GI tract, while superior cervical ganglion nerves innervate salivary glands.
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Digestive Reflexes: Digestive reflexes involve sensory input relayed to the CNS, which triggers motor responses.
Secretion from Various Digestive Organs
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Mouth: Saliva is the major secretion.
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Esophagus: Mucous (bicarbonate rich) lubricates and protects against acid erosion.
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Stomach: Secretes gastrin into the blood; hydrochloric acid, pepsinogen, mucous, gastroferrin, and intrinsic factor into the digestive tract.
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Small Intestine: Secretes secretin and CCK into the blood; mucous, lysozyme, defensins into the lumen.
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Colon: Secretes mucous rich in mucin.
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Pancreas: Secretes insulin, glucagon, somatostatin into the blood, pancreatic enzymes (lipase, amylase, ribonucleases) and inactive enzymes (trypsinogen, chymotrypsinogen, procarboxypeptidases A & B, pro-elastase) into the lumen, and bicarbonate-rich fluid (up to 2 liters/day).
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Liver: Synthesizes plasma proteins, VLDLs, and HDLs, releasing them into the blood, and secretes bile into the lumen. Bile contains bile salts/acids for lipid emulsification, and bilirubin from heme breakdown.
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Description
Explore the key digestive hormones including Gastrin, Secretin, CCK, Somatostatin, and VIP. This quiz covers their functions, secretion sites, and physiological roles in digestion. Test your knowledge and understanding of how these hormones influence digestive processes.
