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Questions and Answers
Which component is NOT secreted by the stomach?
Which component is NOT secreted by the stomach?
What is the primary role of pepsin in the stomach?
What is the primary role of pepsin in the stomach?
What is the function of the gastric mucosal folds?
What is the function of the gastric mucosal folds?
What substance helps kill bacteria in the stomach?
What substance helps kill bacteria in the stomach?
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What is the nature of the chyme moved from the stomach to the duodenum?
What is the nature of the chyme moved from the stomach to the duodenum?
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What is the primary site of carbohydrate digestion in the stomach?
What is the primary site of carbohydrate digestion in the stomach?
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Which of the following statements about pepsin is true?
Which of the following statements about pepsin is true?
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Which substances are known to be absorbed in the stomach?
Which substances are known to be absorbed in the stomach?
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What effect does acidity have on salivary amylase in the stomach?
What effect does acidity have on salivary amylase in the stomach?
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Which of the following describes the mechanism of gastric secretion control?
Which of the following describes the mechanism of gastric secretion control?
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Which component of gastric gland secretion is responsible for protein digestion?
Which component of gastric gland secretion is responsible for protein digestion?
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What is the main function of hydrochloric acid in the stomach?
What is the main function of hydrochloric acid in the stomach?
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Which cells are responsible for secreting intrinsic factor?
Which cells are responsible for secreting intrinsic factor?
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What role does somatostatin play in gastric secretion?
What role does somatostatin play in gastric secretion?
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Which of the following is a product of surface mucous cells in the gastric gland?
Which of the following is a product of surface mucous cells in the gastric gland?
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Which of the following substances regulates gastric secretion but is not secreted by gastric gland cells?
Which of the following substances regulates gastric secretion but is not secreted by gastric gland cells?
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What is the primary function of mucus and bicarbonate in gastric secretion?
What is the primary function of mucus and bicarbonate in gastric secretion?
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Which cells in the gastric gland contribute to the regulation of gastric secretion via the hormone histamine?
Which cells in the gastric gland contribute to the regulation of gastric secretion via the hormone histamine?
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What triggers the cephalic phase of gastric secretion?
What triggers the cephalic phase of gastric secretion?
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Which phase of gastric secretion is primarily initiated by food entering the stomach?
Which phase of gastric secretion is primarily initiated by food entering the stomach?
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What effect does the intestinal phase have on gastric secretion?
What effect does the intestinal phase have on gastric secretion?
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Which of the following is NOT a factor in the gastric phase of secretion?
Which of the following is NOT a factor in the gastric phase of secretion?
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What role does gastrin play in gastric secretion?
What role does gastrin play in gastric secretion?
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What is the primary control mechanism for the intestinal phase?
What is the primary control mechanism for the intestinal phase?
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During which phase does the thought of food primarily increase gastric secretion?
During which phase does the thought of food primarily increase gastric secretion?
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Which scenario is least likely to stimulate gastric secretion?
Which scenario is least likely to stimulate gastric secretion?
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What is the primary role of the gastric mucosal barrier?
What is the primary role of the gastric mucosal barrier?
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Which component of the gastric mucosal barrier serves as a chemical barrier against acid?
Which component of the gastric mucosal barrier serves as a chemical barrier against acid?
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How often is the entire stomach lining replaced?
How often is the entire stomach lining replaced?
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Which function is primarily performed in the duodenum and jejunum of the small intestine?
Which function is primarily performed in the duodenum and jejunum of the small intestine?
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What structural feature increases the surface area of the small intestine?
What structural feature increases the surface area of the small intestine?
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Which enzyme is NOT expressed on the membranes of microvilli?
Which enzyme is NOT expressed on the membranes of microvilli?
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What role do prostaglandins play in gastric function?
What role do prostaglandins play in gastric function?
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Which of the following is a primary mechanism for mixing and propelling chyme in the small intestine?
Which of the following is a primary mechanism for mixing and propelling chyme in the small intestine?
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What is the major site of absorption in the small intestine?
What is the major site of absorption in the small intestine?
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Which feature is NOT part of the digestive processes in the small intestine?
Which feature is NOT part of the digestive processes in the small intestine?
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The stomach is a J-shaped, ______-like chamber.
The stomach is a J-shaped, ______-like chamber.
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The main function of the stomach includes storing ingested food and secreting ______.
The main function of the stomach includes storing ingested food and secreting ______.
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One of the functions of the stomach is to mix food with gastric juice and ______ it.
One of the functions of the stomach is to mix food with gastric juice and ______ it.
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The partially digested food that moves from the stomach to the duodenum is called ______.
The partially digested food that moves from the stomach to the duodenum is called ______.
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The stomach kills bacteria through the action of ______.
The stomach kills bacteria through the action of ______.
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Carbohydrate digestion in the stomach is aided by salivary ______.
Carbohydrate digestion in the stomach is aided by salivary ______.
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Pepsin partially digests ______ in the antrum of the stomach.
Pepsin partially digests ______ in the antrum of the stomach.
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Acidity in the stomach leads to partial ______ of salivary amylase.
Acidity in the stomach leads to partial ______ of salivary amylase.
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Only ______ and aspirin are absorbed in the stomach.
Only ______ and aspirin are absorbed in the stomach.
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The control of gastric secretion includes various ______ mechanisms.
The control of gastric secretion includes various ______ mechanisms.
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The ______ phase of gastric secretion is triggered by thoughts, smells, sights, or tastes of food.
The ______ phase of gastric secretion is triggered by thoughts, smells, sights, or tastes of food.
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The presence of food in the stomach triggers the ______ phase of gastric secretion.
The presence of food in the stomach triggers the ______ phase of gastric secretion.
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The ______ phase is initiated by the movement of food from the stomach into the duodenum.
The ______ phase is initiated by the movement of food from the stomach into the duodenum.
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The excitatory phases of gastric secretion include both the ______ and gastric phases.
The excitatory phases of gastric secretion include both the ______ and gastric phases.
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The ______ phase of gastric secretion inhibits further gastric activity.
The ______ phase of gastric secretion inhibits further gastric activity.
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The keys to controlling gastric secretion include the cephalic, gastric, and ______ phases.
The keys to controlling gastric secretion include the cephalic, gastric, and ______ phases.
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The ______ receptor activation in parietal cells is responsible for stimulating the proton pump.
The ______ receptor activation in parietal cells is responsible for stimulating the proton pump.
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Factors from the brain, such as thoughts of food, activate the ______ phase of gastric secretion.
Factors from the brain, such as thoughts of food, activate the ______ phase of gastric secretion.
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The primary component secreted by the parietal cell is ______.
The primary component secreted by the parietal cell is ______.
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The chief cell of the gastric gland secretes ______.
The chief cell of the gastric gland secretes ______.
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Intrinsic factor is important for the absorption of ______.
Intrinsic factor is important for the absorption of ______.
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Surface mucous cells secrete ______ for gastroprotection.
Surface mucous cells secrete ______ for gastroprotection.
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The regulation of gastric secretion involves the hormone ______ released by G cells.
The regulation of gastric secretion involves the hormone ______ released by G cells.
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Histamine is secreted by ______ cells in the gastric gland.
Histamine is secreted by ______ cells in the gastric gland.
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Gastric secretion is also regulated by the peptide released from nerves, known as ______.
Gastric secretion is also regulated by the peptide released from nerves, known as ______.
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Somatostatin, secreted by D cells, functions in ______ gastric secretion.
Somatostatin, secreted by D cells, functions in ______ gastric secretion.
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The gastric mucosal barrier protects the stomach from __________.
The gastric mucosal barrier protects the stomach from __________.
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Cell membranes of gastric mucosal cells are impermeable to __________ on the luminal side.
Cell membranes of gastric mucosal cells are impermeable to __________ on the luminal side.
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The HCO3–-rich mucus serves as a protective physical barrier and neutralizes __________ close to the gastric mucosa.
The HCO3–-rich mucus serves as a protective physical barrier and neutralizes __________ close to the gastric mucosa.
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The entire stomach lining is replaced in approximately __________ days.
The entire stomach lining is replaced in approximately __________ days.
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The main site for digestion and absorption of ingested food is the __________.
The main site for digestion and absorption of ingested food is the __________.
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The digestive processes involve the action of bile, pancreatic enzymes, and __________ enzymes.
The digestive processes involve the action of bile, pancreatic enzymes, and __________ enzymes.
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Microscopic finger-like projections in the small intestine are called __________.
Microscopic finger-like projections in the small intestine are called __________.
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Epithelial cells in the small intestine have numerous smaller projections called __________.
Epithelial cells in the small intestine have numerous smaller projections called __________.
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Three types of digestive enzymes are expressed on the membranes of microvilli: enteropeptidase, disaccharidases, and __________.
Three types of digestive enzymes are expressed on the membranes of microvilli: enteropeptidase, disaccharidases, and __________.
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The structure-function relationship of the small intestine includes permanent circular folds that increase surface area by __________.
The structure-function relationship of the small intestine includes permanent circular folds that increase surface area by __________.
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Study Notes
The Stomach
- J-shaped sac-like chamber, the most distensible part of the GI tract
- Stores ingested food
- Secretes gastric juice (acid, mucus, intrinsic factor, digestive enzymes - pepsin, lipase)
- Mixes food with gastric juice
- Pulverizes food, initiating protein and fat digestion
- Kills bacteria
- Moves food (chyme) into the duodenum at a controlled and steady rate
Stomach Anatomy
- Fundus: top portion
- Body: middle section, secretes mucus, pepsinogen, and HCl
- Antrum: bottom portion, secretes mucus, pepsinogen, and gastrin
- Pyloric sphincter: controls chyme release into the duodenum
- Lower esophageal sphincter controls food traveling down from the esophagus to the stomach
Gastric Mucosal Folds, Gastric Pits & Gastric Glands
- Gastric pits small openings in the stomach lining
- Gastric glands comprised of cells secreting substances like mucous, acid, and enzymes
- Mucous cells, chief cells, and parietal cells crucial components of gastric glands
Structure of Gastric Gland
- Acid, intrinsic factor, pepsinogen secretion sites
- Mucus layer for protection and neutralization of acid
- Cell migration and different cell types in the glands
The Stomach Mucosa and the Gastric Glands
- Surface epithelial cells (protection)
- Mucous cells (mucus)
- Chief cells (pepsinogen)
- Parietal cells (hydrochloric acid, intrinsic factor)
- Endocrine/Paracrine cells (hormones)
- Various stimuli trigger secretions
Gastric Glands - Important Products
- Hydrochloric acid (HCl): hydrolysis, sterilization, vitamin B12 absorption
- Intrinsic factor: vitamin B12 absorption
- Pepsinogen: protein digestion (converted to pepsin)
- Mucus, bicarbonate: gastroprotection (protection from acid)
- Trefoil factors: gastroprotection
- Histamine: regulation of gastric secretion
- Gastrin: regulation of gastric secretion
- Gastrin releasing peptide (GRP): regulation of gastric secretion
- Acetylcholine (ACh): regulation of gastric secretion
- Somatostatin: regulation of gastric secretion
Pepsinogen Activation
- Autocatalysis: pepsinogen converted to pepsin by HCl
- Pepsin: active protein-digesting enzyme
- Peptide fragments formed from protein digestion by pepsin.
Mechanism of Gastric HCI Secretion
- Cellular metabolism, producing hydrogen ions
- Active and secondary active transport produce HCl
- Carbonic anhydrase for the conversion of CO2 to bicarbonate ions.
Parietal Cell - Receptor Activation of the Proton Pump
- Receptors respond to histamine, acetylcholine, and gastrin
- cAMP and Ca++ pathways activate proton pumps (H+, K+ ATPase)
- These pumps pump hydrogen ions into the lumen, creating acid.
Control of Gastric Secretion
- Cephalic phase: triggered by factors before food entry (smell, thought)
- Gastric phase: factors arising from stomach food presence
- Intestinal phase: factors from food movement into the duodenum.
Digestive Processes From Small Intestine To Large Intestine
- Small intestine is the major site for digestion and absorption
- Its functions include secreting mucus and salt solutions and utilizing segmentation and peristalsis for mixing food
- Digestion depends on bile, pancreatic enzymes, and intestinal enzymes
- Absorption occurs mostly in the duodenum and jejunum( small intestine section)
Structure of Intestinal Villi
- Mucosal surface has circular folds increasing surface area 3-fold
- Microscopic finger-like projections (villi) increase surface area by 10-fold
- Epithelial cells have microvilli (brush border), increasing surface area 20-fold
- Digestive enzymes are located on the microvilli membranes (e.g., enteropeptidase, disaccharidases, aminopeptidases).
The Gastric Mucosal Barrier
- Cells lining the stomach are protected from acidity by cell membranes and tight junctions, HCO3--rich mucus, and tight junctions separating cells
- Frequent cell division (3 days) ensures a protective layer by continuously renewing cells
- Prostaglandins help in regulating acid secretion and producing alkaline mucous
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Description
Test your knowledge on the functions and components of the stomach with this quiz. It covers topics such as gastric secretions, pepsin role, and the digestion process. Perfect for students studying human anatomy and physiology.
