Podcast
Questions and Answers
Which of the following processes is NOT one of the six basic digestive processes?
Which of the following processes is NOT one of the six basic digestive processes?
What is the main function of the small intestine?
What is the main function of the small intestine?
Which of these structures connects the pharynx to the stomach?
Which of these structures connects the pharynx to the stomach?
Which of the following structures is not part of the large intestine?
Which of the following structures is not part of the large intestine?
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Where is the Sphincter of Oddi located?
Where is the Sphincter of Oddi located?
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What is the function of the internal anal sphincter?
What is the function of the internal anal sphincter?
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Which part of the GI tract is responsible for the absorption of water and alcohol?
Which part of the GI tract is responsible for the absorption of water and alcohol?
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Which sphincter connects the oesophagus to the stomach?
Which sphincter connects the oesophagus to the stomach?
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Which hormone is stimulated by the distension of the stomach and the presence of partially digested proteins?
Which hormone is stimulated by the distension of the stomach and the presence of partially digested proteins?
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What major effect does cholecystokinin (CCK) have?
What major effect does cholecystokinin (CCK) have?
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Which hormone inhibits gastric emptying and promotes the feeling of satiety?
Which hormone inhibits gastric emptying and promotes the feeling of satiety?
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Which part of the digestive system experiences segmental contractions?
Which part of the digestive system experiences segmental contractions?
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The cephalic phase of digestion is known for which primary action?
The cephalic phase of digestion is known for which primary action?
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What triggers the secretion of secretin?
What triggers the secretion of secretin?
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During which phase of digestion do neural and hormonal mechanisms operate?
During which phase of digestion do neural and hormonal mechanisms operate?
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Which hormone promotes the secretion of pancreatic juice rich in HCO3-?
Which hormone promotes the secretion of pancreatic juice rich in HCO3-?
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Which cell in the stomach secretes hydrochloric acid?
Which cell in the stomach secretes hydrochloric acid?
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What are the permanent ridges in the mucosa and submucosa of the small intestine called?
What are the permanent ridges in the mucosa and submucosa of the small intestine called?
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Which part of the large intestine is directly connected to the ileum?
Which part of the large intestine is directly connected to the ileum?
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Which drug class includes Omeprazole?
Which drug class includes Omeprazole?
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What is the function of G cells in the stomach?
What is the function of G cells in the stomach?
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What is the role of Paneth cells in the small intestine?
What is the role of Paneth cells in the small intestine?
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Which layer of muscle is unique to the stomach among the listed options?
Which layer of muscle is unique to the stomach among the listed options?
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Which cell type in the stomach secretes pepsinogen?
Which cell type in the stomach secretes pepsinogen?
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What is the primary function of absorptive epithelium in the large intestine?
What is the primary function of absorptive epithelium in the large intestine?
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Which salivary gland primarily produces salivary amylase?
Which salivary gland primarily produces salivary amylase?
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What is the role of bile salts such as deoxychoilic acid?
What is the role of bile salts such as deoxychoilic acid?
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Which enzyme in pancreatic juice is responsible for digesting starch?
Which enzyme in pancreatic juice is responsible for digesting starch?
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Which cells in the pancreas are responsible for endocrine functions?
Which cells in the pancreas are responsible for endocrine functions?
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What inhibits the secretion of saliva?
What inhibits the secretion of saliva?
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What is the daily volume of pancreatic juice secretion?
What is the daily volume of pancreatic juice secretion?
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What is the function of the myenteric plexus in the enteric nervous system?
What is the function of the myenteric plexus in the enteric nervous system?
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What does parasympathetic stimulation do to the gastrointestinal function?
What does parasympathetic stimulation do to the gastrointestinal function?
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Which cells in the pancreas are exocrine cells?
Which cells in the pancreas are exocrine cells?
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Study Notes
The Large Intestine
- No circular folds or villi in the large intestine
- Mucosa is mostly an absorptive epithelium, with microvilli and interspersed goblet cells that produce mucus
Salivary Glands
- Three main salivary glands: parotid, sublingual, and submandibular
- Pancreas has both endocrine and exocrine functions
- Liver is involved in the excretion of bile pigments and bile salts
Saliva
- Constituents of saliva: mostly water (99.5%), ions, dissolved gases, urea, uric acid, immunoglobulin A, lysozyme, and salivary amylase
- Not all salivary glands produce the same type of saliva
- Submandibular and sublingual glands produce mucin-rich saliva, while the parotid gland produces salivary amylase
Control of Salivation
- Controlled by the autonomic nervous system
- Parasympathetic stimulation promotes secretion of more saliva, while sympathetic stimulation decreases salivation
Pancreas
- Lies posterior to the greater curvature of the stomach
- Pancreatic juice is secreted into the pancreatic duct and accessory duct, which then enters the small intestine
- Pancreatic duct joins the common bile duct and enters the duodenum at the hepatopancreatic ampulla
- Histology: 99% of cells are acini, with exocrine cells secreting pancreatic juice and endocrine cells secreting hormones
Control of Gastrointestinal Function
- Enteric nervous system (ENS) is an intrinsic set of nerves that acts as the "brain of the gut"
- ENS extends from the esophagus to the anus and has two plexuses: myenteric plexus (controls GI tract motility) and submucosal plexus (controls secretions)
- Autonomic nervous system is an extrinsic set of nerves that can stimulate or inhibit the ENS
Pancreatic Juice
- Volume: 1200-1500ml daily
- Constituents: mostly water, sodium bicarbonate, and enzymes (pancreatic amylase, proteolytic enzymes, pancreatic lipase, and ribonuclease and deoxyribonuclease)
Organization of the Enteric Nervous System
- Consists of the myenteric plexus, submucosal plexus, interneurons, motor neurons, and longitudinal and circular smooth muscle layers of the muscularis
Digestive Processes
- Six basic processes involved in digestion: ingestion, secretion, motility, digestion, absorption, and defecation
The 11 Major Structures of the GI Tract
- Oesophagus, stomach, duodenum, jejunum, ileum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus
Overview of GI Tract Functions
- Mouth: bite, chew, swallow
- Pharynx and oesophagus: transport
- Stomach: mechanical disruption; absorption of water and alcohol
- Small intestine: chemical and mechanical digestion and absorption
- Large intestine: absorb electrolytes and vitamins (B and K)
- Rectum and anus: defecation
Major Valves (Sphincters)
- Small intestine: sphincter of Oddi
- Large intestine: ileocaecal sphincter, internal anal sphincter, and external anal sphincter
Oesophagus
- Collapsible, muscular tube that lies posterior to the trachea and connects the pharynx to the stomach
Stomach
- Internal anatomy: esophagus, duodenum, pylorus, pyloric sphincter, fundus, cardia, body, rugae of mucosa, lesser curvature, greater curvature, pyloric canal, and pyloric antrum
- Major valves: upper oesophageal sphincter, lower oesophageal sphincter, cardiac sphincter, and pyloric sphincter
- Histology: gastric pits, surface mucous cell, lamina propria, mucous neck cell, parietal cell, chief cell, gastric glands, lymphatic nodule, muscularis mucosae, and enteric neurons
- Gastric glands and cell types: surface mucous cells, mucous neck cells, parietal cells, chief cells, and G cells
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Description
This quiz covers the structure and functions of the large intestine, salivary glands, and saliva. Learn about the special features of each component and their roles in the digestive process.
