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Questions and Answers
What is the primary function of peristalsis in the digestive system?
What is the primary function of peristalsis in the digestive system?
Which type of movement in the digestive system promotes solubilization and absorption of food?
Which type of movement in the digestive system promotes solubilization and absorption of food?
What type of muscle contraction is involved in segmentation?
What type of muscle contraction is involved in segmentation?
Which phase of gastric secretion is triggered by the presence of acid, carbohydrates, lipids, and undigested proteins in the duodenum?
Which phase of gastric secretion is triggered by the presence of acid, carbohydrates, lipids, and undigested proteins in the duodenum?
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What is the role of gastrointestinal hormones in the intestinal phase of gastric secretion?
What is the role of gastrointestinal hormones in the intestinal phase of gastric secretion?
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Which movement in the digestive system results in slow food propulsion?
Which movement in the digestive system results in slow food propulsion?
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What process do small aquatic sessile animals utilize to obtain food?
What process do small aquatic sessile animals utilize to obtain food?
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Which process involves the engulfing of larger food particles?
Which process involves the engulfing of larger food particles?
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What mechanism is used to take up smaller nutrient particles?
What mechanism is used to take up smaller nutrient particles?
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What happens after the food particles are engulfed or taken up by the cell?
What happens after the food particles are engulfed or taken up by the cell?
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What is the main difference between phagocytosis and pinocytosis?
What is the main difference between phagocytosis and pinocytosis?
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Which process is a more active form of feeding?
Which process is a more active form of feeding?
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What is the role of HCO3- secreted by Brunner's glands in the duodenum?
What is the role of HCO3- secreted by Brunner's glands in the duodenum?
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Which cells secrete somatostatin and inhibit pepsinogen, HCl, and gastrin release?
Which cells secrete somatostatin and inhibit pepsinogen, HCl, and gastrin release?
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Which type of fluid secreted by the mammalian small intestine contains enzymes that aid in digestion?
Which type of fluid secreted by the mammalian small intestine contains enzymes that aid in digestion?
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What is the function of the crypts of Lieberkühn in the small intestine?
What is the function of the crypts of Lieberkühn in the small intestine?
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Which of the following substances is not secreted by the mammalian small intestine?
Which of the following substances is not secreted by the mammalian small intestine?
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What is the role of the alkalinity provided by Brunner's glands in the duodenum?
What is the role of the alkalinity provided by Brunner's glands in the duodenum?
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What is the primary function of the salivary glands in the digestive system?
What is the primary function of the salivary glands in the digestive system?
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What is the main function of the midgut in the digestive system?
What is the main function of the midgut in the digestive system?
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What type of food generally requires a longer period of digestion?
What type of food generally requires a longer period of digestion?
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What is the main function of the hindgut in the digestive system?
What is the main function of the hindgut in the digestive system?
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Which division of the alimentary canal is responsible for receiving ingested material?
Which division of the alimentary canal is responsible for receiving ingested material?
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What is the primary function of the foregut in the digestive system?
What is the primary function of the foregut in the digestive system?
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Which of the following is not a function of the tongue in the digestive system?
Which of the following is not a function of the tongue in the digestive system?
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What is the main function of the esophagus in the digestive system?
What is the main function of the esophagus in the digestive system?
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What is the main function of the crop in the digestive system?
What is the main function of the crop in the digestive system?
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Which of the following is not a function of saliva in the digestive system?
Which of the following is not a function of saliva in the digestive system?
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Which hormone is synthesized and released by I-cells in the duodenum in response to fat and protein-rich chyme?
Which hormone is synthesized and released by I-cells in the duodenum in response to fat and protein-rich chyme?
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Which hormone is primarily responsible for inducing insulin secretion from the pancreas in response to carbohydrates and fat-rich chyme?
Which hormone is primarily responsible for inducing insulin secretion from the pancreas in response to carbohydrates and fat-rich chyme?
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Which enzymes function at the brush border membrane in the small intestine, rather than directly in the lumen?
Which enzymes function at the brush border membrane in the small intestine, rather than directly in the lumen?
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Which hormone is synthesized and released by S-cells in the duodenum when exposed to the acidic contents of an emptying stomach?
Which hormone is synthesized and released by S-cells in the duodenum when exposed to the acidic contents of an emptying stomach?
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Which hormone is synthesized and released by enteroendocrine cells in the duodenum in response to fat-rich chyme?
Which hormone is synthesized and released by enteroendocrine cells in the duodenum in response to fat-rich chyme?
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Which part of the digestive system acts to store the remnants of the digested food, reabsorbs inorganic ions, and excess water into the circulatory system, and defecates faeces?
Which part of the digestive system acts to store the remnants of the digested food, reabsorbs inorganic ions, and excess water into the circulatory system, and defecates faeces?
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Which hormone is commonly referred to as glucose-dependent insulinotropic peptide (GIP) due to its role in inducing insulin secretion from the pancreas?
Which hormone is commonly referred to as glucose-dependent insulinotropic peptide (GIP) due to its role in inducing insulin secretion from the pancreas?
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Which part of the digestive system conducts, stores, and digests ingested material?
Which part of the digestive system conducts, stores, and digests ingested material?
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Which enzyme is responsible for stimulating the pancreatic enzyme release for protein digestion?
Which enzyme is responsible for stimulating the pancreatic enzyme release for protein digestion?
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Which hormone stimulates the secretion of salt and water into the duodenum and HCO3- secretion by the pancreas?
Which hormone stimulates the secretion of salt and water into the duodenum and HCO3- secretion by the pancreas?
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Study Notes
Feeding Mechanisms
- Feeding mechanisms include peristalsis, mixing movements, and segmentation to facilitate digestion and absorption.
- Peristalsis involves the contraction and relaxation of circular and longitudinal smooth muscles to propel the bolus forward.
- Segmentation involves the alternate contraction and relaxation of circular smooth muscles to mix food and digestive enzymes.
Digestive System Anatomy and Function
- The digestive system consists of four main divisions: headgut, foregut, midgut, and hindgut.
- The headgut receives ingested material, the foregut conducts, stores, and digests ingested material, the midgut digests and absorbs nutrients, and the hindgut absorbs water and expels waste.
Midgut Motility
- Peristalsis involves the contraction and relaxation of adjacent segments of the tract to propel the bolus forward.
- Segmentation involves the alternate contraction and relaxation of segments of the tract to mix food and digestive enzymes.
Intestinal Phase of Secretion
- The intestinal phase of secretion involves the release of gastrointestinal hormones in response to the presence of chyme in the duodenum.
- Hormones released include cholecystokinin (CCK), secretin, vasoactive intestinal peptide (VIP), and gastric inhibitory peptide (GIP).
- These hormones regulate gastric motility, acid secretion, and pancreatic enzyme release.
Endocytosis
- Endocytosis is a more active form of feeding that involves the engulfment of food particles by the cell.
- There are two types of endocytosis: phagocytosis (engulfment of larger particles) and pinocytosis (engulfment of smaller particles).
Filter or Suspension Feeding
- Filter or suspension feeding involves the use of cilia or flagella to generate water currents that bring in nutrients.
- This type of feeding is used by small aquatic sessile animals.
Digestive Systems
- Digestive systems combine features of continuous-flow and plug-flow reactors.
- The design of the digestive system must match the quality of food that the animal eats.
- Herbivores have a longer digestive system to accommodate lower quality food, while carnivores have a shorter digestive system to accommodate high-quality food.
Food Quality and Digestion
- Food quality affects the time required for digestion.
- High-quality food requires less energy and time for digestion, while low-quality food requires more energy and time.
- Digestive systems are adapted to the type of food an animal eats.
General Plan of Vertebrate Digestive System
- The vertebrate digestive system consists of the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
- Accessory digestive organs include salivary glands, exocrine pancreas, and the biliary system.
Headgut
- The headgut receives ingested material and consists of the mouth, oral cavity, pharynx, teeth, bills/beak, tongue, and salivary glands.
- The tongue assists in mechanical digestion and swallowing, and contains chemoreceptors (taste buds).
- Salivary glands produce saliva that lubricates food, begins digestion of carbohydrates, and has antibacterial properties.
Salivary Glands
- There are three major salivary glands: sublingual, submandibular, and parotid.
- Saliva contains 99.5% water, 0.5% electrolytes and proteins, including amylase, lingual lipase, and mucin.
- Salivary secretion is a two-stage process involving acinar cells and duct cells.
Foregut
- The foregut conducts, stores, and digests ingested material.
- The primary organs of the foregut are the pharynx, esophagus, and crop.
Hindgut
- The hindgut absorbs water and expels waste.
- The hindgut in vertebrates consists of the large intestine or colon (including the cecum) and the rectum.
- The hindgut terminates in a cloaca in many vertebrates.
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Description
Explore the feeding mechanisms of tapeworms, focusing on how small molecules like amino acids are taken in by transport mechanisms, and how larger molecules are absorbed through bulk processes such as endocytosis. Learn about phagocytosis and the active form of feeding involved in this process.
