Podcast
Questions and Answers
Which of the following has an inhibitory effect on gastric emptying?
Which of the following has an inhibitory effect on gastric emptying?
What are some of the factors influencing digestion and absorption?
What are some of the factors influencing digestion and absorption?
Which of the following hormones is NOT mentioned as a regulatory peptide affecting gastric emptying?
Which of the following hormones is NOT mentioned as a regulatory peptide affecting gastric emptying?
Which factor does NOT contribute to adequate nourishment from the gastrointestinal tract?
Which factor does NOT contribute to adequate nourishment from the gastrointestinal tract?
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How is the Recommended Dietary Allowance (RDA) calculated from the Estimated Average Requirement (EAR)?
How is the Recommended Dietary Allowance (RDA) calculated from the Estimated Average Requirement (EAR)?
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Which of the following is NOT a part of the digestive tract?
Which of the following is NOT a part of the digestive tract?
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What role do the gastric juices serve in the stomach?
What role do the gastric juices serve in the stomach?
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Which of the following structures is part of the mucosa layer of the digestive tract?
Which of the following structures is part of the mucosa layer of the digestive tract?
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During swallowing, which type of muscle contraction is responsible for moving the bolus through the esophagus?
During swallowing, which type of muscle contraction is responsible for moving the bolus through the esophagus?
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What is the primary function of the small intestine?
What is the primary function of the small intestine?
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Which accessory organ produces bile that is essential for fat digestion?
Which accessory organ produces bile that is essential for fat digestion?
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What type of tissue primarily makes up the submucosa layer of the digestive tract?
What type of tissue primarily makes up the submucosa layer of the digestive tract?
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Which structural feature of the small intestine increases its surface area for nutrient absorption?
Which structural feature of the small intestine increases its surface area for nutrient absorption?
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What is the primary function of gastrin?
What is the primary function of gastrin?
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Which hormone is associated with stimulating gallbladder contraction?
Which hormone is associated with stimulating gallbladder contraction?
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Which hormone primarily diminishes gastric acid secretion?
Which hormone primarily diminishes gastric acid secretion?
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What effect does somatostatin have on gastric and intestinal activities?
What effect does somatostatin have on gastric and intestinal activities?
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Which hormone promotes insulin secretion from the pancreas?
Which hormone promotes insulin secretion from the pancreas?
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What is the main production site of motilin?
What is the main production site of motilin?
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Which hormone diminishes gastric motility and secretion?
Which hormone diminishes gastric motility and secretion?
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Which factor initiates peristaltic waves for digestion?
Which factor initiates peristaltic waves for digestion?
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What triggers the release of somatostatin after food has left the stomach?
What triggers the release of somatostatin after food has left the stomach?
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Which of the following glands primarily secretes digestive enzymes into the duodenum?
Which of the following glands primarily secretes digestive enzymes into the duodenum?
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What role does bile play in digestion?
What role does bile play in digestion?
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Which process is NOT a method of absorption in the intestines?
Which process is NOT a method of absorption in the intestines?
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What primarily absorbs sodium and water in the colon?
What primarily absorbs sodium and water in the colon?
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Which organ is responsible for synthesizing bile?
Which organ is responsible for synthesizing bile?
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What is a primary function of the myenteric plexus in the digestive system?
What is a primary function of the myenteric plexus in the digestive system?
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What is the primary function of goblet cells in the colon?
What is the primary function of goblet cells in the colon?
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Study Notes
NUTR 221 Advanced Nutrition Micronutrients
- Course taught by Dr. Christine M. Mills (she/her)
- Slides cannot be shared or reproduced without permission
- Adapted from slides by Dr. Brian Bandy, PhD
Dr. Mills' Background
- Registered dietitian with experience in primary care, community health, and public health
- Provost's Interdisciplinary Postdoctoral Fellow at the University of Waterloo
- PhD in Aging & Health from Queen's University
- MPH in Nutrition & Dietetics from the University of Toronto
- BSc in Applied Human Nutrition and BEng in Biological Engineering from the University of Guelph
- Military spouse
- Owner of Sphynx cats
- Runner
- Group fitness instructor
Learning Objectives
- Identify digestive tract organs and their roles in nutrient digestion and absorption
- Describe secretions released by digestive organs, including accessory organs, and factors influencing their release
- Describe structural features of the small intestine that facilitate nutrient absorption
- Describe the roles of the nervous system and regulatory peptides in regulating the digestive process
Digestive Tract Structures
- Main structures: Oral cavity, esophagus, stomach, small intestines, and large intestines
- Accessory organs: Pancreas, liver, and gallbladder
Layers of the Lumen
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Mucosa: Mucosal membrane, lamina propria, muscularis mucosa
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Submucosa: Connective tissue, blood, lymphatic vessels, lymphoid tissue, submucosal plexus
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Muscularis externa: Smooth muscles
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Serosa: Flat mesothelial cells
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Oral Cavity: Includes mouth and pharynx, salivary glands (parotid, submandibular, sublingual). Saliva contains enzymes which aid in digestion
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Esophagus: Transports food from the oral cavity to the stomach
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Swallowing: Voluntary, pharyngeal, esophageal
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Peristalsis: Moves food through the digestive tract
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Gastroesophageal sphincter Regulates the passage of food from esophagus to stomach
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Disorders: GERD
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The Stomach: Four main regions: cardia, fundus, body, antrum.
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Stomach muscles: Mix food with gastric juices to form chyme
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Gastric glands Cardiac, oxyntic, pyloric
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Regulation of gastric secretions: Three phases: before food reaches stomach (acetylcholine, gastrin); once food is in stomach (stomach distension enhances secretions); after food leaves stomach (reduction in chyme volume and pH trigger release of somatostatin)
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The Pancreas: Ductless endocrine cells secrete hormones into the blood, a crucial part of the digestive process. Acinar exocrine cells produce digestive enzymes, and pancreatic juice contains water, electrolytes, bicarbonate, and digestive enzymes
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The Liver: Lobes made of lobules, portal circulation, bile canaliculi. The liver synthesizes bile composed of bile acids, salts, cholesterol, phospholipids, and bile pigments in an alkaline solution. Bile aids in lipid digestion by emulsifying lipid globules in the small intestine.
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The Gallbladder: Concentrates and stores bile. Recirculation of bile involves the reabsorption of bile salts in the ileum.
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The Absorptive Process: Begins in duodenum and continues through jejunum and ileum. Methods include diffusion, facilitated diffusion, active transport, and pinocytosis/endocytosis
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Small Intestine Structures: Villi and microvilli structures increase surface area, enhancing absorption. These include cell membranes, tight junctions, desmosomes, and other structural components crucial for absorption.
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The Colon (Large Intestine): Contracts to mix materials. Proximal colonic mucosal cells absorb sodium and water. Influenced by hormones, dehydrates materials. Goblet cells secrete mucus and bicarbonate is also part of the secretion
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Coordination and Regulation of the Digestive Process: Neural regulation is by the myenteric and submucosal plexuses. Regulatory peptides (hormones and paracrines) play crucial roles.
Dietary Reference Intakes (DRIs)
- Important for establishing an understanding of adequate amounts of nutrients in diet
- Risk of inadequacy and excess are important considerations for setting appropriate intake ranges.
- EAR is the estimated average amount of a nutrient required for good health for the average person.
- RDA is calculated from EAR adding a safety factor
- UL is the highest amount of a nutrient that will not cause toxicity in most healthy people
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Description
This quiz explores key concepts in advanced nutrition, focusing on micronutrients and their roles in the digestive system. Participants will identify digestive organs, secretions, and structural features of the small intestine that aid in nutrient absorption. Prepare to deepen your understanding of nutritional science!
