NUTR 221 Advanced Nutrition Micronutrients

The digestive tract is a long tube responsible for breaking down food into smaller molecules that the body can absorb. It's made up of the oral cavity, esophagus, stomach, and small and large intestines.

Accessory organs are not part of the digestive tract itself, but they play crucial roles in digestion. They include the pancreas, liver, and gallbladder.

The mucosa is the innermost layer of the digestive tract and is directly in contact with food. It's made of the mucosal membrane, lamina propria, and muscularis mucosa.

The submucosa is found below the mucosa and is composed of connective tissue, blood vessels, lymphatic vessels, lymphoid tissue, and the submucosal plexus.

The muscularis externa is a layer of muscle tissue that helps move food through the digestive tract using peristalsis.

The serosa is the outermost layer of the digestive tract and is composed of flat mesothelial cells. It helps protect and lubricate the digestive system.

The oral cavity is the first part of the digestive tract, where food is initially broken down by chewing and saliva.

The esophagus is a muscular tube that connects the mouth to the stomach. It uses peristalsis to push food down towards the stomach.

A hormone produced by the stomach and small intestine that stimulates gastric acid secretion and pepsinogen secretion.

A hormone released by the small intestine and enteric nerves that stimulates gallbladder contraction, sphincter of Oddi relaxation, and pancreatic enzyme secretion.

A hormone released by the small intestine that stimulates pancreas juice secretion, diminishes gastric emptying, and diminishes gastric acid secretion.

A hormone produced by the stomach and intestines that stimulates gastric and intestinal motility between meals.

A hormone released by the small intestine that stimulates insulin secretion and may diminish gastric acid secretion.

A hormone produced by the small and large intestines that diminishes gastric acid secretion and gastric emptying.

A versatile hormone produced by the pancreas, stomach, and small intestine that inhibits various digestive activities.

A hormone released by the small and large intestines that stimulates insulin secretion, reduces digestive tract motility, and reduces gastric secretions.

Gastric glands are specialized epithelial cells in the stomach lining that secrete various substances involved in digestion. There are three main types: cardiac glands, oxyntic glands, and pyloric glands.

The cephalic phase of gastric secretion occurs before food even reaches the stomach. It's triggered by signals like the sight, smell, or taste of food. This phase involves the release of acetylcholine and gastrin, both of which stimulate gastric juice production.

The gastric phase is the second phase of gastric secretion. It begins when food enters the stomach. Distension of the stomach walls and the presence of food chemicals stimulate the release of gastrin, acetylcholine, and histamine, leading to increased gastric juice secretion.

The intestinal phase is the final phase of gastric secretion, occurring as chyme (partially digested food) enters the small intestine. It involves the release of hormones like cholecystokinin (CCK) and secretin, which have a regulatory effect on gastric secretions. CCK and secretin also influence the release of pancreatic juice and bile.

The pancreas is an important accessory organ with both endocrine and exocrine functions. It releases digestive enzymes (exocrine) and hormones like insulin and glucagon (endocrine).

Bile is a fluid produced by the liver, stored in the gallbladder, and released into the small intestine. It helps in the digestion and absorption of fats by emulsifying them, making them easier to digest.

The gallbladder is a small, pear-shaped organ attached to the liver. Its main function is to store and concentrate bile produced by the liver. Bile is released into the small intestine to aid in fat digestion.

Absorption is the process where nutrients from digested food are taken up from the small intestine and transferred into the bloodstream. It happens primarily in the duodenum, jejunum, and ileum.

Dietary fat intake slows down the rate at which food leaves the stomach and enters the small intestine.

Paracrine signaling involves communication between nearby cells, while neurocrine signaling uses neurotransmitters to send messages along nerves.

Ghrelin is a hormone that stimulates appetite, while leptin signals fullness and reduces hunger.

DRIs are a set of nutrient reference values for different stages of life and genders. EAR is the average daily intake to meet the needs of 50% of individuals. RDA is the recommended intake to meet the needs of nearly all healthy individuals.

The UL (Tolerable Upper Intake Level) is the maximum daily intake that is not expected to pose any health risks to most individuals.