Animal Nutrition and the Digestive System
Terms
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- chyme
- A partially digested mass of food that enters the small intestine
- ileum
- The last of three sections of the small intestine primarily involved in the absorption of nutrients and water
- Bile
- A mixture of substances produced by the liver and stored in the gallblatter. Contains no digestive enzymes, but bile salts, which aid in digestion and absoption of fats
- Small intestine and sections
- Organ where vast majority of chemical disgestion and absoption of biomolecules takes place. 3 areas: duodenum (1st), jejunum (2nd), ileum. More thn 6ft long
- duodenum
- The first section of the small intestine, where acid chyme from the stomach mixes with digestive juices from the pancreas, liver, gallbladder, and gland cells of the intestinal wall
- pyloric sphincter
- a thick band of muscles at the end of the stomach (pylorus). muscle that regulates the passage of chyme into the small intestine.
- CCK (cholecystikinin)
- a hormone released by small intestine cells in the duodenum. Stimulates the release of amylas, lipas, and bile. CCK is released due to fat-digestion products. Controls the negative feedback loop for fat breakdown
- Extracellular disgestion
- The breakdown of food outside cells - occurs in most animals
- Secretin definition
- a hormone that stimulates the release of biocarbonate ions from the pancreas if too much cyme enter the duodenum at once.
- Secretin controls...
- negative feedback loop for pH control of chyme
- Gastrin defintion
- a hormone that stimulates the release of HCL and pepsinogen to further breakdown protein and amino acids in the stomach before they enter the duodenum
- Gastrin controls...
- the negative feedback loop for protein breakdown
- villi
- large circular folds that protude into the interior of the intestine. made up of epithelial cells
- microvilli
- microscopic appendages of a villus cell that are exposed to the intestinal lumen. increases surface area and is an adaption that increastes the rate of nutritional absorption
- large intestine
- also known as the colon. main job is to reabsorb water and salts.
- chylomicrons
- Small intracellular globules composed of fats that are mixed with cholesterol and coated with special proteins
- What are the 3 sets of salivary glands in humans?
- parotid (below ear), submaxillary (below the upper jaw), and sublingual (below the tongue)
- Intracellular digestion
- The joining of food vacuoles and lysosome to allow chemical digestion to occur within the cytoplasm of a cell
- Pepsinogen
- The inactivated form of pepsin produced by specialized cells called chief cells located in gastric pits. Converted to pepsin in the lumen of the stomach.
- gastrovascular cavities
- An extensive pouch that serves as the site of extracellular digestion and a passageway to disperse materials throughout most of an animal's body. In animals with simple body plans: hydras, Paramecium
- bolus
- a lubricated ball of chewed food
- Saliva: definition, contains
- a fluid rich in ions and containing some enzymes that assist in wetting and lubricating food particles. Contains salivary amylase, an enymze that hydrolzyes starch
- Saliva: definition,
- a fluid rich in ions and containing some enzymes that assist in wetting and lubricating food particles. Contains salivary amylas, an enyze that hydrolzyes starch
- Gastric Juice
- a mixture of mucus, HCL, and pesinogen that are secreted by the epithelium tissues in the stomach
- Pepsin
- an enzyme that begins the hydrolysis of protein by splitting the polypeptide chains of proteins into smaller units
- lacteals
- A tiny lymph vessel extending into the core of an intestinal villus and serving as the destination for absorbed chylomicrons
- emulsification
- The process that keeps tiny fat droplets from coalescing. performed by bile salts. permitts fat to pass directly into intestinal cells and into the bloodstream
- gastrovascular cavity
- An extensive pouch that serves as the site of extracellular digestion and a passageway to disperse materials throughout most of an animal's body