Chapter 3 Objectives Flashcards
Breaking food down through chewing and grinding, or moving it through the GI tract with peristalsis
Mechanical digestion
Breaking down food with enzymes or digestive juices
Chemical digestion
Substances that produce chemical changes or catalyze chemical reactions
Enzymes
The process by which digested nutrients move into the tissues where they can be transported and used by the body’s cells
Absorption
Organs of the digestive system (in order)
Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine
Mechanically digests food; first organ of the digestive system
Mouth
Passageway for the respiratory (air) and digestive tracts (food and beverages); second organ of the digestive system
Pharynx
Tube that extends from the throat to the stomach; mechanically digests food via peristalsis; moves food from pharynx to the stomach; third organ of the digestive system
Esophagus
Digestive organ that holds food after it’s been moved down the esophagus and before it’s propelled into the small intestine; mechanically digests food (churning); mixes bolus into chyme; enzymes and digestive juices are secreted to chemically digest food; fourth organ of the digestive system
Stomach
Comprised of the duodenum, jejunum, and ileum; most digestion and absorption occurs here; fifth organ of the digestive system
Small intestine
Consists of the cecum, appendix, ascending colon, transverse colon, descending colon, and rectum; chyme is turned into stool/feces; bacterial action on remaining waste; very little digestion; absorption of water, vitamins, and electrolytes; sixth organ of the digestive system
Large intestine
A pear shaped accessory organ located behind the liver; stores bile produced by the liver and secretes bile through the bile duct into the small intestine
Gallbladder
The largest gland of the body; aids in digestive activity and is responsible for metabolism of nutrients, detoxification of alcohol, and some nutrient storage
Liver
Accessory organ of digestion that produces hormones and enzymes; connected to the duodenum via the bile duct
Pancreas
The forward, rhythmic motion that moves food through the digestive system. A form of mechanical digestion because it influences motion, but does not add chemical secretions
Peristalsis
A ‘sloshing’ motion that thoroughly mixes chyme with the chemical secretions of the intestine
Segmentation
A specific reactant substance which a specific enzyme reacts with under specific conditions
Substrate
The substrate and enzyme that react together to form products
Reactants
The resulting substances formed after a chemical reaction
Products
Enzyme found in saliva and in the pancreas that breaks down carbohydrates
Amylase
Enzyme required to break down lactose
Lactase
Enzyme that breaks down lipids and fats
Lipase
Enzyme that breaks down proteins
Protease Pepsin Trypsin Chymotrypsin Carboxypeptidase
Enzyme found in the stomach?
Pepsin
Enzyme found in saliva?
Salivary amylase
Enzymes found in pancreas?
Pancreatic amylase
Trypsin
Chymotrypsin
Carboxypeptidase
Hormone produces in the stomach that stimulates digestive activities and increases motility and emptying
Gastrin
Hormone that increases hunger
Ghrelin
Hormone that tells the brain to stop eating
Leptin
Hormone that allows glucose to enter cells, decreasing blood sugar
Insulin
Hormone that increases blood sugar
Glucagon
Hormone secreted by the small intestine when acidic chyme enters the duodenum. Stimulates the pancreas to release bicarbonate ions to neutralize the HCl in chyme.
Secretin
A hormone released when the stomach is distended. It is associated with the feeling of satiation
Cholecystokinin
Small intestine’s role in digestion:
Absorption of nutrients
Surface area is tremendously increases with circular fold, villi, and microvilli (brush border)
Villi and Microvilli’s role in digestion:
Increase surface area in the small intestine for more absorption
Blood vessels transport nutrients to the liver
Circulatory system
Lymph vessels distribute larger fat molecules into the blood
Lymphatic system
A functional disorder that involves changes in colon rhythm
Irritable Bowel Syndrome (IBS)
An autoimmune disease of the small intestine that involves the inability to digest the protein gluten
Celiac disease
An inflammatory bowel disease involving inflammation and swelling of the intestines
Crohn’s disease
Cancer of the colon
Colon cancer
