The Physiology of the Digestive System

**Amylase #

** A type of enzyme that breaks down starches into simple sugars during digestion. Found in saliva and pancreatic juice.

**Bile #

** A digestive juice produced by the liver and stored in the gallbladder. It helps to break down fats in the small intestine.

**Chyme #

** The partially digested food that is passed from the stomach into the small intestine.

**Esophagus #

** The tube that connects the throat to the stomach, allowing food to pass from the throat to the stomach during swallowing.

**Gastric juice #

** The digestive juice produced by the stomach, which contains hydrochloric acid, pepsin, and mucus.

**Gastroparesis #

** A medical condition where the stomach is unable to empty itself of food in a normal manner.

**HCl (hydrochloric acid) #

** A strong acid produced by the stomach, which helps to break down proteins and kill bacteria in food.

**Intestinal villi #

** Finger-like projections that line the walls of the small intestine, increasing the surface area for absorption of nutrients.

**Lactase #

** An enzyme that breaks down lactose, a sugar found in milk and dairy products, into simpler sugars.

**Mucus #

** A slippery substance produced by the stomach and other parts of the digestive system, which protects the lining of the digestive tract.

**Pancreas #

** A gland located behind the stomach, which produces digestive enzymes and hormones such as insulin.

**Peristalsis #

** The wave-like contractions of the muscles in the walls of the digestive tract, which help to move food along.

**Pepsin #

** A digestive enzyme produced by the stomach, which breaks down proteins into smaller peptides.

**Small intestine #

** The longest part of the digestive tract, where most of the digestion and absorption of nutrients takes place.

**Vagus nerve #

** The tenth cranial nerve, which carries signals between the brain and the digestive system, controlling many of its functions.

**Absorption #

** The process by which nutrients are taken up from the digestive tract into the bloodstream.

**Bacteria #

** Microorganisms that live in the digestive tract and play a role in digestion and the immune system.

**Bile salts #

** Compounds found in bile that help to break down fats.

**Bradykinin #

** A hormone produced by the body in response to injury or stress, which can cause pain, inflammation, and relaxation of smooth muscle.

**Cholecystokinin (CCK) #

** A hormone produced by the intestines in response to food, which stimulates the release of bile and pancreatic enzymes.

**Dipeptidases #

** Enzymes that break down dipeptides, which are formed when pepsin breaks down proteins in the stomach.

**Duodenum #

** The first part of the small intestine, where most of the chemical digestion of food takes place.

**Enzyme #

** A protein that speeds up a chemical reaction in the body.

**Gastrin #

** A hormone produced by the stomach in response to food, which stimulates the release of gastric juice.

**Gastrointestinal (GI) tract #

** The digestive system, consisting of the mouth, esophagus, stomach, small intestine, large intestine, and anus.

**Gastroesophageal reflux disease (GERD) #

** A medical condition where stomach acid flows back into the esophagus, causing symptoms such as heartburn and acid reflux.

**Gliadin #

** A protein found in wheat and other grains, which can cause an immune response in people with celiac disease.

**Histamine #

** A compound released by the body in response to injury or allergies, which can cause symptoms such as itching, swelling, and pain.

**Inflammatory bowel disease (IBD) #

** A group of medical conditions that cause inflammation in the digestive tract, including Crohn's disease and ulcerative colitis.

**Irritable bowel syndrome (IBS) #

** A medical condition that causes symptoms such as abdominal pain, bloating, and changes in bowel habits.

**Large intestine #

** The last part of the digestive tract, where water and electrolytes are absorbed and feces are formed.

**Leptin #

** A hormone produced by fat cells, which helps to regulate appetite and energy balance.

**Maltase #

** An enzyme that breaks down maltose, a sugar found in grains, into simpler sugars.

**Motilin #

** A hormone produced by the digestive system, which stimulates muscle contractions in the stomach and small intestine.

**Neuropeptide Y #

** A hormone produced by the nervous system, which stimulates appetite and reduces energy expenditure.

**Nutrient #

** A substance in food that is necessary for the body's growth, repair, and maintenance.

**Peptide #

** A compound formed by the linking of two or more amino acids.

**Perianal #

** The area around the anus.

**Secretin #

** A hormone produced by the small intestine, which stimulates the release of bicarbonate and pancreatic enzymes.

**Serotonin #

** A hormone produced by the nervous system, which regulates mood, appetite, and sleep.

**Somatostatin #

** A hormone produced by the digestive system and nervous system, which inhibits the release of other hormones and enzymes.

**Villous atrophy #

** A condition where the intestinal villi are damaged or destroyed, leading to malabsorption and malnutrition.

**Zollinger #

Ellison syndrome:** A medical condition where the stomach produces too much acid, leading to ulcers and other digestive symptoms.