Digestive System

• the pathway of the digestive system starts from the food, mouth, esophagus, stomach, small intestine, large intestine, rectum and anus
• the function of the digestive system is to help convert large food molecules into simpler molecules or monomers that can be absorbed and used by the cells of the body
• the teeth do the mechanical work of digestion by cutting, tearing, and crushing foods
• the mouth is the first step in digestion and increases the surface area of food
• the salivary gland helps moisten food and make it easier to chew
• the chemical digestion process breaks down bonds in starches and releases sugars
• lysozyme is an enzyme that fights infection by breaking down cell walls of many bacteria
• the salivary gland contains lysozyme which fights infection by breaking down cell walls of bacteria
• the esophagus is a long tube of smooth muscle that connects the pharynx with the stomach
• bolus is the term for chewed clump of food
• the use of the tongue and muscles push bolus down the throat
• the epiglottis closes over the trachea to keep food out
• the esophagus carries food to the stomach
• peristalsis is the contractions of smooth muscles. it squeezes food thru the esophagus into the stomach
• reverse peristalsis causes vomiting
• the cardiac sphincter closes and prevents stomach contents from moving back up the esophagus
• the stomach is a large sac of smooth muscle
• the gastric glands in the stomach secretes substances
• mucus lubricates and protects the stomach wall
• hydrochloric acid or pepsin breaks down proteins
• duodenum is the first of the 3 parts of the small intestine
• most of the chemical digestion and absorption of nutrients occurs in the small intestine
• the small intestines mixes with fluids and enzymes from pancreas and liver
• the substances absorbed in the large intestine are vitamins and water
• the large intestine is also known as the colon
• the primary function of the large intestine is to remove water from the undigested material
• water is absorbed across the wall of the large intestine
• the concentrated waste material that remains passes through the rectum and is eliminated from the body
• the rectum is a chamber that begins at the end of the large intestine, followed by the sigmoid colon, and ends at the anus
• the anus is the opening at the far end of the digestive tract through which stool leaves the body
• the mouth is the entry point of food in the body
• chemical digestion is the main type of digestion in the stomach
• the liver is located above and to the right of the stomach
• bile is produced in the liver which is a fluid loaded with lipids and salts
• bile acts as a detergent, dissolving droplets of fats from food. it is stored in the gallbladder
• the pancreas produces hormones that regulate blood sugar levels
• the pancreas produces enzymes that break down carbs, proteins, lipids, and nucleic acids
• sodium bicarbonate is a base which neutralizes stomach acid in order for enzymes to be effective
• the physical change that happens in the mouth is when food is torn into smaller pieces by the teeth and when food is mixed with saliva
• the chemical change that happens in the mouth is when saliva breaks down carbohydrates