We are now visiting a key factor of the digestive system, all the many parts behind the job and their purposes. While we are here, we will specifically see what the digestive system does and how all these parts work together as a whole.
Parts and Purposes
Types of Digestion
Mechanical Digestion: The physical break down of larger food into small pieces of food, by churning and contracting.
Chemical Digestion: The chemical break down of food molecules into smaller food molecules.
Chemical Digestion: The chemical break down of food molecules into smaller food molecules.
Mouth
Mouth: The mouth performs both mechanical and chemical digestion. The mouth is where digestion starts. Your mouth is full of many different sets of teeth; molars, bicuspid, and cuspids. When you first chew your food, your teeth crush and tear apart your food, into moisten pasted that can be swallowed. Your teeth are very durable; they are protected by a special enzyme that makes them stronger than most bone. The mouth also contains Sylva which is produced in the salivary glands, which begins the process of chemical digestion. Enzymes break down bonds in your food.
Esophagus
Esophagus: Your esophagus is you “food tube.” Smooth muscles contract bringing the food down to the stomach (this is mechanical digestion). Once the food is in the stomach a ring of muscles call the cardiac sphincter close. This prevents food from coming back up the esophagus.
Stomach
Stomach: the stomach continues mechanical digestion. Muscles churn and contract and mix the food with stomach fluids making a substance called chyme. The lining of the stomach has 100000 gastric glands. These glands release substances that lubricate the walls, make mucus, or make hydrochloric acid. The hydrochloric acid activates a enzyme call pepsin (which works best in acidic environments.) This then begins protein digestion, in which pepsin breaks down proteins.
Pancreas and Liver
Pancreas: The pancreas produces hormones that regulate blood sugar levels. Enzymes brake down carbohydrates, protein, lipids and nucleic acid. This makes soduimnicarbonate (a base) that neutralizes stomach acid, so other enzymes and still function
Liver: The liver is just above the stomach. It makes Bile a fluid made of lipids and salts. Bile dissolves fat in fatty foods. Next enzymes reach the fat molecules, and break them down. Bile is stored in the gall bladder.
Liver: The liver is just above the stomach. It makes Bile a fluid made of lipids and salts. Bile dissolves fat in fatty foods. Next enzymes reach the fat molecules, and break them down. Bile is stored in the gall bladder.
Small Intestine
Small Intestine: Chemical digestion also takes place in the small intestine. Chyme is pushed through pyloric valve and enters the duodenum (the first of 3 parts). First chyme is mixed with fluids form the pancreases liver and lining of the duodenum. The chyme is now a rich mixture of medium and little nutrient molecules. The small intestine is adapted to absorb nutrients. The folds of the walls of the small intestine are covered in villi. Smooth muscles move the chyme down. Carbohydrates and protein are absorbed in the villi and lipids are absorbed in the lacteal.
Large Intestine
Large Intestine: When chyme is in the large intestine all the nutrients are gone. Now there is only water cellulose and indigestible material. The main job of the large intestine is to remove water. Water moves along the side of the walls of the large intestine. Rich colonies or bacteria thrive on indigestible material. They bacteria are very helpful they produce compounds that the body can use, such as vitamin K.
Rectum and Anus
Rectum: The wastes that remains after the water has been removed, goes out through the rectum. The rectum is a muscular ring at the end of the large intestine. It keeps the intestine closed until the pass of feces, and is a storage unit for the feces until they have been excreted.
Anus: Once the feces passes though the rectum it is excreted out of the external opining (anus.) Contractions of the sphincter muscles keep the anus closed.
Anus: Once the feces passes though the rectum it is excreted out of the external opining (anus.) Contractions of the sphincter muscles keep the anus closed.
