Digestive System

• Food passes through a long tube inside the body know as the alimentary canal or gastrointestinal tract (GI)
• The mouth is where food enters the digestive system
• Teeth are used to break down food into smaller pieces so that it can be swallowed more easily.
• Saliva contains enzymes which start breaking down carbohydrates, fats and proteins.
• Saliva contains enzymes which start breaking down carbohydrates, making them easier to digest.
• Tongue helps move food around your mouth, mixes with saliva and pushes food towards the throat.
• There are two types of digestion: Mechanical and Chemical
• Mechanical digestion involves physical processes such as chewing, grinding and mixing.
• Chemical digestion involves chemical reactions between enzymes and food molecules.
• In Mechanical digestion, the food is broken down into smaller particles. This usually happens in the mouth through the action of the teeth and tounge
• Chemical digestion. This is the process where complex molecules like proteins, fats, ,and carbohydrates are broken down into nutrients and other substances that your body can use. It requires special proteins called enzymes.
• The digestion begins in the mouth where food is mechanically digested
• There are 4 types of teeth. These are incisors, canines, premolars and molars.
• The incisors have thin edges and are used for cutting food.
• The canines are pointed and are for tearing food, particularly meat
• The broader and bigger premolars and molars are for crushing and grinding food
• The chewed food is now called bolus
• Bolus passes through the pharynx and then to the esophagus
• The smooth muscles of the esophagus contract in a rhythmic and wavelike motion called peristalsis. It pushes the bolus down to the stomach
• The stomach is a large, pear-shaped organ that can temporarily expand to store food.
• As the bolus enters the organ, the sphincter muscles at the ends of the stomach contract to keep it in
• When bolus is mixed with acid, it changes consistency. It is now called chyme. It is then pushed into the small intestine
• The small intestine is a long coiled tube where most of the digestion takes place
• Accessory Digestive Organs: Liver, Pancreas, Gallbladder
• The liver is the largest organ in the body and is located near the stomach
• The liver produces bile that helps break down fats
• The gallbladder is a small sac under the liver where the bile is stored
• During the digestion, the gallbladder release bile into the small intestine
• The pancreas is an elongated organ behind the stomach. It secretes substances that help break down protein and fats in the small intestine
• The pancreas produces insulin which regulates the amount of sugar in the blood
• In the large intestine, water is absorbed and the remaining undigested food is broken down until only the parts not useful to the body are left
• The waste will be expelled from the body in the form of feces.
• The last sections of the alimentary canal are the rectum and anus
• The rectum provides a temporary storage for feces before they are excreted
• Peristalsis of the smooth muscles in the rectum pushes the feces out of the body through the anus