enzyme A substance, usually a protein, that speeds up chemical reactions in the body.
esophagus The narrow tube that carries food from the throat to the stomach.
food allergies A condition in which the immune system reacts to harmless substances in
food as though they were harmful.
foodborne illness An illness caused by harmful bacteria that enter the digestive system
in food.
food intolerance Occurs when the digestive system is unable to break down a certain
type of food.
ileum The third part of the small intestine; covered with villi; the few remaining nutrients
are absorbed in the ileum.
jejunum The second part of the small intestine; where most nutrients are absorbed into
the blood; lined with tiny “fingers” called villi.
large intestine Therelativelywidetubebetweenthesmallintestineandanuswhereexcess
water is absorbed from food waste.
mechanical digestion Digestion in which large chunks of food are broken down into small
pieces.
peristalsis Involuntary muscle contractions which push food through the digestive system.
small intestine The narrow tube between the stomach and large intestine where most
chemical digestion and absorption of nutrients take place.
stomach The sac-like organ at the end of the esophagus where proteins are digested.
villi Containmicroscopicbloodvessels; nutrientsareabsorbedintothebloodthroughthese
tiny vessels; located on the jejunum and the ileum.
Points to Consider
- After nutrients are absorbed into the blood, think about how the blood could carry
them to all the cells of the body. How does the blood travel? What keeps the blood
moving?