• Digestion is the process that breaks down food
into smaller molecules so they can be absorbed
and moved into the blood for use in the body’s
• Digestion is both mechanical and chemical
• Mechanical digestion takes place when food is
chewed, mixed, and churned – the physical
breakdown of food.
• Chemical digestion occurs when chemical
reactions break down food molecules
• Chemical digestion is possible because of enzymes
• An enzyme is a type of protein that speeds up the
rate of chemical reaction in your body
• Peristalsis refers to the wave of muscle
contractions that move food through the digestive
• Digestion starts in the mouth, which includes the
tongue, teeth and salivary glands
• The esophagus is a muscular tube that connects the
throat to the stomach.
– A structure called the epiglottis covers the
opening to the windpipe to prevent choking
• The stomach is a muscular “bag” where a major
part of digestion occurs.
• Food moves through the stomach in 2 to 4 hours
and is changed into a liquid consisting of gastric
juices and partly digested food.
* This liquid is called chyme.
• The small intestine runs between the stomach
and the large intestine.
• As chyme leaves the stomach, it enters the
duodenum, the first part of the small intestine
• The pancreas is a large gland behind the stomach
that secretes enzymes into the duodenum.
• The pancreas also produces insulin, a hormone
that regulates the amount of sugar in the blood
• The large intestine absorbs water from the
undigested mass of chyme. After excess water is
absorbed, the remaining materials become more
solid. The large intestine is also called the colon.
• The last parts of the large intestine are the
rectum and the anus. These organs control the
release of solid waste from the body.