AP BIOLOGY

Detailed explanation-1: -Esophagus: The esophagus is a muscular tube that connects the pharynx (throat) to the stomach. The esophagus contracts as it moves food into the stomach. A “valve” called the lower esophageal sphincter (LES) is located just before the opening to the stomach.

Detailed explanation-2: -Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract.

Detailed explanation-3: -At the end of the esophagus, a muscular ring or valve called a sphincter (pronounced: SFINK-ter) allows food to enter the stomach and then squeezes shut to keep food or fluid from flowing back up into the esophagus.

Detailed explanation-4: -STOMACH. The stomach stores swallowed food and liquid, mixes the food and liquid with digestive juice it produces, and slowly empties its contents, called chyme, into the small intestine. The muscle of the upper part of the stomach relaxes to accept large volumes of swallowed material from the esophagus.

Detailed explanation-5: -The esophagus: Food travels down a muscular tube in the chest called the esophagus (ih-SAH-fuh-gus). Waves of muscle contractions called peristalsis (per-uh-STALL-sus) force food down through the esophagus to the stomach. A person usually isn’t aware of the muscle movements that push food through the digestive tract.