Esophagus Flashcards
esophagus
a hollow, muscular tube that connects the pharynx to the stomach
transport food (bolus) from the mouth to the stomach
why does the esophagus produce mucus
keep the passage moist and make it easier for the bolus to move
Peristalsis
series of muscle contractions
starts in the esophagus and continues through the rest of the digestive tract
Sphincters
muscles that are found along the digestive tract
open & close to allow materials to pass through
what happens when sphincters are relaxed
esophagus is open and food will go into the stomach
when they are contracted, the esophagus is closed
normally closed to prevent the acidic contents of stomach from going into the esophagus
stomach
Temporarily stores food while both mechanical & chemical digestion takes place
structure of stomach
has thick walls - Elastic and very muscular
can stretch to hold more food
Gastric Juice
Performs chemical digestion; unique to the stomach
Millions of gastric glands produce gastric juice, stimulated by food.
what is in gastric juice
contains hydrochloric acid, salts, enzymes, water, and mucus; highly acidic (more acidic than battery acid)
how is the stomach protected from gastric juice
Stomach lining secretes mucus to protect it from strong acid
how does gastric juice help digest food
Three layers of muscle fibers churn food, breaking it mechanically and mixing it with gastric juice
Nerves around the stomach regulate activities and start contractions to release partially digested food
Chyme
name for food once it leaves stomach
peristaltic wave become strong when chyme is ready to leave stomach -forces chyme out
where is chyme stored
when the small intestine is full and still digesting food, the stomach temporarily stores chyme
Pyloric Sphincter
muscular valve at the lower end of the stomach
closed - food stays in the stomach
opened - food goes into the small intestine
where does the pyloric sphincter move chyme
out of the small intestine into the large intestine then chyme is pushed into duodenum
