Lesson 2- From the mouth to the stomach Flashcards
Chemical digestion
The breakdown of food molecules into simpler components (monomer) by digestive enzymes; each chemical reaction is catalyzed by a specific enzyme protein
Digestive tract
A tube composed of all the organs that carry food and/ or waste materials on the journey from the mouth to the anus
Gastric juice
A strong acidic liquid created in the stomach; pH 1 to 3 in humans, which is close to being colourless
Hydrochloric acid (HCI)
A strong acid produced in the cells of the stomach; makes the stomach contents very acidic (pH=2); kills bacteria; activates the enzyme pepsinogen to form pepsin (pepsin is responsible for the first step in protein digestion)
Mechanical (physical) digestion
The mechanical processes that break down food into smaller particles; the main sites of mechanical digestion are the mouth and stomach; increasing the surface area of food particles and the effectiveness of enzymes that chemically digest food molecules
Mucus
A substance secreted by mucous cells in the digestive tract; protects the lining of the digestive tract from its own digestive juices; particularly important for preventing ulcers from forming on the stomach lining
Pepsin
A digestive enzyme released by the chief cells in the stomach that functions to degrade food proteins into peptides
Pepsinogen
A protein found in gastric juices; activated by HCI to from pepsin, which catalyzes the chemical digestion of proteins into peptides
Peristalsis
Involuntary contractions of muscles, primarily in the digestive tract, that occur in progressive wavelike contractions
Salivary amylase
An enzyme protein responsible for the chemical digestion of starch, which is converted to maltose
Swallowing
A reflex action that happens automatically, pushing the bolus into the esophagus
