10.6 The Gastrointestinal Tract Flashcards
What are the three main roles of the mouth in digestion of food?
- fragmentation
- lubrication
- enzyme digestion
How is fragmentation by the mouth accomplished?
mastication
What is saliva?
viscous fluid secreted by the salivary glands that contains salivary amylase
What does salivary amylase do?
hydrolyzes starch to disaccharides
Where is lingual lipase found and what is its function?
saliva; fat digestion
What is a bolus and where is it formed?
smooth lump that can be easily swallowed; formed in the mouth
What is the pharynx?
throat
What is the uvula?
floppy thing that hands at the back of the throat
What are the two openings that the pharynx contains?
trachea and esophagus
What is the trachea?
cartilage lined tube at the front of the neck which conveys air to and from the lungs
What excludes solids and liquids from entering the trachea during swallowing?
epiglottis
What is the esophagus?
tube that uses peristalsis to convey bolus to the stomach
What are the two muscular rings in the esophagus and what are their functions?
upper esophageal sphincter
lower esophageal sphincter (cardiac sphincter); control movement of food through esophagus
What are the three main purposes of the stomach?
- partial digestion of food
- regulated release of food into the small intestine
- destruction of microorganisms
What is the pH of the stomach and what causes it?
2; secretion of HCl by parietal cells located in the gastric mucosa
