Chapter 17: Digestive System Flashcards
two types of secretory glands in salivary glands
- serous
- mucus
serous
produce a watery fluid, containing a digestive enzyme called salivary amylase
mucus
secrete mucus
bolus
food chewed & mixed with mucus
pharynx
cavity posterior to mouth; extends from nasal cavity to esophagus and connects nasal to oral cavity
parts of the pharynx
- oropharynx
- nasopharynx
- laryngopharynx
esophagus
tubular organ that extends from pharynx to stomach, contains mucus glands in submucosa
lower esophageal sphincter
regulates food passage into stomach
esophageal hiatus
hole where esophagus connects to stomach
stomach
j-shaped, rugae, receives food, mixes w/ gastric juice, initiates protein digestion, limited absorption, moves food into small intestine
smooth muscle layers of stomach:
- inner circular
- outer longitudinal
- some areas have a third oblique layer
how many glands do gastric glands contain?
3 secretory cells, which produce gastric juice
gastric juice components (6)
- pepsin
- pepsinogen
- HCl
- gastric lipase
- mucus
- intrinsic factor
pepsinogen
inactive form of pepsin; secreted by chief cells
pepsin
active enzyme that breaks down proteins into polypeptides; requires presence of HCl
gastric lipase
fat splitting enzyme, found in small quantities; action inhibited by low pH
HCl
produced by parietal cells; converts pepsinogen to pepsin
intrinsic factor
produced by parietal cells; required for B12 absorption
what things does the stomach break down?
alcohol, drugs
stomach’s main job
break down food
neural regulation
- sympathetic impulses decrease gastric activity
- parasympathetic impulses increase gastric activity; promote release of histamine, which stimulates gastric secretion
somatostatin
inhibits HCl secretion
gastrin
increases gastric juice secretion
cholecystokinin (CCK)
decreases gastric motility
