Lumen of stomach
Oblique layer of muscle
Circular layer of muscle
layer of muscle
Three-dimensional view of layers of the stomach
Surface mucous cell
Mucous neck cell
acid and intrinsic factor)
Chief cell (secretes
G cell (secretes
the hormone gastrin)
forms a protective barrier between the
mucosa and the gastric secretions in the
Hydrochloric acid creates
gastric pH of 2.0
kills microbes and activates pepsinogen into pepsin
is essential for absorption of vitamin B12.
is an inactive gastric enzyme that becomes
pepsin (the active enzyme).
breaks down fats.
enters the bloodstream and stimulates secretion
of gastric juice, motility of GI tract, and relaxation of
Sectional view of the stomach mucosa showing gastric glands and cell types
To summarize, the main functions of the stomach in-
clude the following:
Mixes saliva, food, and gastric juice to form chyme.
Serves as a reservoir for food before release into the
Secretes gastric juice, which contains HCl (kills bacteria
and denatures protein), pepsin (begins the digestion of
proteins), intrinsic factor (aids absorption of vitamin
B12), and gastric lipase (aids digestion of triglycerides).
Secretes gastrin into blood.
Let's Journey Through the Digestive System 407