Gastric Juice
Accounts for 30-50% of the gastric secretions
Cephalic phase
Where does protein digestion begin?
In the stomach because of pepsin
Protects the stomach lining from HCl
Mucus layer
Is made up of the products of mucous, chief, and parietal cells
Gastric juice
Digests lipids
Gastric lipase
Secreted by the chief cells
Gastric lipase
Accounts for 40-50% of the secretions
Gastric phase
In this phase, acid is secreted and it's inhibited when pH reaches 3.0
Gastric phase
A hormone that is secreted by cells near the parietal cells
Somatastatin
2. After pepsinogen is secreted, it then combines with HCl which is secreted from the ________cells
parietal
When the pH reaches ___ in the stomach, the acid stops secreting
1.5
A high pH of __ or more indicates the need for acid
4
Secreted by the mucus cells
A thin mucus layer
A neurotransmitter
Acetylcholine
It's secreted in response to the parasympathetic nervous system in normal conditions
Acetylcholine
Stimulates cells in the pylorus to secrete the hormone gastrin
Acetylcholine
Suppresses somatastatin and allows HCl to be secreted when needed
Acetylcholine
Begins before food reaches the stomach
Cephalic phase
Controlled by the parasympathetic nervous system
Cephalic phase
Controls the psychological influences such as the smelling, thinking or first taste of food
Cephalic phase
3 phases of gastric juice secretion
Cephalic phase, gastric phase, and intestinal phase
1. Secretes pepsinogen
Chief cells
A hormone secreted by the small intestines, and targets the stomach, but inhibits gastric movement
Cholestokinin
CKK
Cholestokinin
When the stomach stretches due to the presence of food which stimulates gastric secretions
Gastric phase
Stimulates gastric juice release
Gastrin
A hormone secreted by the small intestines, but it targets the stomach
Intestinal gastrin
Enhances gastric gland secretions
Intestinal gastrin
3 hormones are secreted in the intestinal phase; they secrete in order, not at the same time
Intestinal gastrin, cholestokinin, and intestinal somatostatin
Accounts for about 5-10% of the secretions
Intestinal phase
Begins when food enters the small intestines
Intestinal phase
A hormone secreted by the small intestines, targets the stomach, but inhibits all gastric juice secretions
Intestinal somatostatin
Helps absorb vitamin B12 into the blood
Intrinsic factor
Is secreted by parietal cells
Intrinsic factor
3. Pepsinogen + HCl =
Pepsin
Breaks down protein
Pepsin
Inhibits
Slows down
Always inhibits something
Somatastatin
Inhibits the secretion of HCl
Somatastatin
