Lecture 4 Flashcards
The stomach
Hollow, muscular organ that continues chemical and mechanical digestion
Regions of stomach:
Cardia, fundus, body, antrum, pylorus
Pylorus divided into
antrum and canal
Pyloric sphincter regulates
movement into small intestine
Rugae
allow expansion of stomach
Muscularis contains
additional oblique layer
Mucosa contains
gastric pits
Gastric glands secrete
gastric juice
Parietal cells secrete
hydrochloric acid and intrinsic factor
Chief cells secrete
pepsinogen
Mucous neck cells secrete
mucus
Enteroendocrine cells
—secrete hormones
Different phases of Gastric secretion
Cephalic phase
Gastric phase
Intestinal phase
Cephalic phase
—begins when body is alerted by the smell, taste, sight, or thought of food
Gastric phase
—activated by nervous and endocrine system when food enters stomach
Results in increased gastric secretion & motility
Intestinal phase
Excitatory—duodenum increases gastric secretion
Inhibitory enterogastric reflex inhibits gastric secretion & movement when small intestine is full
alpha salivary amylase lies in the fundus of the stomach - it is denatured due to the low pH levels - thus, it is inactive in the fundus
What mixes and churns food?
Body of the stomach
Pepsinogen
The inactive form of pepsin (which breaks down proteins)
- it becomes active after secretion of HCL
- mucous of stomach = protective layer against pepsin
Tight junctions
- prevents contents from leaking out and going where not supposed to
- also for cell to cell communication
