Digestive System 2 Flashcards
Where is the stomach located and shape?
J-shaped left superior side of abdomen, hollow and elastic
What does the elasticity of stomach allow?
Increase in diameter and volume of stomach
What are the functions of the stomach?
Store food, continue digesting carbs, initiate fats, and proteins digestion
Where does the majority of chemical and mechanical digestion occur?
Stomach
What happens during stomach peristalsis?
The chyme is pushed towards the pyloric sphincter in waves which then are retropulsed towards the stomach, breaking down the food into tiny particles suitable for the small intestine
How does food enter stomach?
Cardiac/lower esophageal sphincter
What is the pyloric sphincter?
valve which leads chyme into small intestine
What are the 4 regions of the stomach?
Cardia, fundus - storage, body and pylorus which regulates the emptying of chyme into small intestine
What is the mucosa layer of the stomach?
Simple cuboidal layer surface mucous cell layer to protect the lining of the stomach, which is filled with acidic and gastric juices, lamina propria (areolar connective tissue) and muscularis mucosae (smooth muscle)
What 4 cell types do gastric glands contain?
Mucous neck, parietal, chief & G cells
What are gastric glands?
epithelium columns of mucus cells that extend into the lamina propria and at bottom are gastric pits
What do parietal cells secrete?
Intrinsic factor & HCL
What do chief cell secrete?
Digestive enzymes (lipase, pepsin)
What do G cells secrete?
Hormones such as gastrin
What is special of the gastric muscularis membrane?
Muscularis is made of three layers; oblique (diagonal), circular, and longitudinal (bottom) which help with stomach contractions.
What are the 7 gastric secretions?
HCL, pepsinogen, renin, lipase, intrinsic factor, hormones & mucus
What are the functions of HCL?
Kill bacteria & parasites, activate pepsin & lingual lipase secretion, digest plant products & cell walls, break protein bonds, change bolus into chyme, convert ferrous ions into ferric ions
What are the functions of pepsinogen?
Is the inactive form of pepsin, activated by HCL which breaks it into polypeptides and peptides and removes peptides to form pepsin which digests proteins
What are the functions of lipase?
Digestive enzyme that breaks fats into glycerol and fatty acids
What are the functions of renin?
Only found in the gastric glands of babies and curdle milk, and slow digestion of proteins to maximize nutrition
What are the function of Intrinsic Factor?
Needed for the absorption of B12 in small intestine
What is the function of mucus in stomach?
Protect gastric lining from acids, abrasions and enzymes
What are the hormones & their functions?
Gastrin & histamine regulate HCL, serotonin & somatostatin regulate stomach motility
What are the 3 regions of the small intestine?
Duodenum, jejunum & ileum from shortest to longest