GI 1 Flashcards
(56 cards)
What type of cells lubricate, protect and digest?
epithelial
How many liters of water does the GI tract absorb each day?
9-10 L
Stomach acid is what pH? what is it in the jejunum?
1 and 7
What is the function of there large intestine?
absorption of water and electrolytes, host defense, dehydration and compaction of materials for elimination
Where do organic substances and victims, host defense occur?
small intestines
What section of the GI tract does not have a smooth muscle layer?
Esophagus
What are the 4 layers of the GI tract?
inside out: mucosa, submucusa, intramural plexus, muscularis, serosa “my sub in moscow sucks”
What layer are the glands and vessels located?
submucosa- secretion! (also has blood vessels)
What are the layers of the serosa?
connective tissue layer and the peritoneum
Layers of the Mucosa?
mucous epithelium, lamina propria, muscularis mucosae (lymph nodes)
Muscularis?
Circular layer,longitudinal layer and the stomach has an oblique layer
The mesentery is what? and it contains what?
it is the outer layer of the GI tract and contains the blood vessels, nerves and extends into the serosa and muscularis
Celiac, superior mesenteric artery, inferior mesenteric artery drain into where?
Portal vein
What are the three muscular layers of the stomach
longitudinal, circular, oblique
What are the layers of the GI tract at the cellular level
MUCOSA LAYER: Mucous neck cells, parietal cells, chief cells, endocrine cells, progenitor cells
What do parietal cells secrete?
HCL and IF
What do Chief cells secrete?
Pepsinogen and gastric lipase
Regulation of the GI tract 6 components:
- Enteric nervous system (myenteric plexus, submucosal plexus for secretions)
- Parasympathetic plexus (mainly vagal to transverse colon and nerves to anus)
- Sympathetic nervous systems (post ganglionic andrenergic fibers from celiac, super and inf. mesenteric and hypogastric plexus)
- Central nervous system
- Lumenal chemo-, mechano-, and osmoreceptors (act on enteric NS)
- Hormones
Starch gets broken down down in the mouth via what and to what?
salivary amylase breaks starch down to oligosaccharides and dextrins
What happens to starches in the small intestines?
Oligosaccharides get broken down by pancreatic amylase to lactose, maltose, sucrose.
What are the brush border enzymes for starch?
lactase, maltase, sucrase, they break down the galactose, glucose, fructose.
Lactase, Maltase and Sucrase do?
Lactase: lactose to galactose and glucose
Maltase: maltose to glucose and glucose
Sucrase: sucrose to glucose and fructose
At what level of carbs breakdown can the villa of the small intestine start absorbing?
monosaccharides: galactose, fructose, glucose
Where does protein digestion start?
in the STOMACH with pepsin in the presence of hydrochloric acid. Proteins break down to peptones and proteases