GI 1 Flashcards
What does the GI system do?
It acts as a portal for water and nutrient absorption, it aids in digest, has a well developed immune system, gives motility for digestion
What makes up the GI tract?
A continuous tube from mouth to anus made up of the pharynx, esophagus, stomach, duodenum, jejunum, ileu, colon
What are the relative sizes of the GI tract segments?
Pharynx, esophagus, and stomach = 65 cm
Duodenum = 25 cm
Jejunum and ileum = 260 cm
Colon = 110 cm
What is the route of food starting from the mouth?
Mouth and salivary glands –> pharynx –> esophagus –> LES –> stomach –> pyloric sphincter –> duodenum –> sphincter of Oddi –> Ileum –> Ileocecal valve –> colon –> rectum –> anal sphincter –> anus
What sources of digestion does the duodenum receive?
Pancreatic enzymes and bile from gall bladder (originally from liver)
What produces saliva?
Sublingual, parotid and submaxillary paired glands
What controls salivary production?
Secretion regulated by senses of thought, sight, smell, and chewing that act as promoters for the parasympathetic ANS
What is the signaling pathway for saliva release?
Promoters (senses) signal to higher center to fire on the salivatory nucleus of the medulla, which signal to Otic ganlion or submandibular ganglion that use Ach to signal parotid gland or submandibular galnd respectively to increase secretion
What is saliva release inhibited by?
Sleep, fatigue or fear
What is saliva made up of?
Mucins, amylase, water and has an alkaline pH
What does saliva do for us?
Helps with swallowing, initiates digestion, antibacterial, speech, and is a molecular solvent
Gastric secretion phases?
Cephalic phase (thought/smell of vagal interaction), gastric phase (HCl secretion stimulated by gastrin), intestinal phase (distension of stomach)
