Upper GI Tract Flashcards
What is digestion
Breaking down macromolecules to allow absorption
What is absorption
Moving of nutrients and water across a membrane
Basic plan of gut wall
Mucosa: epithelium, lamina propria (loose connective tissue), muscularis mucosae
Submucosa: connective tissue (containing nerve plexus)
Muscularis: smooth muscle (containing nerve plexus)
Serosa/Adventitia: connective tissue +/- epithelium
How many teeth do we have in an permanent set
32
What are the muscles that aid chewing
Masseter muscle - largest jaw muscle responsible for biting
Several muscles control position of mandible
What are the enzyme secreted in oral cavity
Food mixed with saliva
Lingual lipase
Salivary amylase
What do the muscles of the tongue do
Intrinsic muscles - fine motor control and moving food
Extrinsic muscles - gross movement of tongue (in, out, up and down), assists mechanical digestion
How is the oesophagus epithelium like
Non keratinising squamous epithelium
Wear and tear linign (extremes of temp and texture)
Lubrication - mucus
Muscles of the oesophagus
Circular - allow food to remain in oesophagus
Longitudinal - propagates food bolus
What happens to cells when acid reflux go into oesophagus
Squamous to columnar
What is the significance of the gastro oesophageal junction
Reflux prevented by diaphgram
Epithelial transition
Gastric folds - rugae
What happens during upper oesophageal phase
Upper sphincter closes
Superior circular muscle contract and inferior rings dilate
Sequential contraction of longitudinal muscle
What happens during lower oesphageal phase
Lower sphincter closes as food passes trhough
What does the stomach do
Breaks down food into smaller particles
Holds food, releasing it in a controlled steady rate into duodenum
Kills parasites and certain bacteria
Which part of the stomach secretes what
Cardia and pyloric region - mucus only
Body and fundus - mucus, hcl, pepsinogen
Antrum - gastrin
What does the stomach contain
Mucins - gel coating to prevent epithelium from eroding
HCO3- trapped in mucus gel
pH = 1-2
Stomach movements
Peristalsis - 20% stomach contractions - propels chyme towards colon -ANS ESSENTIAL
Segmentation - 80% stomach contractions, weaker, fluid chyme towards pyloric sphincter, solid chyme pushed back to body - ENTERIC NS
Stomach - chief cell
Protein secreting epithelial cell
About RER and golgi for packing and modifying
Secretes pepsinogen
Apical secretion granules
What is the parietal cell resting
What happens when parietal cell is secreting
Tubulovesicles fuse with membrane
Microbilli proejct into canaliculi
How does HCl get into the stomach
K moves into the lumen
Cl moves into the lumen
H/K atpase pump
Picture of H/K ATPase pump and carbonic anhydrase pump
What is gastrin
Stimulate histamine release from chromaffin cells
What is the cephalic phase of gastric secretion
What is the gastric phase of
What is the intestinal pahse of gastric secreiton
Inhibition of pepsinogen and gastric acid
How migh you produce a useful drug to decrease acid secreiton
What stimul iwill decrease acid secretion in teh stomach
Chyme fatty acid content
Protein content of the meal
