Cells that line the stomach secrete a gel like mucus that is insoluble which

Cells that line the stomach secrete a gel like mucus

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- Cells that line the stomach secrete a gel like mucus that is insoluble which has bicarbonate dissolved in it which stops the stomach from auto-digesting itself  h.pylori lives here and metabolizes urea by secreting ureases and degrades it to NH4+ which can cause ulcerations because your buffering capacity is reduced. H. pylori also release phospholipase that degrade phospholipid - invaginations of epithelium form gastric pits - gastric pits merge with gastric glands in the lamina propria and stop at the muscularis mucosae gastric gland made of isthmus (continuation of pith (opening) + neck (contains mucus nexx cells secrete mucus that becomes part of chyme) +base (contain parietal and chief cells, and G cells) Found in the fundic/body:  parietal cells - secrete precursor (H+ via H+ pump) which turns into HCL H+ is created via carbonic acid buffer system because parietal cells contain CA. CO3 – is dumped into blood via a chloride bicarbonate exchanger and H+ is dumped into the lumen of the stomach via proton atp-ase Alkaline tide – when your blood is a little more basic due to the CO3- being released into the blood  chief cells – secrete pepsinogen into the stomach. When HCl is released pepsinogen (is a pepdidase that can auto cleave itself) becomes pepsin - also release gastric lipase which degrade lipids into 3 fatty acids and glycerol (works optimal at pH 5) but no bile so lipid is not digested properly - Also secretes rennin that coagulates milk protein (casein). Only in infants. This way transit time is reduced and it is more exposed to pepsin - Found in the pyloric region  G cells (gastroendocrine cells) – secrete gastrin  D cells – secrete somatostatin (released when you are not eating tonically because of high acidity – low pH - proton)
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 Gr cells – release graylin during the fasting state and stimulates the brain (hypothalamus) to tell you, you’re hungry adipose – release leptin which causes satiety by going to the hypothalamus and inhibiting appetite - in fat people, leptin levels are so high which is weird because you wouldn’t think they would have that but they do and their hypothamalus Is desensitized to the leptin - stomach has 3 layers for muscle - rugae – folds in the stomach composed of mucusa and submucusa found when the stomach is empty - h. pylori lives in gastro mucosal barrier and secretes ureaeses and phospholipases which reduce buffering capacity - gastro mucosal barrier (pH 7) can be restored by drinking milk because milk contains phospholipids Pyloric Glands - mucous secretion - contain gastroendocrine cells that secrete endocrine hormones - G cells secrete gastrin; stimulates gastric secretions and activity by parietal cells  gastrin upregulates the activity of the stomach - D cells secrete somatostatin in a fasting state because of high acidity levels; inhibits gastrin release - releases graylin which increases appetite Regulation of Gastric Activity - acid and enzyme production is controlled by the central nervous system and regulated by the enteric nervous system and hormones - three phases of control: cephalic, gastric and intestinal
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