The gastric mucosal barrier protects the stomach from acid damage and is composed of a tight epithelial cell lining, a mucus coating, and bicarbonate ions. Mucus secreted by mucus cells throughout the GI tract acts as a protectant and lubricant. It maintains the alkaline pH of epithelial cells despite gastric acid through its buffering properties. Peptic ulcers occur when this barrier is damaged, such as through excess acid secretion, bacterial infection by Helicobacter pylori, or drug use like NSAIDs. Common symptoms include upper abdominal pain relieved by food or antacids.
This document discusses toxicity from pesticides, specifically organophosphates and paraquat. It provides information on:
1) Organophosphates are commonly found in household and agricultural pesticides as well as some medical treatments. They work by inhibiting cholinesterase enzymes, leading to excess acetylcholine and symptoms like muscle fasciculations, weakness, and seizures.
2) Paraquat is a herbicide that is toxic when ingested, with a lethal dose between 1-4 grams. It causes lung damage through redox cycling and production of reactive oxygen species.
3) Clinical manifestations of organophosphate toxicity include muscarinic effects like increased salivation as well as nicotinic effects
This document summarizes drugs acting on the GI system. It discusses antiemetics which prevent nausea and vomiting like ondansetron, domperidone, and cyclizine. Emetics like ipecac and apomorphine induce vomiting. Laxatives like lactulose, bisacodyl, and docusate are used to treat constipation. Antacids like aluminum hydroxide and magnesium hydroxide neutralize stomach acid. Proton pump inhibitors like omeprazole and pantoprazole inhibit acid secretion. Antidiarrheals like loperamide and diphenoxylate decrease intestinal motility. Histamine receptor blockers like cimetidone and ranitidine inhibit
The gastrointestinal endocrine system regulates digestion through hormone secretion. It contains endocrine cells that secrete hormones like gastrin, cholecystokinin, and ghrelin to regulate processes like nutrient absorption, gut motility, and blood flow. These hormones are released in response to factors like food intake, pH levels, and distension. They target organs like the stomach, pancreas, gallbladder and hypothalamus to coordinate the digestive response. The gastrointestinal endocrine system plays an important regulatory role in fish as well through hormones that influence growth, metabolism, food intake and endocrine balance.
The gastrointestinal tract produces over 25 hormones that help regulate digestive secretions and motility. Key hormones include gastrin, released by stomach cells in response to food, which stimulates gastric acid secretion; cholecystokinin, released by the duodenum in response to fats and acids, which stimulates gallbladder contraction and pancreatic enzyme release; and secretin, released by the duodenum in response to stomach acid, which stimulates pancreatic bicarbonate secretion to neutralize acid. Other important hormones are motilin, which controls gastrointestinal motility, and peptide YY and neurotensin, which are involved in regulating pancreatic and gastric secretions and gastrointestinal motility. Hormone-secreting
The gastric mucosal barrier protects the stomach from acid damage and is composed of a tight epithelial cell lining, a mucus coating, and bicarbonate ions. Mucus secreted by mucus cells throughout the GI tract acts as a protectant and lubricant. It maintains the alkaline pH of epithelial cells despite gastric acid through its buffering properties. Peptic ulcers occur when this barrier is damaged, such as through excess acid secretion, bacterial infection by Helicobacter pylori, or drug use like NSAIDs. Common symptoms include upper abdominal pain relieved by food or antacids.
This document discusses toxicity from pesticides, specifically organophosphates and paraquat. It provides information on:
1) Organophosphates are commonly found in household and agricultural pesticides as well as some medical treatments. They work by inhibiting cholinesterase enzymes, leading to excess acetylcholine and symptoms like muscle fasciculations, weakness, and seizures.
2) Paraquat is a herbicide that is toxic when ingested, with a lethal dose between 1-4 grams. It causes lung damage through redox cycling and production of reactive oxygen species.
3) Clinical manifestations of organophosphate toxicity include muscarinic effects like increased salivation as well as nicotinic effects
This document summarizes drugs acting on the GI system. It discusses antiemetics which prevent nausea and vomiting like ondansetron, domperidone, and cyclizine. Emetics like ipecac and apomorphine induce vomiting. Laxatives like lactulose, bisacodyl, and docusate are used to treat constipation. Antacids like aluminum hydroxide and magnesium hydroxide neutralize stomach acid. Proton pump inhibitors like omeprazole and pantoprazole inhibit acid secretion. Antidiarrheals like loperamide and diphenoxylate decrease intestinal motility. Histamine receptor blockers like cimetidone and ranitidine inhibit
The gastrointestinal endocrine system regulates digestion through hormone secretion. It contains endocrine cells that secrete hormones like gastrin, cholecystokinin, and ghrelin to regulate processes like nutrient absorption, gut motility, and blood flow. These hormones are released in response to factors like food intake, pH levels, and distension. They target organs like the stomach, pancreas, gallbladder and hypothalamus to coordinate the digestive response. The gastrointestinal endocrine system plays an important regulatory role in fish as well through hormones that influence growth, metabolism, food intake and endocrine balance.
The gastrointestinal tract produces over 25 hormones that help regulate digestive secretions and motility. Key hormones include gastrin, released by stomach cells in response to food, which stimulates gastric acid secretion; cholecystokinin, released by the duodenum in response to fats and acids, which stimulates gallbladder contraction and pancreatic enzyme release; and secretin, released by the duodenum in response to stomach acid, which stimulates pancreatic bicarbonate secretion to neutralize acid. Other important hormones are motilin, which controls gastrointestinal motility, and peptide YY and neurotensin, which are involved in regulating pancreatic and gastric secretions and gastrointestinal motility. Hormone-secreting