GI Overview Flashcards
What happens when you first smell food?
Salivary glands release:
- Serous/Mucous fluid -> HCO3
- Amylase
- Lipase
Churning of stomach
Activation of pancreas and Gall bladder by extrinsic nervous system
What is the pathology of Sjogren’s syndrome?
- Autoimmune destruction of tissues —> Accumulation of ECM In Salivary glands
- Low levels of HCO3- —> Acidic contents —> Tissue injury/pain
- Dry mouth and dry eyes
What happens to food in the stomach?
- Food storage
- Mixing of food
- Release of Acid/Lowering of pH
- Cells release Pepsinogen —> Pepsin; an enzyme which cleaves proteins
Describe how Cystic fibrosis affects pancreas function?
- Pancreas stimulates lipase
- CF pancreas is damaged —> No production of lipase —> Fat malabsorption
Differentiate functions of liver and gallbladder.
Liver:
- Make bile
- Recieves nutrients
- Makes blood proteins
- Detoxifier
Gallbladder: Stores and concentrates bile
What occurs in the post pyramidal period?
Blood is diverted from skeletal muscles to intestines increasing blood blow up to 5X
What are the Neurocrines of the GI system?
VIP, GRP, Enkephalins
What is VIP and it’s function?
Vasoactive intestinal polypeptide:
- Homologue to secretin
- Produces relaxation of GI smooth muscle including lower esophageal sphincter
- Stimulates pancreatic HCO3- secretion and inhibits gastric H+ secretion
***VIPomz —> Watery diarrhea, Hypokalemia, and achlorhydria
What are the paradise mechanisms of the GI system?
Gastrin + Vagus Nerve —>Histamine —> INC H+ by parietal cells
INC Luminal H+ and D cells of GI system —> Somatostatin —> DEC Gastrin and histamine release ad therefore DEC H+ secretion
What is GIP and what are it’s triggers and actions? What cells secrete it?
Glucose-dependent insulinotropic peptide:
- Secreted by K Cells of duodenum
- Stimulated by Fats, FAs, Proteins, Carbohydrates, glucose
- Decreases H+ secretion, motility, and emptying
- Increases Insulin secretion
- Stimulates Insulin secretion
***At large does, inhibits gastric secretion and motility
Describe Gastrin:
- Release
- Action
- Inhibition
- Released vey parietal cells
- INC H+ and stimulates growth of gastric mucosa
- Stimulated by Stomach distention, vagus nerve via GRP, and Phe/Try
- Inhibited by H+ in lumen of stomach, somatostatin
- inhibited by Zollinger-Ellison syndrome
*Gastrin is inactive in kidney and SI
Describe Zollinger Ellison Syndrome
- Gastrinoma
- Uncontrolled increase in Gastrin Secretion which upregulates gastric secretions
- Parietal Cell Hyperplasia in body
- Gastric ulcers in unusual locations such as esophagus and Jejunum
Describe Secretin:
- Release
- Function
- Inhibition
- Homologue to glucagon
- Stimulates HCO3- Secretion and exocrine pancreas
- Increase bile production
- Inhibits H+ release by parietal cells
- Stimulated by S Cells of Duodenum from too much H+ or Fatty Acids
Describe CCK:
- Secretion
- Functions
- Inhibition
- stimulation
- Homologue to Gastrin
- I Cell of Duodenum
- Contracts gallbladder, relaxes sphincter of Oddi, stimulates pancreas, Stimulates secretin
- Inhibits Gastric emptying via contracting pyloric sphincter
- Stimulated by small peptides and amino acids (NOT triglycerides)
What is the only hormone which responds to Fat, protein, and carbohydrates?
GIP
