GI Absorption
- Stomach
- Alcohol
- Duodenum
- Iron
- Jejunum
- Folate
- Terminal Ileum
- Vitamin B12
- Bile Resorption
Oral Cavity
- Mouth
- Mechanical Digestion
- Salivary Amylase Begins Carbohydrate Breakdown
- Lingual Lipase Begins Lipid Breakdown
- Esophagus
- Bolus
- Peristalsis
Stomach Digestion
- Chief Cells Secrete Pepsinogen
- Pepsinogen Turned to Pepsin By H+
- Protein Breakdown Begins
- Mucous Cells Secrete Mucus and Bicarbonate
- G Cells Secrete Gastrin
- Gastrin Stimulates Parietal Cell HCl Release
- Parietal Cells Secrete Intrinsic Factor
Small Intestine Absorption
- Carbohydrates Undergo Active Transport
- Amino Acids Undergo Active Transport
- Small Lipids Undergo Passive Diffusion
- Epithelial Cells
- Intestinal Capillaries
- Hepatic Portal Transports Nutrients
- Liver
- Large Lipids Transported as Chylomicrons
- Lacteals Transport Chylomicrons
Small Intestine Digestion
- Brush border enzymes
- Pancreatic Enzymes are secreted via a Duct
- Pancreas secretes bicarbonate
- Brush Border activates Pancreatic Trypsin
- Trypsin activates Chymotrypsin
- Trypsin and Chymotrypsin digest Proteins
- Gallbladder Releases Bile
- Pancreatic Lipase breaks down Lipids
- Goblet cells secrete mucus
- Pancreatic Amylase breaks down Carbohydrates
- Pancreatic Nucleases breakdown DNA/RNA
- Digestion occurs in the Duodenum
Large Intestine
- Colon
- Electrolyte Reabsorption
- Water Reabsorption
- Microflora Produce Vitamins
- Rectum Stores Feces
Cholecystokinin (CCK)
- Secreted by I Cells
- Duodenum and Jejunum
- Increase Pancreatic Secretions
- Increase Gallbladder Contraction
- Induce Relaxation of Sphincter of Oddi
- Decrease Gastric Emptying
- Increased by Fatty Acids and Amino Acids
Somatostatin
- Secreted by D Cells
- Pancreas
- GI Tract
- Decrease Secretion of Gastric Acid and Pepsinogen
- Decrease Pancreatic and Small Intestine Fluid Secretion
- Decrease Gallbladder Contraction
- Decrease Glucagon and Insulin Secretion
- Secretion is Increased by Acid
- Secretion is Decreased by Vagal Stimulation
- Octreotide
- Carcinoid Syndrome
- Variceal Bleeds
Bile
- Synthesized Continuously By Hepatocytes
- Cholesterol 7 Alpha-Hydroxylase Rate Limiting Step
- Stored In Gallbladder
- Secreted Into Duodenum
- Bile Salts Reabsorbed In Terminal Ileum
- Returned To Liver Via Portal Circulation
- Bilirubin
- Bile Salts
- Cholesterol And Phospholipids
- Ions And Water
Bilirubin Metabolism Overview
- Unconjugated Bilirubin
- Bound to Albumin
- Heme
- Red Blood Cells
- Macrophages
- Conjugated Bilirubin
- Secreted into Bile
- Urobilinogen
- Eliminated in Feces
- Eliminated in Urine
- Enterohepatic Circulation