Digestive System Flashcards
Mucous Surface Cells:
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Tonic secretion; irritation of the mucosa
2) Mucus
3) Physical Barrier between lumen and epithelium
Mucous Neck Cells:
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Secreted with mucus
2) Bicarb
3) Buffers gastric acid to prevent damage to the epithelium
Parietal Cells (Gastric Acid/HCl)
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, gastrin, histamine
2) Gastric Acid (HCl)
3) Activates pepsin; kill bacteria
Parietal Cells (Intrinsic Factor)
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, gastrin, histamine
2) Intrinsic Factor
3) Complexes with vitamin B12 to permit absorption
Enterochromaffin-like Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, gastrin
2) Histamine
3) Stimulate gastric acid secretion
Chief Cells (Pepsin(ogen))
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, acid secretion
2) Pepsin
3) Digest proteins
Cheif Cells (Gastric Lipase)
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, acid secretion
2) Gastric Lipase
3) Digest fats
D-Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Acid in the stomach
2) Somatostatin
3) INHIBITS gastric acid secretion
G-Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Ach, peptides, amino acids
2) Gastrin
3) STIMULATES gastric acid secretion
I-Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Fatty acids, some amino acids
2) Cholecystokinin (CCK)
3) Stimulates gallbladder contraction + pancreatic enzyme secretion; inhibits gastric emptying and acid secretion
S-Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Acid in the small intestine
2) Secretin
3) Stimulates bicarb secretions; inhibits gastric emptying + acid secretion
K-Cells
1) Stimulus?
2) Substance Secreted?
3) Function of Secretion
1) Glucose, fatty acids, and amino acids in the small intestine
2) Gastric Inhibitory Peptide (GIP)
3) Stimulates insulin release; inhibits glucagon release and gastric function
Oral Cavity and Esophagus:
Secretion
Digestion
Absorption
Motility
S: Saliva
D: Carbohydrates
A: None
M: Chewing & Swallowing
Stomach:
Secretion
Digestion
Absorption
Motility
S: HCl, Pepsinogen (parietal), Gastric Lipase (chief), Mucus and bicarbonate (surface mucous), histamine (ECL)
D: Proteins, Fats (minimal)
A: Lipid-soluble substances (alcohol and aspirin)
M: Peristaltic mixing and propulsion
Small Intestine:
Secretion
Digestion
Absorption
Motility
S: Enzymes (enterocytes), mucus (goblet); hormones: CCK, secretin, GIP, and others (endocrine); Enzyme and bicarbonate (exocrine pancreas); Bile (liver + stored in the gallbladder
D: Polypeptides, carbs, fats, nucleic acids
A: Amino acids and small peptides; monosaccharides, fatty acids, monoglycerides, cholesterol; nitrogenous bases; water; ions, minerals, vitamins
M: Mixing and propulsion primarily by segmentation; some peristalsis
Large Intestine:
Secretion
Digestion
Absorption
Motility
S: Mucus (goblet cells)
D: None (except bacteria)
A: Ions, minerals, vitamins; water; small organic molecules made by gut bacteria
M: Segmental mixing; mass movement for propulsion
Gastric Juice pH
~2
Bicarb barrier pH
~7
Common Hepatic Duct
takes bile made in the liver to the gallbladder for storage
Common Bile Duct
takes bile from the gallbladder to the lumen of the small intestine
Hepatic Artery
brings OXYGENATED blood containing metabolites from peripheral tissues to the liver
Hepatic Portal Vein
blood rich in absorbed nutrients from the gastrointestinal tract and contains hemoglobin breakdown products from the spleen leaves liver through here
Sphincter of Oddi
controls release of bile and pancreatic secretions into the duodenum
What is absorbed from the gastrointestinal tract and goes TO the liver via the hepatic portal vein?
bilirubin
nutrients
drugs
foreign substances
What metabolites and drugs from peripheral tissues goes TO the liver via the hepatic artery?
bilirubin
metabolites of hormones and drugs
nutrients
What is secreted into the duodenum FROM the liver through the bile duct?
bile salts
bilirubin
water, ions
phospholipids
What metabolites are sent to the peripheral tissues FROM the liver through the hepatic vein?
glucose
plasma proteins: albumin, clotting factors, angiotensinogen
Urea
Vitamin D, somatomedins
Metabolites
What processes happen in the liver?
glucose and fat metabolism
protein synthesis
hormone synthesis
urea production
detoxification
storage
Secretion
movement of material from cells into lumen or ECF
Digestion
chemical and mechanical breakdown of food into absorbed units
Absorption
movement of material from GI lumen to ECF
Motility
movement of material through the GI tract as a result of muscle contraction
