Digestive System Flashcards
SI Sections
Duodenum, Jejunum, Ileum
Swallowing (Deglutition)
Voluntary (skeletal), Involuntary (smooth)
Mechanical Digestion
Teeth, chewing -> creates bolus
Chemical Digestion
Saliva, much, stomach acid
Sphincter
Guards openings, circular, lower esophageal sphincter
Stomach Muscle Layers
Longitudinal, circular, oblique
Essential Nutrient
Have to consume (9 AAs)
Nonessential Nutrient
Can be made in body
Ampula of Vader
Bile and Pancreas Enzymes mix
Gut flow Produced Vitamins
B1-B3, B12, K
Stomach
Initial digestion and storage of food
Stomach Acid Secretion
Chemical breakdown, inactivate toxins, destroy bacteria
Cardiac Sphincter
Allows food to enter from the esophagus, prevents regurgitation
Pyloric Sphincter
Prevents solid food from passing into the intestine, opens to release chyme
Chyme
low pH liquid slurry
Rugae of Mucosa
Extensions in the stomach for storage
Gastric Glands
Tubular glands in the stomach wall, secrete about 2 liters of gastric juice a day
Chief Cells
Secrete pepsinogen
Pepsin
activated by acidic environment, splits certain peptide bonds and releases amino acids, present in the stomach of vertebrates
Mucous Cells
Secrete mucous
Parietal Cells
Secrete HCl, IF
HCl
Chloride shift in blood
IF
Aids in Ca2+ uptake, reabsorbs B12
G Cells
Secrete hormone gastrin into the bloodstream
Rennin
“chymosin”, a milk-curdling enzyme, found in stomachs of nursing-age ruminants
Cephalic Stage
Food recognition
Gastric Stage
Muscle contraction
Hepatocytes
Liver Cells
Liver
Storehouse for glycogen produces proteins, detoxifies, metabolism of fat, produces bile
Bile
Secreted by the liver, stored in the gall bladder, and transported to small intestine, contains water, salts, phospholipids, reduces fat droplets to smaller sizes
Trypsin/Chymotrypsin
Proteases that split apart peptide bonds
Carboxypeptidase
Removes amino acids from carboxyl ends of polypeptides
Pancreatic Lipase
Hydrolyzes fats into fatty acids and glycerol
Pancreatic Amylase
Starch-splitting enzyme identical to salivary amylase
Nucleases
Degrade RNA and DNA to nucleotides
Villi
Minute finger-like projections of lining present in some vertebrates
Microvilli
Highly folded regions on the free surface of lining cells
Main Carbohydrates
Glycogen, starch, cellulose, chitin
HDL
Low Cholesterol, High Protein
LDL
High Cholesterol, Low Protein
VLDL
Very low-density lipoprotein
Large Intestine
Consolidates undigested material as semisolid feces, reabsorption of water is an important large intestine function, 1/3 of dry weight is bacteria
Gastrin
Small polypeptide hormone, produced by endocrine cells in the pyloric stomach (G cells), stomach produces and stomach target
CCK
Secreted by endocrine cells in the wall of the upper small intestine in response to fatty acids and amino acids in the duodenum, stimulates the release of bile and pancreatic secretions
Secretin
1st hormone identified, produced by endocrine cells in the duodenal wall, secreted in response to food and strong acid in the stomach and small intestine, aids fat digestion by inhibiting gastric motility and increasing bile secretion from liver