Chapter 3 Flashcards
What is digestion?
a process where food is broken down into absorbable units
what is the lumen?
the space within a vessel such as the intestine.
GI tract?
the gastrointestinal tract, flexible muscular tube that expands from the mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus.
bolus?
a mouthful of food that has been chewed and swallowed.
chyme?
semiliquid mass of a partly digested food expelled by the stomach into the duodenum.
Where does digestion begin?
in the mouth
order of digestion?
mouth, pharynx, salivary glands, epiglottis, trachea, esophagus, esophagus sphincters, diaphragm, stomach, pyloric sphincter, liver, gallbladder, bile duct, appendix, small intestine, ileocecal valve, pancreas, pancreatic duct, large intestine, rectum, anus.
how many organs are involved?
21
what is a sphincter? how many prevent backflow?
the passage that sends the food from one place to another and helps prevent backflow. three.
how many layers of muscle are in the stomach?
three, longitudinal, circular, and diagonal
three segments of the small intestine?
the duodenum connected to the stomach, the jejunum then the ileum connected to the colon.
what is the appendix?
a narrow, finger-shaped pouch that projects out from the colon.
what does the large intestine absorb?
absorbs water and salt from items that have not been digested, gets rid of the waste leftover.
parts of the large intestine? (colon)
the cecum, ascending colon, transverse colon, descending colon, and sigmoid colon.
what is an enzyme?
protein that facilitates a chemical reaction, making a molecule, breaking a molecule, changing the arrangement of it exchanging.
role of saliva in digestion? gastric juice?
helps lubricate the food so it can go down the esophagus. gastric juice activates digestive enzymes which break down proteins.
purpose of sodium bicarbonate?
protects the duodenum by neutralizing the acid that comes from the stomach.
purpose of bile, where it is produced, and where it is stored?
bile prepares fats and oils for digestion, made by the liver, stored in the gallbladder, and released into the small intestine when needed.
where do most of the absorption of nutrients occur?
small intestine
absorption techniques?
simple diffusion, some nutrients are absorbed like water and lipids, cross into intestinal cells freely.
facilitated transport, some are absorbed like water-soluble nutrients, need a specific carrier to transport them from one side of the cell membrane to the other side.
active transport, some nutrients are absorbed like glucose and amino acids, move against a concentration gradient, require energy.
anatomy of the absorptive system? purpose?
small intestine, villi, fingerlike projections from the folds of the small intestine. microvilli, tiny, hairlike projections on each cell of every villus that can trap nutrient particles and transport them into cells. Crypts, tubular glands that secrete the intestinal juices into the small intestine. globet cells secrete mucus.
the first organ to receive absorbed nutrients from the GI tract?
the liver
probiotics?
live microbes that change conditions in the GI tract in ways that benefit health, alleviate diarrhea, constipation, inflammatory bowel syndrome, ulcers, allergies, etc.
prebiotics?
fibers and some other components that encourage growth and activity of bacteria, reduce GI infections, inflammation, and disorders.
