Create an account
order of events in digestion
ingestion -> digestion -> absorption -> transport -> metabolism -> excretion
Gastrointestinal tract (GI tract)
flexible muscular tube from mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus
circular muscle surrounding and able to close a body opening; help regulate flow of food particles
portion of digestive tract that grinds and churns swallowed food, mixing it with acid and enzymes to form chyme; adds HCL, enzymes, and fluid to bolus; major site of protein digestion
separates stomach from small intestine and regulates the flow of partially digested food into the small intestine; prevents backflow from small intestine back into stomach; opens about 3x per minute
10 ft length; major site of carb and lipid digestion and of nutrient absorption into blood stream and lymphatic system
reabsorbs water & minerals from chyme and leaves semi-solid waste composed of fiber, bacteria, and unabsorbed nutrients; passes waste & unabsorbed nutrients like fiber on to rectum for elimination
periodic squeezing/contracting or partitioning of intestine at intervals along its length
what is the purpose of segmentation?
to mix chyme and promote close contact with digestive juices & absorptive cells of intestinal wall before contents move along
how do digestive enzymes catalyze hydrolysis reactions?
by splitting reactant into 2 products (with addition of water) then molecule is broken into smaller pieces
organs with glands that provide digestive secretions
salivary glands, stomach, pancreas, liver (via gallbladder), small intestine
emulsifier that prepares fats/oils for digestion by bringing fats into suspension with water so that enzymes can break them down into their component parts
tubular glands that lie between the intestinal villi and secrete intestinal juices into the small intestine
when nutrients need specific carrier to transport them from one side of cell membrane to other
when some nutrients must be absorbed actively-these nutrients move against a concentration gradient, which requires energy
what nutrients enter vascular system directly?
amino acids, monosaccharides, & small lipid particles
what nutrients have to enter vascular system via lymphatic system?
larger lipids (monoglycerides, long chain FAs, and fat sol. vit.)
blood circulatory system through which blood lows continuously, picking up and delivering materials as needed
loosely organized system of vessels/ducts that move fluids toward thorasic duct then to vena cave of the heart
clear yellowish fluid almost identical to blood BUT does not contain RBCs or platelets; transports fat and fat soluble vit. to bloodstream
how do long chain FAs and fat-sol vit. absorb into vascular system?
small intestine -> lymp -> vascular system
maintenance of constand internal conditions by body's control systems; constantly react to external forces to maintain limits set by body needs
hormone secreted by cells in stomach wall; turned on by presence of protein in stomach; turned off when stomach reaches pH of 1.5
what causes secretin production?
presence of chyme in small intestine triggers release-pyloric sphincter opens, releasing chyme into duodenum
what happens when CCK reaches pancreas?
it stimulates it to secrete its juices, releasing bicarbonate and enzymes into small intestine which slows gastric motility
gastric inhibitory peptide
slows digestion to allow time for fat digestion; slows GI motility; slows gastric secretions
how does gastric inhibitory peptide travel?
travels from small intestine (via vascular system) to the stomach
how does bicarbonate travel?
travels from pancreas (via vascular system) to small intestine (near pyloric sphincter)
what organs release proteases, lipases, carbohydrases?
secreted by both small intestine (duodenum) and pancreas
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together