Digestive System
1. What is digestion?
2. How different are
intracellular and extracellular
digestion? What is the
evolutionary advantage of
extracellular digestion?
3. How is extracellular
digestion related to cellular
and tissue specialization?
4. What is the difference
between a complete digestive
system and an incomplete
digestive system? How are
these types of digestive tubes
associated or not to
extracellular digestion?
5. What are some evolutionary
advantages of animals with
complete digestive tube?
6. What is mechanical
digestion? In molluscs,
arthropods, earthworms, birds
and vertebrates, in general,
which organs respectively
participate in this type of
digestion?
7. Concerning extracellular
digestion what is meant by
chemical digestion?
8. Which type of chemical
reaction is the breaking of
macromolecules into smaller
ones that occurs in digestion?
What are the enzymes that
participate in this process
called?
9. Which organs of the body
are part of the human
digestive system?
10. What are peristaltic
movements? What is their role
in human digestion?
11. From the lumen to the
external surface what are the
tissues that form the digestive
tube wall?
12. What is the location of the
salivary glands in humans?
13. What is the approximate
pH of the salivary secretion?
Is it an acid or basic fluid?
What are the main functions
of saliva?
14. What is the salivary
digestive enzyme? Which type
of food does it digest and into
which smaller molecules does
it transform the food?
15. Why doesn't the food
enter the trachea instead of
going to the esophagus?
16. Is the esophagus a
muscular organ? Why even in
a patient lying totally flat on a
hospital bed can the
swallowed food reach the
stomach?
17. What is the route of the
ingested food from swallowing
until the duodenum?
18. What is the valve that
separates the stomach from
the esophagus called? What is
its function?
19. What is the valve that
separates the duodenum from
the stomach called? What is
its function?
20. What is the pH inside the
stomach? Why is there a need
to keep that pH level? How is
it maintained? Which are the
cells that produce that pH?
21. Besides being fundamental
for the activation of the main
gastric digestive enzyme how
does HCl also directly
participate in digestion?
22. How is the gastric mucosa
protected from the acid pH of
the stomach?
23. What is the digestive
enzyme that acts within the
stomach? Which type of food
does it digest? What are the
cells that produce that
enzyme?
24. What name does the food
bolus that passes from the
stomach to the duodenum
get?
25. Which are the three parts
of thes mall intestine?
26. By generally dividing food
into carbohydrates, fats and
proteins and considering the
digestive process until the
pylorus (exit of stomach),
which of these mentioned
types of food have already
undergone chemical
digestion?
27. What is the substance
produced in the liver that acts
in the small intestine during
digestion? How does that
substance act in the digestive
process?
28. What is the adnexal organ
of the digestive system in
which bile is stored? How
does this organ react to the
ingestion of fat rich food?
29. What are the digestive
functions of the liver?
30. Besides the liver which is
the other adnexal gland of the
digestive system that releases
substances in the duodenum
participating in extracellular
digestion?
31. How does the pancreatic
juice participate in the
digestion of proteins? What
are the involved enzymes?
32. How does the pancreatic
juice resume the digestion of
carbohydrates? What is the
involved enzyme?
33. How does the pancreatic
juice help the digestion of
lipids? What is the involved
enzyme?
34. Besides the pancreatic
juice in the intestine there is
the releasing of the enteric
juice that contains digestive
enzymes too. What are these
enzymes and which type of
molecule do each of these
enzymes break?
35. Coming from the acid pH
of the stomach which pH level
does the chyme find when it
enters the duodenum? Why is
it necessary to maintain that
pH level in the small intestine?
What are the organs
responsible for that pH level
and how is it kept?
36. What are the five human
digestive secretions? Which of
them is the only pne that does
not contain digestive
enzymes?
37. Why do protease supplying cells of the stomach
and of the pancreas make only
precursors of the active
proteolytic enzymes?
38. After digestion the next
step is absorption done by
cells of the mucous membrane
of the intestine. For this task a
large absorption surface is an
advantage. How is it possible
in the small internal space of
the body of a pluricellular
organism to present a large
intestinal surface?
39. In which part of the
digestive tube is water is
chiefly absorbed? What about
the mineral ions and vitamins?
40. From the intestinal lumen
through to the tissues - what
is the route of nutrients after
digestion?
41. What is the special route
that lipids follow during
digestion? What are
chylomicrons?
42. What are the so-called
“good”and “bad” cholesterol?
43. Why does the ingestion of
vegetable fibers improve the
bowel habit in people that
suffer from hard stools?
44. What are the main
functions of the bacterial flora
within the human gut?
45.The releasing of digestive
secretions is controlled by
hormones. What are the
hormones that participate in
this regulation?
46. How is it produced and
what is the function of gastrin
in the digestive process?
47. Where is it produced and
what is the function of
secretin in the digestive
process?
48. How is it produced and
what is the function of
cholecystokin in the digestive
process?
49. Where is it produced and
what is the function of
enterogastrone in the
digestive process?
50. What are the special
structuresof the avian
digestive tube and their
respective functions?
51. Compared to mammals do
birds absorb more or less
water in their digestive
system? Why is this
phenomenon an adaptation to
flight?
52. What is meant by
“mutualist exploration of
cellulose digestion”, a
phenomenon that occurs in
some mammals and insects?
53. Cows swallow their food
once and then this food goes
back to the mouth to be
chewed again. How can this
phenomenon be explained?