Sunday, August 25, 2019
ABS 394
Subtopic 2B!
•How can cows digest the cellulose in grass and get the nutrients they
need, whereas dogs cannot, even though neither of these animals
produces an enzyme called cellulase which is required to break down
cellulose?
Cows have microorganisms in their gut to break down cellulose.
•Where does digestion of starches start in the human digestive system?
What enzyme is involved?
It starts in the mouth with salivary amylase.
•What is gastric juice? What is it made up of?
It is used in the stomach to mix and churn food. It is made up of a
concoction of enzymes and acid. It is mostly made up of hydrochloric
acid, an enzyme called pepsin, and some mucus and water.
•What are two functions of the stomach acid
(hydrochloric acid)?
The acid breaks things down and kills most of the bacteria.
•What is one likely result if our stomachs do not produce enough mucus?
It is there to protect the stomach from digesting itself. You can get peptic
ulcers if you lack mucus.
•What is the function of the appendix?
It is to act as a safe house for all the good bacteria you need to help you
digest your food.
•What pushes the food down our esophagus into our stomachs when we
swallow food?
The contractions of muscles pushes food further down.!
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Sunday, August 25, 2019
• What is the size of an average human stomach when it is empty and when it is
full?
The average human stomach can expand from the size of a small apple from when its empty to
about 2 liters when full.
•What is the function of the digestive enzymes in our guts?
Digestive enzymes from the pancreas and gallbladder induce chemical
reactions to break food down into nutrients that the body readily absorbs.
•How large would be the surface area of the small intestine (small bowel)
if completely unfolded? Why is it so large?
It can be as large as a tennis court size. It is so large because there is a
huge amount of work that goes on in there.
•What is the primary function of the blood vessels lining the small
intestinal wall?
It is required for a healthy blood supply. It picks up digested nutrients
and transports them all over the body.
•What is the main function of the blood vessels lining the walls of the
colon (large intestine)?
It is used to draw out water from the feces.
•What enzyme is required to digest cellulose, the material that makes up
the walls of plant cells?
cellulase
•Which organisms produce the enzyme that can break down cellulose?
bacteria
•What part of the digestive system of herbivores is most cellulose
digested? How large is this part compared to carnivores?
cecum. It is larger in herbivores than carnivores.
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Sunday, August 25, 2019
•What does the fecal matter of true herbivores look like? What is one
behavioral characteristic of herbivores that is related to their own fecal
matter?
pellets. Herbivores re-ingest cecal pellets to absorb more nutrients from
that digested cellulose.
•How does the length of the digestive system of a carnivore compare to
that of a herbivore?
the stomach is smaller due to the high nutrient density in meats. The
small intestine in carnivores is relatively short compared to herbivores.
That is to allow for a quick transition time of when food is coming in and
going out. That reduces the opportunity for flesh to decay in the actual
gut and reduces the likelihood of an infection. The large intestine is
relatively short and simple. The main purpose is to absorb ions and salts.
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