TEACHER ANSWER KEY
Answer the following questions about information from this unit.
1. What is heartburn? How does it happen? (Think about the structure in the
digestive tract that is close to the heart, and not protected by mucous.)
Heartburn is caused by the highly acidic juices of the
stomach reaching the unprotected tissue of the
esophagus. The esophagus is normally protected
from the stomach by a valve, but as you age this valve
does not function as it should. You are more
susceptible to this after big meals that contain large
quantities of fat, such as pizza.
2. Make a list of foods that humans could not
eat if they did not have a liver? Why not?
Foods with fats: Cheese, meat, fried foods, etc. The liver produces bile that emulsifies the
digested fats into smaller groups of lipid molecules so that they can be broken down by lipases
(fat degradation enzymes).
3. Why can cows eat grass and humans cannot? What do they do different during
digestion than humans? If you have ever seen a cow what are they always doing
with their mouth? Do you think that cows have an extra organ in their digestive
tract to help them digest grass?
Cows can eat grass due to two differences in digestion. First,
cows regurgitate their food into their mouths and chew it
again. Secondly, cows have a digestive enzyme that breaks
down cellulose, the structural protein of plants, whereas
humans do not, so therefore cellulose passes through our
digestive tract. It is more commonly know as dietary fiber.
4. Diabetes is a genetic metabolic disorder that affects all races especially
Hispanics. Diabetes occurs when your cells are not receiving a sufficient amount
of glucose. The prevalent symptoms of diabetes are high blood sugar level and
glucose in the urine. Pretend you are a doctor and you have a patient that displays
these symptoms. Which hormone would you conclude is not being produced?
What organ normally produces this hormone? Can you think of possible ways to
administer the hormone to your patient? When would you think the best time to
administer this hormone would be?
Digestive System: Activity 4
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TEACHER ANSWER KEY
The pancreas does not produce insulin. Insulin can only be administered by a shot. There are
diabetes pills but they only reduce the effects of the symptoms, they are not an alternative to the
insulin shot. If insulin were administered as a pill, it would be denatured in the highly acidic
juices of the stomach. Insulin is needed the most after you have eaten a meal. It must be
administered 3 - 4 times daily.
5. Apply your knowledge and speculate on a general mechanism in the body that
could stimulate the contraction of the diaphragm and the abdominal muscles that
stimulate vomiting. Begin with a trigger/receptor listed in the “What We Know”
section and finish with the muscles that are stimulated. Your mechanism should
list the steps a signal would take to get from the trigger/receptor to the muscles that
make you vomit. You should incorporate your knowledge from other organ
systems mainly the nervous system.
A general hypothesis for this question should include the following:
1.) One of the receptors (Listed in the what we know section on digestion) is triggered and it
signals an adjacent nerve.
2.) The triggered nerve relays the message to the central nervous system.
3.) The message is interpreted by the CNS.
4.) The CNS initiates a signal that is destined for the appropriate body parts to complete the task.
5.) The message travels down a different nerve to the diaphragm and the abdominal muscles
causing them to contract.
Digestive System: Activity 4
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