1. Ulcers Models and Evidence Continue

2. With your partner, read through the slides to learn about ulcers. Remember, read carefully so you are able to answer questions. Whenever you have a discussion, try to agree on both your answers and your reasons with your partner! BackContinue

3. Introduction: BackContinue Ulcers are sores in the stomach. Many millions of Americans suffer from ulcers. They can be very painful. Scientists want to find out why people get ulcers so that they can try to help them. You will examine evidence to try to figure out how people get ulcers. Problem: Why do people get ulcers?

4. Right now scientists have two main models that explain how people get ulcers. Their models are on the next slide. BackContinue

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6. Now you’ll see some evidence to help you decide which model is better. Don’t forget to read carefully so you can answer questions about the evidence! When answering questions, be sure to try to agree on both your answers and reasons. BackContinue

7. Evidence 1 BackContinue Scientists studied the amount of acid in the stomachs of two groups of people: those who have ulcers and those who don’t. They have found that people with ulcers produce more acid in their stomachs than people without ulcers. The results for the two groups are shown in the following graph:

8. Question 1 and 2: Arrows Think about how this evidence relates to each of the models that you have seen. On your blue sheet, draw in the arrow that you think best connects this evidence to each of the models. Draw your arrow for Model A in the first column and your arrow for Model B in the second column. BackContinue

9. Question 3: Based on the evidence, people with ulcers: a. have less acid in their stomach than people without ulcers b. have just as much acid in their stomach as people without ulcers c. have slightly more acid in their stomach than people without ulcers d. have much more acid in their stomach than people without ulcers Answer these 2 questions about Evidence 1. Write the letter of your best answer on your blue sheet. Be sure to discuss your answers and your reasons with your partner. Question 4: Which is true of Evidence 1? a. Scientists studied the amount of acid in people’s intestines. b. The amount of acid is easy to measure. c. There is a clear difference between people with and without ulcers. d. The people in the study were people who have very serious ulcers and people who have less serious ulcers. BackContinue

10. Evidence 2 BackContinue The Centers for Disease Control and Prevention (CDC) in the USA has presented the table below showing some of the most stressful and least stressful jobs people have: Most Stressful JobsLeast Stressful Jobs Police OfficerForester MinerBookbinder Air Traffic ControllerSales representative Emergency Room doctorTherapist According to the CDC, people with any of these jobs have the same likelihood of getting ulcers.

11. Question 1 and 2: Arrows Think about how this evidence relates to each of the models that you have seen. On your blue sheet, draw in the arrow that you think best connects this evidence to each of the models. Draw your arrow for Model A in the first column and your arrow for Model B in the second column. ContinueBack

12. Answer these 2 questions about Evidence 2. Write the letter of your best answer on your blue sheet. Be sure to discuss your answers and your reasons with your partner. BackContinue Question 3: Based on the evidence: a. a miner is a less stressful job than a forester b. a therapist is a less stressful job than a sales representative c. an emergency room doctor is a less stressful job than an air traffic controller d. a bookbinder is a less stressful job than a police officer Question 4: According to the CDC: a. people with the least stressful jobs are more likely to get ulcers b. people with the most stressful jobs are more likely to get ulcers c. there is no connection between the stressfulness of a job and likelihood of getting an ulcer d. every job is different in likelihood of getting ulcers

13. Evidence 3 Scientists have found that acid is important in keeping harmful bacteria out of the stomach. In one study, scientists placed 4 different types of bacteria in acid taken from the stomachs of normal people. Within 30 minutes, 99.9% of the bacteria had died. In another study, scientists placed 4 types of bacteria in acid from people who suffered from a condition called “pernicious anemia” that caused their acid to become weak and not function properly. In these people, the bacteria did not die. They even multiplied. BackContinue

14. Question 1 and 2: Arrows Think about how this evidence relates to each of the models that you have seen. On your blue sheet, draw in the arrow that you think best connects this evidence to each of the models. Draw your arrow for Model A in the first column and your arrow for Model B in the second column. BackContinue

15. Answer these 2 questions about Evidence 3. Write the letter of your best answer on your blue sheet. Be sure to discuss your answers and your reasons with your partner. BackContinue Question 3: Pernicious anemia causes: a. acid to become stronger b. acid to become weaker c. the stomach to become smaller d. the stomach to become larger Question 4: When placed in acid from the stomachs of normal people: a. 0.1% of the bacteria had died b. 99.9% of the bacteria had died c. all of the bacteria had died d. none of the bacteria had died

16. Evidence 4 BackContinue Using powerful microscopes, scientists examined the lining of the stomachs of 500 people to see if any bacteria could live there. They examined people between the ages of 15 and 60. In 80% of people with ulcers, they found bacteria like the ones shown below inside the lining of their stomachs. The bacteria is a species called Helicobacter pylori (H. pylori).

17. Question 1 and 2: Arrows Think about how this evidence relates to each of the models that you have seen. On your blue sheet, draw in the arrow that you think best connects this evidence to each of the models. Draw your arrow for Model A in the first column and your arrow for Model B in the second column. ContinueBack

18. Answer these 2 questions about Evidence 4. Write the letter of your best answer on your blue sheet. Be sure to discuss your answers and your reasons with your partner. BackContinue Question 3: From the evidence, you know that the people who were examined: a. had ulcers b. did not have ulcers c. were between the ages of 15 and 60 d. came from the same location Question 4: Based on this evidence, you can conclude that: a. all the people had bacteria in their stomach lining b. none of the people had bacteria in their stomach lining c. some of the people had bacteria in their stomach lining d. each person had different bacteria

19. Evidence 5 BackContinue Penicillin is a type of medicine that kills many types of bacteria. Zantac is a medicine that makes the acid in the stomach weaker. Scientists gave 500 people with ulcers penicillin. They gave 500 other people with ulcers Zantac. Then the scientists stopped the medicine to see what happened. This is what they found: Before taking the medicine While on the medicine1 week after taking the medicine People who took penicillin 98% felt ulcer pain40% felt ulcer pain9% felt ulcer pain People who took Zantac98% felt ulcer pain28% felt ulcer pain94% felt ulcer pain

20. Question 1 and 2: Arrows Think about how this evidence relates to each of the models that you have seen. On your blue sheet, draw in the arrow that you think best connects this evidence to each of the models. Draw your arrow for Model A in the first column and your arrow for Model B in the second column. BackContinue

21. Answer these 2 questions about Evidence 5. Write the letter of your best answer on your blue sheet. Be sure to discuss your answers and your reasons with your partner. BackContinue Question 3: According to this evidence, which is true for most people with ulcers? a. Zantac cures them. b. Zantac makes them feel better but does not cure them. c. Penicillin makes them feel better but does not cure them. d. None of the above. Question 4: After stopping the medicine, people on Zantac: a. felt better than those who had taken penicillin b. felt no difference than those who had taken penicillin c. felt worse than when they had been on the medicine d. were totally cured

22. Now, wait for your teacher’s instructions. Back