Why We Get Sick

Question 1

Proximate explanation

Answer 1

Answers the question what or how

Ex: anemia- in presence of infection, body lowers iron availability in blood

Question 2

Ultimate explanation

Answer 2

Answers the question why

Ex: anemia- body withholds iron because iron is a crucial resource for bacteria, so short term anemia helps fight infection

Question 3

Examples of defenses to disease

Answer 3

Vomiting, diarrhea, cough- gets disease out
Fever- kills disease
Anemia- denies resources the disease needs

Question 4

Fitness is actually measured by…

Answer 4

Reproductive success (passing on genes)

Question 5

Signs vs symptoms

Answer 5

Signs are objective, can be known without the patient saying anything

Question 6

Acute vs chronic

Answer 6

Acute- temporary symptoms or sudden onset

Chronic- long term

Question 7

Mechanisms of disease (8)

Answer 7

1. Genetic- mutations
2. Pathogens- viruses, etc
3. Cancer
4. Physical or chemical agents- toxins
5. Malnutrition- scurvy
6. Autoimmunity
7. Inflammation- can happen at inappropriate times
8. Degeneration- aging

Question 8

Darwin’s idea of natural selection (4)

Answer 8

1. Variation among individuals
2. Some variation is inherited
3. Populations produce more offspring than the environment can support
4. Individuals with the most adaptive traits will be more likely to survive and have offspring

Question 9

Negative feedback loop

Answer 9

Opposes stimulus

Ex: regulation of body temperature

Question 10

Positive feedback loop

Answer 10

Reinforces feedback loop

Ex: birth

Question 11

Components of a feedback loop

Answer 11

1. Receptor- monitors changes and sends input to control center
2. Control center (usually brain)- set range of values, evaluates input and generates output commands
3. Effector- receives output from control center, produces a response to change condition