TEDVIDEO The surprising reason you feel awful when you're sick

What are the initial symptoms of the flu?

• Muscle aches, irritability, and loss of appetite

• A tickle in your throat and a cough

• Sleepiness, fever, and dehydration

• None of the above

What happens when a pathogen like the flu virus enters your body?

• Your body's immune system is activated when it detects a problem.

• You immediately feel sick

• Your muscles begin to ache

• None of the above

What is the role of macrophages in fighting infection?

• Macrophages release cytokines to bring in more cells that fight off viruses.

• They search for and destroy viruses and infected cells

• They coordinate with the brain to launch a stronger attack

• None of the above

Why does the immune system sometimes launch a stronger attack against viruses?

• To avoid the spread of viruses into the blood and vital organs

• To make you feel more uncomfortable

• To cause a rise in body temperature

• None of the above

What is the role of cytokines in causing unpleasant symptoms?

• They trigger two responses that cause a rise in body temperature and sleepiness

• They help your immune system destroy pathogens

• They increase your sensitivity to infected cuts.

• None of the above

How does a higher body temperature help in healing?

• It slows bacteria and helps your immune system destroy pathogens

• It makes you more sensitive to infected cuts

• It causes a reduction in thirst

• None of the above

What is the purpose of sleep during illness?

• To let your body channel more energy towards fighting infection

• To help your immune system destroy pathogens

• To starve bacteria by reducing iron in your blood

• None of the above

How does sickness affect the brain?

• It makes you more irritable, sad, and confused

• It affects areas like the limbic system and cerebral cortex

• all of the above

What causes autoimmune diseases?

• The immune system treats normal bodily cues as threats

• Millions of years of evolution

• Adjusting the immune system precisely.

• None of the above