Q 01/05

Neurotransmitters are released by one neuron and picked up by receptors on the next: what exactly are they?

A) Electrical impulses

B) Chemical messengers

C) Structural proteins

D) Immune cells

Answer · why

B) Chemical messengers

Chemical messengers are how neurons signal across the tiny gap between them. Scientists know of at least 100 neurotransmitters and suspect many others...

Q 02/05

Death of dopamine-producing neurons in the brain's substantia nigra causes which movement disorder?

A) Parkinson's disease

B) Huntington's disease

C) Multiple sclerosis

D) Tourette syndrome

Answer · why

A) Parkinson's disease

Parkinson's disease is spotted late in the damage: by the time movement symptoms appear, 50–80% of the dopamine neurons in the substantia nigra have a...

Q 03/05

Wrinkle-smoothing injections block acetylcholine release using a diluted form of the toxin behind which illness?

A) Tetanus

B) Anthrax

C) Botulism

D) Diphtheria

Answer · why

C) Botulism

Botulism is the paralysing illness caused by botulinum toxin, the active ingredient of Botox. By stopping nerve endings releasing acetylcholine, it re...

Q 04/05

Serotonin is famous as a mood transmitter, but about 90% of the body's supply is made where?

A) The brain

B) The liver

C) The heart

D) The gut

Answer · why

D) The gut

The gut makes most of it: enterochromaffin cells in the gastrointestinal tract produce serotonin, which regulates intestinal movements.

Q 05/05

Caffeine keeps people alert by blocking the brain's receptors for which sleepiness-promoting molecule?

A) Adenosine

B) Melatonin

C) Serotonin

D) Dopamine

Answer · why

A) Adenosine

Adenosine builds up in the brain during waking hours, creating the need to sleep. Caffeine has a similar three-dimensional structure, so it binds to t...