The afternoon bell rings. Thirty students pile out of the classroom, hurry down the hall, and step outside into dazzling sunshine. Some smile up at the brilliant blue sky, while others squint and reach for their sunglasses, but a few have another reaction—a…a…achoo!
Does that scenario sound familiar? If not, this could come as a news flash—some people sneeze whenever they are suddenly exposed to bright light. Scientists call this condition the photic sneeze reflex (PSR).
An Age-Old Mystery
People have been trying to sniff out the truth about "sun sneezing" for millennia. More than 2,000 years ago, scholars in ancient Greece proposed an explanation, and people have postulated other theories since then. Even today, however, scientists aren't entirely sure what causes it, partly because medical researchers focus a lot more attention on harmful diseases than sunny sneezes.
The Reason for the Sneezin'
Most experts believe photic sneezes result from some mixed-up signals to the brain. Two nerves with different functions, the trigeminal and optic nerves, happen to be neighbors. When the trigeminal nerve senses irritants, such as dust or pepper, in your nose, it sends a message to your brain, and you sneeze to expel the troublesome stuff. Nearby is the optic nerve, which sends messages from the eyes to the brain. Bright light stimulates the optic nerve and usually makes people's pupils contract. But, for photic sneezers, it may have another effect, too. Scientists theorize that the electrical signal traveling through the optic nerve gets picked up by the trigeminal nerve as well. The body reacts as if something is irritating the nose, triggering a sneeze.
Who Has ACHOO?
While there hasn't been a lot of reliable research on the subject, it's estimated that between 10 and 35 percent of the population has PSR. The trait is passed down genetically, and it's dominant, meaning people can inherit it if one or both of their parents has it. The genetic nature of the condition is reflected in its alternative name, autosomal-dominant compelling helio-ophthalmic outburst syndrome. That name might sound like a terribly technical tongue twister, but its acronym is easy to remember and pronounce—ACHOO!
Based on the article, which of these is true?
A.The trigeminal and optic nerves have very similar functions.
B.Scientists do not devote much research to sunny sneezes because they are harmless.
C.Scientists agree that more than half of the population experiences sunny sneezes.
D.The trigeminal and optic nerves are located far apart in the body.
A.The trigeminal and optic nerves have very similar functions.
wrong
B.Scientists do not devote much research to sunny sneezes because they are harmless.
QUESTION 2
QUESTION 2
2 / OF4
Which is most important to include in a summary of this article?
A.Experts think that the photic sneeze reflex (PSR) affects 10 to 35 percent of people.
B.The trigeminal and optic nerves send electrical signals to the brain.
C.Some people sneeze in bright light when two nerves get their signals crossed.
D.Scholars in ancient Greece proposed an explanation for "sun sneezing" 2,000 years ago.
C.Some people sneeze in bright light when two nerves get their signals crossed.
Which is the closest antonym for the word stimulate, as it is used in the article?
A.staple
B.strengthen
C.streamline
D.stifle
D.stifle
Which passage from the article best supports the idea that sunny sneezes are inherited?
A.The genetic nature of the condition is reflected in its alternative name, autosomal-dominant compelling helio-ophthalmic outburst syndrome.
B.Scientists theorize that the electrical signal traveling through the optic nerve gets picked up by the trigeminal nerve as well.
C.Even today, however, scientists aren't entirely sure what causes it, partly because medical researchers focus a lot more attention on harmful diseases than sunny sneezes.
D.When the trigeminal nerve senses irritants such as dust or pepper, in your nose, it sends a message to your brain, and you sneeze to expel the troublesome stuff.