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Evolution 2nd Edition

Evolution (2nd Edition)

Book Edition2nd Edition
Author(s)Bergstrom, Dugatkin
ISBN9780393937930
PublisherW. W. Norton
SubjectBiology
Section 20.1: Vulnerability to Disease
KEY CONCEPT QUESTION
Section 20.2: Fever
KEY CONCEPT QUESTION
Section 20.3: Coevolutionary Arms Races between Pathogens and Hosts
KEY CONCEPT QUESTION
Section 20.4: Phylogenetics Constraints and Vulnerability to Choking
KEY CONCEPT QUESTION
Section 20.5: Senescence
KEY CONCEPT QUESTION

Chapter 20, Section 20.1, KEY CONCEPT QUESTION, Exercise 20.1

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Explanation

The entry of any irritant or some type of allergens in the mucosal membrane of the nose can cause a reflex action of sneezing. The moment the irritant is detected by the nerves [sinus nerves] in the nose, they send a signal to the brain. Upon receiving the signal, the brain triggers a reflex response in the form of sneezing [air is expelled forcefully through mouth and nose].

 

In evolutionary terms, sneezing can be seen as a cleansing mechanism. In order to clear the nasal passage from any pathogen or irritant, a high-velocity mucous expulsion is produced. Owing to the viscous nature of mucous, the irritant gets trapped within it and comes out of the nose during sneezing, which clears the passage.

Sample Response

The neuron signaling that occurs during the entry of an irritant in the mucosal membrane of the nose results in the sneeze reflex.

 

From an evolutionary point of view, the clearance of the nasal passage by getting rid of any pathogen or irritant is done through the sneeze reflex.

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