You hear the wind blowing and birds calling.
A pine tree appears on the left of the screen.
Allergens like pollen are nothing more than foreign plant antigens.
A man, in profile and shown from the neck up, approaches the tree.
When they get released into the air, you can see and hear the result.
A cloud of pollen is given off by the tree and the man is engulfed. He sneezes.
Silhouette of the man’s head, with the nasal passages shown.
The image zooms in on the nasal cavity.
When allergens first encounter nasal tissue,
sneezing is triggered. This is part of the body’s immune defense.
Pollen enters the nasal cavity.
A close-up of a grain of pollen
Pollen allergens then encounter the plasma cells in the nose,
A plasma cell approaches the grain of pollen.
which respond by producing antibodies.
These antibodies attach to mast cells,
A mast cell approached the plasma cell.
which are white blood cells containing the chemical histamine.
As more antibodies are produced,
they cause the mast cells to release histamine,
which produces allergy symptoms
A close-up of the nasal cavity.
such as a stuffy and runny nose, sneezing, and watery eyes.
These help to remove the invading pollen.
Medications called antihistamines can be used to help
relieve severe allergy symptoms.
Return to the image of the pine tree giving off a cloud
of pollen, engulfing the man. He sneezes.