Pollen
Small, light, dry protein particles from trees, grasses, flowers, and weeds that may be spread by the wind. Pollen particles are usually the male sex cells of a plant, and they are smaller than the tip of a pin. Pollen is a potent stimulator of allergic responses. It lodges in the mucous membranes that line the nose and in other parts of the respiratory tract, causing irritation and histamine reactions.
Read Also:
- Pollen count
The number of pollen grains landing on a given area during a specified time. The count is taken by a spinning rod that moves through the air at certain intervals. The pollen grains that stick to the rod are specially stained and examined through the microscope. Technically, pollen grains are the small male reproductive bodies […]
- Polony
A tiny colony of DNA, about one micron in diameter. The word “polony” is a contraction of “polymerase colony.” To create polonies, a solution containing dispersed DNA fragments is poured onto a microscope slide. An enzyme called DNA polymerase is added. It causes each fragment to copy itself repeatedly, creating millions of polonies, each dot […]
- Poly-
Short form for polymorphonuclear leukocyte, a type of white blood cell.
- Polyarteritis nodosa
An autoimmune disease that is characterized by spontaneous inflammation of the arteries (arteritis) and can affect any organ of the body. Polyarteritis nodosa most commonly affects muscles, joints, intestines, nerves, kidneys, and skin. Inflammation of the arteries can lead to inadequate blood supply and permanent damage to organs. Typically, polyarteritis nodosa is treated with medications […]
- Polyarticular
Involving many joints, as opposed to monoarticular (affecting just one joint).