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Other Defences • Team & blinking of eyes, pain, hormones. (Adrenalin
released. When body stressed).

Cellular Mechanisms
The Cells of the body possess their own defence systems.

Table 2: Defence mechanisms of cells.

Scavenging action A type of white blood cell called macrophages attack invading
particles in order to destroy them and remove them from the body.
This process is known as phagocytosis.
Secretion of defensive Is done by some specialised cells.
substances
Adrenaline is a hormone produced by the adrenal glands during
high stress or exciting situations. This powerful hormone is part of
the human body's acute stress response system, also called the
"fight or flight" response. It works by stimulating the heart rate,
contracting blood vessels, and dilating air passages, all of which
work to increase blood flow to the muscles and oxygen to the lungs.

Histamine is a chemical in the body that is released when the body
is exposed to an allergen. Allergens may include airborne allergens
(such as pollen and dust mites), certain foods (such as peanuts and
shellfish) or insect venom. Histamine is released in an effort to
protect the body from an allergen; however, sometimes an
overload of histamine can result in life- threatening symptoms.

Prevention of excessive Reduced circulation through blood clotting and coagulation
blood loss prevents excessive bleeding and slows or prevents the entry of
bacteria.

Heparin is an anticoagulant (blood thinner) that prevents the
formation of blood clots and is produced naturally in the lungs
and liver.

Repair of damaged Is a necessary defence mechanism which includes removal of dead
tissues cells, increased availability of defender cells and replacement of
tissue strength, for example, scar tissue caused by silica.

ENSIGN| Unit IG2 – Element 7 – Chemical and Biological 14
Agents