immune system Flashcards
term immunity refers
to the body’s specific protective response
to a foreign agent or organism.
The immune system functions as
the body’s defence mechanism
against invasio
Disorders of the immune system may stem from
excesses or
deficiencies of immunocompetent cells, alterations in the function of
these cells, immunological attack on self-antigens or inappropriate or
exaggerated responses to specific antigens
PURPOSE OF IMMUNE
SYSTEM
is to defend the body from invasion by any foreign object or foreign cell
type, such as cancerous cells. This is a homeostatic mechanism, but like other
adjustment processes, it can become disordered and cell injury will occur.
The immune response detects
foreign bodies by distinguishing non–self-substances
from self-substances, destroying the non–self-entities. The entrance of an antigen
(foreign substance) into the body evokes the production of antibodies that attack and
destroy the antigen (antigen–antibody reaction)
• The immune system can be hypoactive or hyperactive.
When it is hypoactive,
immunodeficiency diseases occur; when it is hyperactive, hypersensitivity disorders
arise. to
A disorder of the immune system itself can result in damage
the body’s own
tissues. Such disorders are labelled autoimmune diseases
THE IMMUNE SYSTEM
• Protects the body from
pathological bacteria, foreign tissue cells, and cancerous
cells
THE IMMUNE SYSTEM
Made up of
specialised cells and molecules – B cells and T cells
THE IMMUNE SYSTEM PROVIDES IMMUNITY
- Nonspecific immunity
- Natural immunity—
- Acquired immunity
- Artificial immunity—
• Nonspecific immunity
ü Skin—mechanical barrier to bacteria and other harmful agents
• Natural immunity
exposure to causative agent is not deliberate
• Acquired immunity
ü Active—vaccination results in immunity
ü Passive—protective material developed in another individual’s immune system and given to previously nonimmune
individual
• Artificial immunity
exposure to causative agent is deliberate
ü Active—active disease produces immunity
ü Passive—immunity passes from mother to foetus through placenta or from mother to child through mother’s milk
