Transcript The Immune System

The Immune System
Marie Černá
Immune system
• belongs to basic homeostatic
mechanisms of organism
• Its function is maintaining the integrity
of organism by recognition of harmful
from harmless, and by this way it
protects organism against injurious
matter of external and internal origin.
Immune system
• An antigen is any substance:
biological / chemical,
natural / artificial,
self / nonself
• that elicits an immune response.
Organs of immune system
Cellular components
Humoral components
Leucocytes (white cells)
the defense of the organism
4-10 .103 / mm3 = 4-10 .109 / l
size ≥10 µm in diameter
agranulocytes (lymphoid cells) 30%
lymphocytes (upper slide)
monocytes (lower slide)
granulocytes (presence of granules
in the cytoplasm) 70%
granules have a different affinity
towards neutral, acid or basic
stains and give the cytoplasm
different colors.
neutrophils
eosinophils (or acidophils)
basophils
Monocytes
3-8 % of all leukocytes
the biggest leukocytes: 16-20 µm
Their nucleus is a great reniform or
horseshoe-shaped.
The cytoplasm is transparent, but with
an appearance of "ground glass"
Monocytes are the precursors of
macrophages. After attaining
maturity in the bone marrow, enter
the blood circulation where they
stay for 24-36 hours. Then they
migrate into the connective tissue.
Neutrophils
60-70 % of all leukocytes
Their nucleus is divided into 2 - 5 lobes
connected by a fine nuclear strand.
The cytoplasm is transparent because
its granules are small, pink colored.
Neutrophils are very active in
phagocyting bacteria
=> are present in large amount in
the pus of wounds.
Eosinophils
3-5 % of all leukocytes
Their nucleus is bi-lobed (glasseslike shape).
The cytoplasm is full of pinkorange colored granules.
Eosinophils attack parasites and
phagocyte antigen-antibody
complexes.
Lymphocytes
20-40 % of all leukocytes
Their nucleus is round and large
in comparison to the cell and
it occupies most of it.
The cytoplasm is transparent.
Lymphocytes are cells which,
besides being present in the
blood, populate the lymphoid
tissues and organs too, as well
as the lymph circulating in the
lymphatic vessel.
Basophils
0.5-1 % of all leukocytes
Their nucleus is bi- or tri-lobed.
The cytoplasm is very rich in dark
purple colored granules.
Basophils secrete anti-coagulant
and vasodilatory substances
as histamines and serotonin
=> mediate the hypersensitivity
reaction.
Immunity
• Innate immunity
– First line – integrity of the skin and the mucosa
– Second line – nonspecific defense itself
- cellular components
- humoral components
• Acquired immunity
- cellular components
- humoral components
Innate immunity
First line
– integrity of the skin and the mucosa
– defense mechanisms
mechanical (movement of cilia)
chemical (fatty acids, pH 3-5, lysozyme)
microbial (normal microbes)
Innate immunity
Second line – nonspecific defense itself
- cellular components
phagocytic cells
natural killer (NK) cells
- humoral components
complement system
interferons
Acquired immunity
Specific defense only in vertebrates
- cellular components
T - lymphocytes
B - lymphocytes
- humoral components
antibodies produced by B - lymphocytes
Induction of immunological memory
Literature
Biology, eighth edition,
Campbell, Reece
Unit seven: Animal Form and Function
Chapter 43: The Immune System
Pages 930 – 953