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The Body’s Defenses The Body’s Defenses - Antibodies
Antibodies and the Lymphatic
and the Lymphatic System
System
Learning Outcomes
C6 describe the components of blood
• explain the roles of antigens and antibodies
C7 describe the inter-relationships of the
structures of the lymphatic system
• describe the functions of the lymphatic system
• q identify and give functions of lymph
capillaries, veins, and nodes
Antibodies and Antigens
• Antigens are foreign
substances that are
recognized by the
immune system
• They are usually proteins
or polysaccharides (such
as those found on cell
membranes or the outer
coat of a virus)
• Antibodies are proteins produced by
lymphocytes, to react with a specific antigen
Antibody Structure
• Contains 4
polypeptide chains
- 2 heavy and 2
light chains
• Has specific sites
that recognizes and
binds to its
particular antigen
(variable region)
• Antibody structure
Antibody production
• B-lymphocyte recognizes a foreign antigen
• B cell is activated to divide rapidly
• B cells in plasma produce and release
antibodies
Antibody Function
• Bind to antigens of invading
cells causing them to clump
together
• Phagocytic w.b.c’s
(macrophages) then
destroy them
• Memory B-cells remain in
the bloodstream providing
lasting immunity – these
will reproduce quickly next
time that specific antigen is
encountered
Antibody video
The Lymphatic System
• A system closely associated with the
circulatory system
• Consists of lymph vessels (veins and
capillaries), lymph nodes, and organs including
the spleen and thymus gland
• A one-way system, from tissues to blood
• Empties into the bloodstream at lymphatic
ducts
Fig. 14.1
Lymph Vessels
• Lymph veins – similar in structures to
circulatory veins; carry fluid from capillaries to
ducts
• Lymph capillaries – found in all tissues, along
with blood capillaries
Lymph Nodes
• Located along lymph vessels
• Contain large numbers of lymphocytes
• Function in fighting infection and antibody
production
Functions of the lymphatic system:
① Immunity / fighting infection
② Absorption of glycerol and fatty acids in the
lacteals
③ Return of excess tissue fluid to the blood
(capillary exchange)