Disease

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Primary Defence

Mucus Membranes - in body openings exposed to the environment, eyes, ears, genitals, anus and nose etc.

The Skin - physical barrier also can be chemical by producing anti-micrbial low pH inhibits growth of pathogens.

Blood clotting - a mesh of protein fibres and platelets plug the open wound and as the scab dries it shrivels closing the wound.

Inflamation - triggered by cell damage helps to isolate pathogen, release of histamines, vascodilation of an area causes increase in tempereature to fight the pathogen.

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Secondary Defence (Non-specific)

Once the pathogen has entered the body. 

Phagocytes engulf and destroy the pathogen by phagocytosis

Neutrophill - multi-lobed nucleus, made in the bone marrow, short-life span, found on lung suface and can move out of capillaries into tissue fluid.

Macrophage - C-shaped mass nucleus, made in bone marrow, long-lived, become antigen-presenting cells to trigger a specific immune response, settle in organs and lymph nodes.

Antigens are chemical markers on the pathogen that the body recognises as foreign. Opsonins (antibodies) produced by the body attach to the antigen which the phagocytes recognise. 

antibodies bind to the surface receptiors on its plasma membrane, pathogen is engulfed by phagocytosis, enzymes digest the pathogen and then products are absorbed.

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Specific Immune Response

Clonal selection is the activation of T and B lympocyte production. 

- Cytokines are homone-based chemicals that stimulate differentiation and control activity of macrophages and T/B cells.

- Monokines are chemicals that attract neutrophills (known also as chemotaxis)

ANTIBODIES aid the specific immune response made by lymphocytes, made of immuneogloblins. Y shaped.

Constant Region - used to help bind antibody bind onto the antigen, consist of both heavy and light polypeptide chain held together by disulfide bonds

Hinge Region - allows flexibility and both variable regions can move freely to bind to more than once antigen (agglutination)

Variable Region - binds to antigen, specific and complamentry 

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T and B lymphocytes

Interleukulins - chemicals used for communication between white blood cells.

Plasma Cell are made from B lymphocytes they manufacture antibodies

Memory Cells long-term immunity from B lymphocytes

T Helper Cells - release cytokines to stimulate B cells to form and stimulate phagocytosis

T Killer Cells kill the infected body cell that is presenting foreign antigens

T Regulator Cells stop the immune resonse once pathogens are killed

T Memory Cells remain in the blood once the immune response is complete to provide a quick secondary response

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Autoimmune disease

When immune response attacks normal body cells.

B and T cells attack own antigens

Arthritis - attack of membrane around joints.

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