PHAGOCYTOSIS

Phagocytosis

• 1) A phagocyte moves towards a group of bacteria, and flows around them.

• 2) The phagocyte´s cell membrane fuses together, enclosing bacteria in a vacuole.

• 3) Enzymes are secreted into the vacuole, which digest bacteria.

• 4) Soluble substances diffuse from the vacuole into the phagocyte´s cytoplasm.

Phagocytosis

IMMUNITY

IMMUNITY

IMMUNITY

• ACTIVE: individual makes his/her own antibodies.

• PASSIVE: individual is given ready-made antibodies.

IMMUNITY

• ACTIVE: - NATURAL: . Pathogen infects individual. . Ind. contracts disease, makes

antibodies and is now immune to further infection by the same pathogen.

- ARTIFICIAL: Weakened pathogen (vaccine) Lymphocytes produce antibodies.

IMMUNITY

• PASSIVE: - NATURAL: Mother antibodies cross placenta and are in

breast milk- newborn child temporarily immune to pathogens, e.g. gut infections.

- ARTIFICIAL: . antibodies collected from blood of laboratory animal and stored as serum.

. Adult is now immune to disease. It is used if disease is too fast-acting for the immune system to deal with. It offers a temporary immunity, since the body is not producing any of its own antibodies.