Defence against disease

Learning objectives

Define a pathogen, and describe the primary defences of the skin and of mucous membranes together with blood clotting as a means of sealing wounds and preventing entry

Describe the innate immune response, including phagocytosis by macrophages and neutrophils and the inflammatory response, and explain why it is not specific to a particular pathogen

Explain the adaptive immune response in terms of antigen recognition, the activation and clonal selection of lymphocytes, the production of antibodies by plasma cells and the retention of memory cells

Explain how vaccination produces immunity without disease, describe the role of herd immunity in protecting a population, and use the eradication of smallpox as a case study

Explain how antibiotics act on bacteria but not on viruses, describe the evolution of antibiotic-resistant strains and the measures used to slow it, and describe zoonoses as diseases that cross from other species to humans

Describe the transmission of HIV and its destruction of helper T lymphocytes leading to AIDS