6.3 Flashcards
What is primary defence?
Pores, hair, follicles, sebaceous glands, oils—-> reduce pH, inhibit growth of bacteria
What is the purpose of mucous membranes?
Protect open passages
What happens in blood clotting?
Platelets release thrombin which causes reaction where fibrinogen becomes fibrin and produces a scab
What are phagocytes?
Leukocytes that engulf pathogen and contain enzymes which kill them
What is an antigen?
A foreign substance which triggers the production of antibodies
What is the function of lymphocytes
Produce antibodies specific to pathogens, which attach to antigens and signal phagocytes. Antibodies remembered in memory cells.
How do antibiotics kill bacteria?
Interfere with synthesis of bacterial cell wall, so the plasma membrane is exposed to excessive uptake of water and bursts.
What is HIV?
A tiny virus- 2 strands of RNA, enclosed in a protein coat. Retrovirus, so copies DNA of infected cells by reverse transcription
What are t helper cells?
Recognise antigens and trigger production of antibodies, macrophages and killer T cells
What does HIV do?
Destroys T helper cells, causing a loss of antibodies and thus immunity
