1. The Immune System: Phagocytosis Pages 101 & 102 of your text book

2. What is the first line of defence to disease?

3. Barriers to entry.

4. How do the following parts of the body prevent the entry of pathogens? Skin Eyes Digestive system Urinary system Respiratory system Reproductive system Use the internet or the textbook to make notes. The online textbook is here: http://www.dynamic- learning-student.co.uk/title_main.aspxhttp://www.dynamic- learning-student.co.uk/title_main.aspx

5. What is phagocytosis? Phagocytosis (from Ancient Greek φαγεῖν (phagein), meaning "to devour", κύτος, (kytos), meaning " cell", and -osis, meaning "process") is the cellular process of engulfing solid particles by the cell membrane to form an internal phagosome by phagocytes. It can be used by the immune system as a non- specific second line of defence against invading pathogens.

6. Phagocytosis Either draw the diagram above or delete this text box and print the slide. Use the information on the next slide to make notes on the process of phagocytosis.

7. 7 Pathogen recognised as foreign – pathogen is antigenic; chemotaxis Pathogen attached to phagocyte by antibody and surface receptors Engulfed by phagocyte by endocytosis – invagination of plasma cell membrane to form a phagosome (a membrane bound vesicle containing the pathogen) Lysosomes (containing lysins & hydrolytic enzymes) fuse to phagosome Release of H 2 O 2, HCl, free radicals into phagosome Digest pathogen – harmless products removed (egested / excreted) or used by phagocyte Phagocyte also displays antigenic components on external surface of plasma cell membrane (antigen presentation) to start immune response Phagocytosis flow chart Phagocytes – originate from bone marrow / foetal liver You may need to do some research to help you understand the information above.

8. To Do: 1.Read pages 101 & 102 of the textbook.textbook 2.Make notes on how histamines enable phagocytes to perform their function. 3.If you have time left, read up on B and T cells (pages 103 – 105). We won’t necessarily cover this again, so make sure you do the work properly! Come to Biology clinic if you have any questions.