Blood 4.2.2.3 pt2

phagocytes response to pathogens

phagocytes detect microorganisms that are foreign to the body. The phagocytes change shape, producing extensions of their cytoplasm called pseudopodia. They then engulf the pathogens and enclose it in a vacuole. It then secrete digestive enzymes held in vesicles into the vacuole which digest the pathogen.

lymphocytes response to pathogens

pathogens have uniquely shaped molecules called antigens on their surface. lymphocytes will detect these and start to produce proteins called antibodies which have specific shape to the antigens. These antibodies attach to the antigens and cause agglutination, when the pathogens clump together which makes it easier for the phagocytes to engulf.

antibodies and antigens shape

antibodies are specific to their antigen

memory cells

when antibodies are produced, memory cells are also produced. These are capable of making the same antibody later on more quickly and in greater numbers. This is why if someone is infected by an antigen again they are able to produce many more antibodies so they recover faster and are less sick in the first place

how does vaccination work

injecting dead or inactive pathogens into the body which still carry antigens so the body can produce memory cells which will help kill the pathogen faster and reduce symptoms if the person ever gets re-infected with the pathogen.

how do platelets work

they enable the blood to clot as they are small cell fragments which clump together and are held by the protein fibrin at the area of the wound.