The human defence system - Ch 37 Flashcards
Pathogen definition
Organism hat causes disease
Immunity definition
Ability to resist infection
General defence system definition
Acts as a defence to all pathogens
Specific defence system definition
Acts against one type of pathogen. Also called the immune system. Forms antibodies and kills infected cells
Lysozyme meaning
Enzyme in sweat, tears and saliva. Attacks and dissolves cell walls of bacteria
What are the first lines of general defence (4)
- Skin- Physical barrier
- Clotting - Prevent entry
- Lysozyme - Kills bacteria
- Sebaceous glands - produce sebum (oil). Contains bacteria killing chemicals
What are the next first lines of general defence (4)
- Mucus - Body systems lined with sticky music. Pathogens are trapped
- Cilia- Respiratory system lined with tiny hairs. Swoop music up
- Acid - HCL in stomach
- Beneficial bacteria - bacteria in vagina produce lactic acid
What are the 3 second lines or general defence
- Inflammation
- Complement proteins
- Phagocytes
Explain inflammation
Cells that are infected release a chemical reaction that results in blood capillaries opening wider and becoming more porous. This causes localised swelling, redness, heat and pain and brings more WBC to the area. Occurs over the hole body and increases body temp creating fever. Fever interferes with bacteria and virus reproduction
Explain complement proteins
20 proteins found in blood plasma. Activated by infection. Can destroy viruses and other pathogens once activated by bursting them.
Interferons definition
Another set of complement proteins, prevent viral multiplication for example a cold
Explain Phagocytes
Phagocytic white blood cells- macrophages (larger). Chemicals secreted by pathogens attract WBC. WBC’s engulf and destroy pathogens. Found in spleen, lymph nodes, tonsils and appendix. Some move around body fluids
Antigen definition
Substance that causes lymphocytes to produce antibodies
Antibody definition
Protein produced by WBC in response to a specific antigen
Explain monocytes
Develop into WBC called macrophages. These recognise antigens on surface of pathogens. hen macrophage digests a pathogen they display antigen on surface. The antigen then stimulates the production of antibodies. Bot formed in the bone marrow
Explain lymphocytes
Produced in red bone marrow. Found in spleen, thymus, lymph system and blood. Attack body cells displaying antigens on their surface. Others produce antibodies
