Chapter 12- Communicable Dieseas Flashcards
Non specific defences- keeping pathogens out
Skin covers the body and prevents entry of pathogens
Lined with mucous membranes, that seceret sticky mucus
Lysosomes in tears and urine
Blood clotting
If you cut yourself, the skin is breached and pathogens can enter the boy. Blood clots rapidly to seal the wound. When platelets come into contact with collagen in skin or wall of damaged blood vessel, that adhere and begin to secrete several substances.
Inflammatory response
Localised response to pathogens resulting in inflammation at the site of wound
Mast cells are activated in damaged tissue and release chemicals in histamines and cytokines
Histamines make the blood vessels dilate and vessels more leaky
Cytokines attract white blood cells
Non specific defences- getting rid of pathogens
Fevers
Phagocytosis
What are phagocytes?
Specialised white cells that engulf and destroy pathogens. There are two main types of phagocytes- neutrophils and macrophages.
Stages of phagocytosis
- Pathogens produce chemicals that attract phagocytes
- Phagocytes recognise non human proteins on the pathogen
- The phagocyte engulfs the pathogen and encloses it im a vacuole known as a phagosome.
- The phagosome combines with a lysosome to form a phagolysosome
- Enzymes from the lysosome digest and destroy the pathogen
What are opsonins
Chemicals that bind to a pathogen and tag them so they can be more easily recognised
Where do B lymphocytes mature?
Bone marrow
Where do T lymphocytes mature?
Thymus gland
T helper cells
Cell receptors on their cell surface membrane . They produce interleukins which stimulate the activity of B cells, which increases antibody production.
T killer cells
Destroy the pathogen carrying antigen. They produce a chemical called perforin, which kills the pathogen by making holes in its membrane.
T memory cells
These live for a long time and are part of the immunological memory. If they meet a antigen the second time they divide rapidly to form a huge number of T killer cells
T regulator cells
Cells suppress the immune system acting to control and regulate it.
Main type of B lymphocytes
Plasma cells
B effector cells
B memory cells
Plasma cells
These produce antibodies to a particular antigen and release them into the circulation.
B effector cells
Divide to form plasma cell clones
B memory cells
These live for a long time and provide the immunological memory
Humoral immunity
Interleukins produced by activated T helper cells
The activated B cells divide by mitosis to give clones of plasma cells and B memory cells
Cloned plasma cells produce antibodies that disable the antigens , known as primary immune response
Some cloned B cells can develop into b memory cells. Perform part of secondary immune response
Difference between natural and artificial immunity
Natural is where you meet a pathogen for the first time, your immune system is activated and antibodies are formed, which results in the destruction of the antigen
Artificial is where the disease is killed before their immune system makes the antibodies they need.
Artificial passive immunity
Gives temporary immunity is where antibodies are formed in one individual, extracted and then injected into the bloodstream of another individual
Artificial active immunity
The immune system of the body is stimulated to make its own antibodies to a safe form of an antigen, which is injected into the bloodstream
Examples of antibodys actions
Opsonins-tag pathogens for better recognition
Agglutinins-stick pathogens together for better recognition
Antitoxins-neutralize toxins released by pathogens
