Chapter 5: Cell recognition and the immune system Flashcards
Learn all about the immune system, vaccination and how the body protects itself from pathogens
defence mechanisms -
ESASS
TAMPO
skin - physical barrier airways - mucus scalp - oils such as sebum, antimicrobial eyes - tears stomach - acid
Outline the humoral immune response.
invloves B-cells floating around in the fluids of the body B-cells Unlike T-cells, B-cells do not attack pathogens directly. Instead, they
remain in the lymphoid tissues (spleen, lymph nodes) and produce
antibodies that facilitate in the destruction of the pathogen
Where do B lymphocytes mature?
Hint: starts with a b
B-cells mature in the bone marrow
Where do T lymphocytes mature?
Hint: starts with a t
T-cells mature in the thymus gland
Outline the cell mediated immune response.
- a pathogens infects a host cell or is engulfed by a
- specific helper t cell
- activates t cell to divide form clones
some become memory
some
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What is passive immunity?
…
When foreign antigens are detected by the immune system, an immune response is triggered. Describe how an immune response is triggered.
Phagocytes engulf any pathogens/antigens and are able to activate T-cells. T-cells go on to activate B-cells and B-cells divide into plasma cells which secrete antibodies that are specific to an antigen and help to destroy it.
What is a phagocyte?
A type of white blood cell. It is part of the immune system and its main job is to carry out phagocytosis, that is to engulf and destroy foreign pathogens/viruses/bacteria/microbes and to get rid of waste materials
How do T-cells become activated?
- T-cells bind to the antigens presented on the surface of an AP phagocyte
- T-cells have receptor proteins on their surface complimentary to specific antigens
- binding stimulate T-cells to divide and form clones
- clones differentiate into different types of cells: some become memory cells, killer/cytotoxic T-cells, and memory cells
What are T-cells?
T-lymphocytes are white blood cells that develop in the thymus, and are concerned not only with
cellular immunity but also with the regulation of the humoral response by the B-lymphocytes
What are B-cells?
B-lymphocytes make antibodies in the humoral response to infection, and are found in the lymphoid organs (except thymus)
What is immunity?
Immunity: The ability to be resistant to infection, particularly by poisons, foreign proteins and invading parasites, due to the presence of antibodies and memory cells
What is an antigen?
A substance, that when introduced into the tissues or blood activates the immune system which is induced to form antibodies. The antibodies are specific to the antigen and react with it to make it harmless. Antigens may be
protein, lipoprotein, nucleoprotein, glycoprotein or sometimes large polysaccharides. They may be components of bacteria, viruses, pollen,
egg white, incompatible blood cells or cells from transplanted organs, or abnormal/cancerous body cells. Toxins released by some bacteria and viruses may also act as antigens
What is a macrophage?
A type of phagocyte. (Phagocyte is a generic or broad term for cells that are capable of engulfing small particles)
What do killer/cytotoxic T-cells do?
- Kill abnormal and invaded cells
- by releasing perforin
- a protein that creates holes in the cell surface membrane
- so that cell membrane becomes freely-permeable
- and the cell therefore dies
