Cells-immune Responses Flashcards
(20 cards)
Give three physical barriers to infection.
- Skin
- Stomach acid ( kills bacteria)
- Gut and skin flora ( natural bacteria that compete with pathogens for food and space.
Name the non-specific immune responses.
- Inflammation
- Lysozyme action
- Interferon
- Phagocytosis
What is the process of inflammation?
Histamines released by damaged white tissues cause vasodilation, which increases the flow of blood to the affected area and the permeability. As a result, antibodies, white blood cells, and plasma leak into the infected tissue and destroy the pathogen.
What are lysozymes?
Enzymes found in secretions such as tears and mucus, which kill bacterial cells by damaging their cell wall.
What is the purpose of interferon?
Prevents viruses from spreading to neighbouring cells by disrupting their protein synthesis.
What is the process of phagocytosis?
- Chemicals released by pathogens attract phagocytes.
- The phagocyte attaches to the pathogen by binding to its antigens.
- The phagocyte engulfs the pathogen forming a phagosome.
- Lysosomes migrate towards the phasosome.
- Lysozymes/ hydrolytic enzymes hydrolyse the pathogen.
- The soluble products are absorbed, and the insoluble products are presented.
Where do B cells mature?
In the bone marrow.
Where are T cells produced and where do they mature?
Produced in the bone marrow and mature in the thymus gland.
What are memory cells?
Cells that replicate themselves when exposed to an invading pathogen leading to a faster response if re-infected.
What are B-effector and plasma cells?
Antibody producing cells
What is the role of the T helper cells?
Stimulate B cells and T killer cells to divide.
What is the cell mediated response?
Receptors on the T cells will bind onto the antigens on the antigen-presenting cells and cause the T cells to rapidly divide by mitosis. These cloned T cells can then differentiate into different specialised T cells.
What can the T cells specialise into in the cell mediated response?
- Memory T cells
- Cytotoxic T cells
- Helper T cells
What is the function of memory T cells?
Enable a rapid response to reinfection by the same pathogen.
What is the function of cytotoxic T cells?
They kill abnormal cells and infected body cells. They release a chemical called perforin which creates pores in the cell membrane. This allows substances to move into the cell and causes cell death.
What is the function of helper T cells?
Stimulates B cells to divide and secrete antibodies.
What is the humoral response?
- The surface antigens of the invading pathogens are taken up by the B cells.
- The B cells process the antigens and present them on their surface.
- T helper cells attach to the processed antigens and B cells thereby actovating them.
- The B cells divide by mitosis to produce plasma cells.
- The cloned plasma cells produce antibodies that fit the antigens on the pathogens surface.
- The antigens attach to the pathogens and destroy them.
- Some B cells develop inot memory cells
What is the structure of an antibody?
They are made of four polypeptide chains forming a Y shaped structure. They are only complementary to a single antigen.
How do antibodies function?
Form antigen-antibody complexes which serve as markers for phagocytes to destroy attached groups.
They can also clump cells together so they are easier for phagocytes to find in a process called agglutination.
