The immune system Flashcards
The first line of defence of the immune system consists of skin and mucous membranes. What does the second line of defence of the immune system consist of?
- Antimicrobial substances
- Natural killer cells
- Phagocytes
- Inflammation
- Fever
The 1st line of immune defence has a rapid onset and involves what…?
Also known as?
The skin and mucous membranes (their physical barrier and secretions)
Innate immunity
The 2nd line of immune defence allows the body to defend against specific invading pathogens and involves white blood cells such as…?
Phagocytes and natural killer cells.
(also involved antimicrobial substances, inflammation and fever)
(non-specific immunity)
The 3rd line of defence evokes antibody- and cell-mediated defences. The particular foreign molecules which evoke this immune response are called what?
A second encounter with the same antigen prompts a rapid and stronger defence response due to the presence of WHAT cells from previous encounters?
Antigens
Memory cells
What is the third line of defence also called?
Adaptive or specific immunity
What are phagocytes and what are the two major types?
Specialised white blood cells that undergo phagocytosis.
Neutrophils and macrophages (which develop from monocytes) are the two major types of phagocytes.
Identify the 5 major phases of phagocytosis
- Chemotaxis
- Adherence
- Ingestion
- Digestion
- Killing
What are the 3 major stages of inflammation?
- Vasodilation and increased vascular permeability
- Phagocyte emigration
- tissue repair
What are the two types of lymphocytes that adaptive immunity involves?
- T cells (mature in the thymus)
- B cells (mature in the red bone marrow)
There are two major types of T cells that exit the thymus. What are they?
T helper cells (CD4 T cells)
T cytotoxic cells (CD8 T cells)
Where are T and B cells activated?
Secondary lymphatic organs and tissues (e.g. lymph nodes, spleen and nodules)
B cells are involved in anti-body mediated immunity. What does this mean?
Directed against extracellular pathogens
T cells are involved in cell-mediated immunity. What does this mean?
Directed against intracellular pathogens (also some cancer cells and tissue transplants)
Cells that directly kill target cells by releasing granules of perforin are called…
Natural killer cells
T helper cells, due to a protein on their plasma membrane, are also known as…?
CD4 T cells
Cytotoxic T cells, due to a protein on their plasma membrane, are also known as…?
CD8 T cells
Vasodilation and increased permeability of blood vessels is due to the release of…?
Histamine
Is inflammation a 1st or 2nd line of defence?
2nd