Immunity

Question 1

Describe the importance of non-specific immunity to include natural baiters and inflammation

Answer 1

Non specific: mechanisms that protect the body against a wide range of dangers, usually present from brith, ‘innate’
1st line non specific: epithelial barriers
- skin and mucous membranes: barriers against pathogens. Nose hair = filter system. Cilia = moves mucus. Epithelial secretions = anti-bacterial, sometimes acidic containing antibodies and enzymes. Sweat= antibacterial, antifungal. One way flow of urine.
2nd line non specific:
-anti-microbial substances
-phagocytosis
-inflammatory response: to isolate, inactive and remove both the causative agent and damaged tissue so that healing can take place

Question 2

Describe the importance of specific immunity

Answer 2

Mechanism directed against one specific invader
The body learns and remembers specific antigens, building an immunological memory
Quicker response time when the antigen is detected again

Question 3

Explain the terms antigen and antibody

Answer 3

Antibodies belong to a group of glycoproteins known as immunoglobulins
Then bind to antigens, labelling them as targets for other defence cells such as cytoxic T-cells and macrophages
Bind to bacterial toxins, neutralising them

Question 4

Briefly describe humoral immunity to include the role of B and T lymphocytes

Answer 4

B cells recognise and bond to antigen particles directly, without having to be presented with them by antigen-presenting cells
B cells make antibodies, some released into the blood stream, but it also displays antibody on cell membrane acting as antigen receptors
T cells then enable B cells to enlarge and proliferate, making 2 distinct types of B cell: memory B cells and plasma cells.
Memory provide long term immunity
Plasma produce antibodies

Question 5

Briefly describe cell-mediated immunity to include the role of T lymphocytes

Answer 5

T cells patrol the body and detect and destroy their antigen should it enter any body tissues
They cannot however detect free antigen directly in body fluids. The T cell must be ‘presented’ with it on another cell. These are called antigen presenting cells (APCs)
Many different cell types present antigens to T cells, and are important in activating adaptive immune system
Macrophages are important APCs. They engulf and digest antigens