The immune response of the body that reacts to specific foreign cells identified by the antigens on their surface.
Proteins that have a carbohydrate chain attached to them. The carbohydrate chain sticks out of the outside of the cell and is part of the cell recognition system.
The tubes through which blood is carried around the body eg arteries, veins and capillaries
An area of the brain which regulates hormone release, temperature control, hunger, thirst and sleep.
Energy producing organic compounds which are made of carbon, hydrogen and oxygen. Examples of food containing carbohydrate are rice, pasta, bread and potatoes
Lipids that have a carbohydrate chain attached to them. The carbohydrate chain is attached to the outside of the cell and is part of the cell recognition system.
Chemicals released from cells which set up an inflammatory response
The process of replacing a damaged or diseased organ with a healthy organ from a dead or living donor.
Proteins produced by the plasma cells (B cells, a type of white blood cell) of the immune system in response to a specific antigen..
Cells that release histamines as part of the inflammatory response
White blood cells
Phagocytes are the white blood cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells
Very small blood vessel with walls made of a single layer of epithelial cells. Exchange of materials, such as nutrients, oxygen and carbon dioxide, takes place between the blood and the cells of the body across the capillary walls.
The vesicle in a phagocyte that surrounds ingested material such as a pathogen and fuses with a lysosome to provide the enzymes needed to digest it.
The process by which the folding of the long chains of amino acids making up a protein is damaged and destroyed by heat, pH changes etc, changing the structure and function of the entire molecule.
Small sac that stores or transports substances inside a cell
A group of cells in an organism that are specialised to work together to carry out a particular function.
A mass of abnormal cells which keep multiplying in an uncontrolled way.
The yellow liquid which supports all the cells of the blood and transports dissolved substances around the body
Swelling caused by fluid retention
A structure with a particular function which is made up of different tissues.
Every day you meet millions of pathogens in your daily life – why aren’t you constantly ill? The human body has many different defence mechanisms against pathogens. They all depend on recognising foreign material and destroying or, at the very least, inactivating the pathogen.
The human body has a number of adaptations that either prevent the easy entry of pathogens into the body or destroy pathogens as soon as they get inside, before they can cause an infection. For example:
The clotting and healing process that protects the body from the entry of pathogens through an open wound.
The cell surface membranes are the site of cell identification systems. There are glycoproteins and glycolipids (proteins and lipids with short carbohydrate sections attached to the molecules) and these, along with some membrane proteins, act as antigens identifying one cell to other cells. For example this system enables the cells of the immune system to identify pathogens, cells from other organisms of the same species (eg after an organ transplant), abnormal body cells (eg cancer cells) and toxins produced by pathogens. It is also key in the non-specific responses of the body to invading pathogens.
Non-specific responses to infection are usually triggered either by body cells breaking down and releasing chemicals, or by pathogens that have been labelled by the specific immune system. Many of the non-specific responses depend on the many different types of leucocytes (white blood cells). The different cells can be recognised both by their appearance and their functions.
The leucocytes or white blood cells play key roles in both the non-specific responses to infection and the specific immune system