StemCell Therapy

What is the immune system?

We are surrounded by millions of bacteria, viruses and other microbes (germs) that have the potential to enter our bodies and cause harm. The immune system is the body's defence against pathogens (disease-causing microbes). The immune system is made up of non-specialised defences such as skin and the acidic juice produced by your stomach. But it also has some highly specialised defences which give you immunity against (resistance to) particular pathogens. These defences are special white blood cells called lymphocytes. Other types of white blood cells play an important part in defending your body against infection.

The lymphatic system is also part of the immune system. The lymphatic system is made up of a network of vessels (tubes) which carry fluid called lymph. It contains specialised lymph tissue and all of the structures dedicated to the production of lymphocytes.

The immune system is generally divided into two parts. The first part is the defences you are born with. These form what are known as the innate system.

The second part of your immune system, known as immunity, develops as you grow. Your immunity gives you protection against specific pathogens. Not only can this system recognise particular pathogens, it also has a memory of this. This means that if you encounter a certain pathogen twice, your immune system recognises it the second time around. This usually means your body responds quicker to fight off the infection.

The innate system is found in many different places around the body. First line of defence is your skin. Skin forms a waterproof barrier that prevents pathogens from entering the body. Your body cavities, such as the nose and mouth, are lined with mucous membranes. Mucous membranes produce sticky mucus which can trap bacteria and other pathogens. Other fluids produced by the body help to protect your internal layers from invasion by pathogens. Gastric juice produced by the stomach has high acidity which helps to kill off many of the bacteria in food. Saliva washes pathogens off your teeth and helps to reduce the amount of bacteria and other pathogens in your mouth.

If bacteria or other pathogens manage to get through these initial defences, they encounter a second line of defence. Most of these defences are present in your blood, either as specialised white blood cells or as chemicals released by your cells and tissues.

The second part of your immune system, the part that gives you immunity, involves the activation of lymphocytes. This will be described later on. Lymphocytes are found in your blood and also in specialised lymph tissue such as lymph nodes, the spleen and the thymus.

The first line of defence is your body's skin and mucous membranes, as mentioned above.

If pathogens manage to get through these barriers, they encounter special white blood cells present in your bloodstream. There are different types of white cells, called neutrophils (polymorphs), lymphocytes, eosinophils, monocytes, and basophils.

See original here:
The Immune System | Health | Patient.co.uk

This entry was posted on June 8, 2015 at 3:49 pm and is filed under Immune System. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |