Part 1

Learning Intentions Define the immune system Identify different components of the immune system Identify components of the lymphatic system

Homeostasis…

The maintenance of a constant internal environment. e.g. Body temperature Water balance Glucose levels Blood pressure

The Immune System: Is a functional system rather than organ system The immune system is: A network of cells, tissues and organs which work together to defend the body against attacks of foreign invaders The bodies defense where interacting set of specialized cells and proteins designed to identify and destroy foreign invader.

Foreign Invaders?

Foreign Invaders… Primarily microbes - bacteria, parasites and fungi which cause infections. Viruses also cause infections The body provides an ideal living environment to many foreign invaders!! **Why do we get a high temperature when our body is trying to fight a virus?

Self & Non-Self Cells The key to a healthy immune system is its remarkable ability to distinguish between the body’s own cells, recognized as “self,” and foreign cells, or “non-self.” The body’s immune defences normally coexist peacefully with cells that carry distinctive “self” marker molecules. But when immune defenders encounter foreign cells or organisms carrying markers that say “non-self,” they quickly launch an attack.

Antigens… Anything that can trigger this immune response is called an antigen. An antigen is any substance that causes your immune system to produce antibodies (proteins) against it. An antigen may be a foreign substance from the environment such as bacteria, viruses, or pollen or it may be part of a microbe, such as a molecule. Antigens may also be formed within the body.

Autoimmune diseases: In abnormal situations, the immune system can mistake self for non-self and launch an attack against the body’s own cells or tissues. The result is called an autoimmune disease. Includes some forms of arthritis, diabetes, coeliac disease, crohn’s disease etc.

The Immune System:

Lymphatic System: The lymphatic system is a network of organs, lymph nodes, lymph ducts, and lymph vessels that transport lymph from tissues to the bloodstream and back to the heart. The lymphatic system includes the tonsils, adenoids, spleen, thymus and bone marrow. (These produce lymphocytes – White Blood Cells

Lymphatic system:

What is lymph made of?

What is Lymph made of? White blood cells, especially lymphocytes, the cells that attack bacteria in the blood

Lymph Nodes: Lymph nodes are soft, small, round- or bean-shaped structures. Produce immune cells that help the body fight infection. Are a biological filtering system! They filter the lymph fluid and remove foreign material such as bacteria and cancer cells. When bacteria are recognized in the lymph fluid, the lymph nodes produce more infection-fighting white blood cells, which causes the nodes to swell. There are lymph node in the body!!