Html code here! Replace this with any non empty text and that's it.

The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism’s own healthy tissue.

In many species, the immune system can be classified into subsystems, such as the innate immune system versus the adaptive immune system, or humoral immunity versus cell-mediated immunity.

In humans, the blood–brain barrier, blood–cerebrospinal fluid barrier, and similar fluid–brain barriers separate the peripheral immune system from the neuroimmune system which protects the brain.

The Lymphatic system consists of bone marrow, spleen, thymus and lymph nodes. Bone marrow produces white blood cells, or leukocytes. The spleen is the largest lymphatic organ in the body contains white blood cells that fight infection or disease.

In this amazing lecture series of videos Mobeen Syed explains the human immune system.