Unit 21 : Biomedical Science Techniques. Assignment 2 : The Immune System

The immune system is made up of several types of cells that work together to fight infections. Lymph cells (called lymphocytes) are the main type of cell in the adaptive immune system. There are 2 types of lymph cells: T cells and B cells. When B cells respond to an infection, they change into plasma cells. The plasma cells are found mainly in the bone marrow—the soft, inner part of some bones. The plasma cells

The immune system depends on the body’s structures to help it function. For instance, the skin acts as the “body’s first line of defense.” If a pathogen finds a breach in the skin barrier, it is the circulatory system that must now signal the immune system of the invader. Shortly after, white blood cells will be notified of the infection and will target and destroy the pathogen.

Protection- By white blood cells, antibodies and complement proteins that circulate in blood and defend again foreign microbes and toxins. Also white blood cells clot when body is injured.

The body’s protection against viruses, bacteria and other types of invasions is our immune system (Tortora, 2014).

The human immune system creates a series of responses in the body to defend the body. If a foreign organism, such as a virus or a cold invades your body, it recognizes these foreign organisms, and, in turn, attacks them to get rid of them. One can think of the immune system as an army of many cells which have set up their own bastion in the human body. They have only one job: To defend. The immune system’s cells are various kinds of white blood cells. The human body typically creates about 1000 million white blood cells on a daily basis. A group of these cells, macrophages, establish a patrol of sorts throughout the body killing germs as soon as they enter the body. However, sometimes an infection can cause the macrophages to succumb to it. The body begins to fight back with stronger T- and B-cells.

The organs that make up the lymphatic and immune system are the tonsils, spleen, thymus gland, lymph nodes, and lymphatic vessels. White blood cells (leukocytes), red blood cells (erythrocytes), plasma, and platelets (thrombocytes) make up the blood. Lymphocytes are leukocytes (white blood cells) that help the body fight off diseases. Two types of lymphocytes are B cells and T cells. Lymphocytes recognize antigens, or foreign substances/matter, in the body. Lymphocytes are a classification of agranulocytes, or cells (-cytes) without (a-) granules (granul/o) in the cytoplasm. B cells are created from stem cells, which are located in the bone marrow. B cells respond to antigens by becoming plasma cells. These plasma cells then create antibodies. Memory B cells produce a stronger response with the next exposure to the antigen. B cells fight off infection and bacteria while T cells defend against viruses and cancer cells. A hormone created by the thymus gland called thymosin changes lymphocytes into T cells. The thymus gland is active when you are a child and slowly shrinks, as you get older. T cells bind to the antigens on the cells and directly attack them. T cells secrete lymphokines that increase T cell production and directly kill cells with antigens. There are three types of T cells: cytotoxic T cells, helper T cells, and memory T cells.

Human have different types of blood cells within the body, this includes plasma, platelets, red blood cells and white blood cells.

The immune system is an important and complex part of the human body, guarding it against bacteria

The body fights infection using the immune system, which is made up of millions of cells including T cells and B cells. An important feature of the immune system is that it is much stronger when fighting a disease which it has already fought against before. It has a memory.

Humans such as us alike cannot live in a world without a highly effective defense system that helps us to resist against infections and toxins caused by microorganisms. The immune system is a complex network of consorting cells, tissues and organs that defend the body from pathogens and other harmful substances. This essential complex consists of two subsections : the innate immune system and the adaptive immune system.

Normally the body is protected by the immune system. When the immune system detects an unwelcome visitor such as fungi, bacteria and or viruses

Lymphocytes are a type of white blood cell, which are an important part of the immune system. Lymphocytes can defend the body against infection because they can distinguish the body’s own cells from foreign ones. Once they recognize foreign material in the body, they produce chemicals to destroy that material. Two types of lymphocyte are produced in the bone marrow before birth.

If a pathogen breaches barriers: innate immune response result into an immediate effect of non- specific response. All Innate immune systems derived from plants and animals, when a pathogen evades the innate response, a third layer of protection is possessed by vertebrates in which activation of adaptive immune system takes place. The immune system response adopts itself within an infection and pathogen recognition is improved. As a result of the improved response, its then retains itself when the pathogen is eliminated in form of an immunological memory and allows the adaptive immune system to mount faster and stronger when pathogen is encountered each time.

Another type of cells that protect your body is the Phagocytes. Phagocytes are types of white blood cells that directly ingest the harmful pathogens through the process of phagocytosis. They bind to the pathogen and engulf it. When it engulfs the pathogen, Phagocytes keep the antigen so it can be presented to cells to make antibodies. (Kidshealth.org)

Our immune system is the second most complex system in our body. It is made up of organs, cells and proteins that work together to protect our bodies from harmful bacteria, viruses or other microorganisms that can cause diseases. Usually we don’t notice our immune system defending us against pathogens, but if the pathogen (harmful microorganism) is aggressive or if our body hasn’t ever come into contact with it, we can get sick. The jobs of our immune system are to recognise pathogens, as well as neutralise and remove them from our body. Our immune system also has to fight our own cells if they have changed due to an illness, for example, cancer. (1)