Question

Your task is to discuss how does the immune system utilizes the cardiovascular and lymphatic systems to defend the host against invasion of pathogens. 1. An individual finds himself infected by a previously undiscovered pathogen, Transmissio. A.What is the body’s initial response and long term effects?

Answer 1

The immune system

If pathogens pass the non-specific first line of defence, they will cause an infection. However, the body has a second line of defence to stop or minimise this infection. This is called the immune system, and mainly consists of two types of white blood cell called phagocytes and lymphocytes.

Lymphocytes are another type of white blood cell. They recognise proteins on the surface of pathogens called antigens. Lymphocytes detect that these are foreign, ie not naturally occurring within the body, and produce antibodies. This can take a few days, during which time you may feel ill. The antibodies cause pathogens to stick together and make it easier for phagocytes to engulf them.

Some pathogens produce toxins which make you feel ill. Lymphocytes can also produce antitoxins to neutralise these toxins. Both the antibodies and antitoxins are highly specific to the antigen on the pathogen, therefore the lymphocytes that produce them are called specific.

If your body encounters a particular antigen, your lymphocytes might recognise it. If they do, they clone themselves in order to make enough antibodies to destroy the pathogen. Memory cells are also created which remain in your bloodstream and produce a quick response if the antigen is encountered again. You are then said to be immune.

The best immunity comes from having fought off a disease. However, in some cases such as a serious disease that could prove fatal on first infection, this is not an option. Instead vaccination is used.

White Blood Cells Defend the Body Against Disease

White blood cells, also called leukocytes, defend the body against disease. They normally account for only 1% of circulating blood volume but increase during infection or inflammation. Neutrophils are the most common type, comprising 60% to 70% of all white blood cells. Neutrophils are phagocytes, cells that consume invading pathogens. Lymphocytes, the second most common type of white blood cell, disseminate through the organs and tissues of the lymphatic system. Lymphocytes target specific pathogens as part of the immune response. Other white blood cells include eosinophils, basophils, and monocytes.

Cardiovascular system has white blood cells in it and the lymph system has lymphocytes in it

When a disease 1st expose then it is innate immunity

The innate immune system is one of the two main immunity strategies found in vertebrates (the other being the adaptive immune system). The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the dominant immune system response found in plants, fungi, insects, and primitive multicellular organisms.

The major functions of the vertebrate innate immune system include:

Recruiting immune cells to sites of infection through the production of chemical factors, including specialized chemical mediators called cytokines

Activation of the complement cascade to identify bacteria, activate cells, and promote clearance of antibody complexes or dead cells

Identification and removal of foreign substances present in organs, tissues, blood and lymph, by specialized white blood cells

Activation of the adaptive immune system through a process known as antigen presentation

Acting as a physical and chemical barrier to infectious agents; via physical measures like skin or tree bark and chemical measures like clotting factors in blood or sap from a tree, which are released following a contusion or other injury that breaks through the first-line physical barrier (not to be confused with a second-line physical or chemical barrier, such as the blood-brain barrier, which protects the extremely vital and highly sensitive nervous system from pathogens that have already gained access to the host's body).

In long term it will become acquired immunity