The body’s immune system is the body’s network which works to defend a person against pathogens
such as bacteria, viruses, and fungi. Different organs, such as white blood cells- such as phagocytes
and lymphocytes, antibodies, bone marrow, the spleen, the thymus, the complement, and lymphatic
system are key components in making up the immune system. These components all have different
functions in defending the body and fighting infection.
Antibodies are another very import part of the immune system. Memory cells, for example, are a
type of antibody. Memory cells in your body, T-lymphocytes, and b- lymphocytes) have the function
of recognising and tracking the germs and foreign invaders in the immune system. Once the memory
cells recognise the specific antigens on the pathogen, if the antigen enters a body again, the memory
cells will recognise this antigen and create a more rapid response to fight off the antigen.
The lymphatic system is a system in the body that transport lymphatic fluids, maintains the levels of
fluid in our body and removes any unwanted fluid from the blood vessels. The lymphatic system
works by producing lymphocytes and then releasing them around the body to destroy foreign
invaders and pathogens.
The thymus also helps the body’s defence system. The thymus has the function of creating white
blood cells (T lymphocytes). The thymus produces these white blood cells by producing a hormone
called thymosin, this hormone then helps to make T cells. Once the thymus has created these white
blood cells (T cells), they are distributed around the body and helps fight off infection and diseases.
The spleen has multiple roles in supporting the immune system.
The spleen works with the immune system by filtering out old red blood cells that are no longer
needed and using the old red blood cells to produce white blood cells and platelets which helps the
body fight off an infection.
Bone marrow is a hematopoietic organ that is also part of the body’s defences. The bone marrow
has a very high level of multiple immune cell subsets. Immune cell subsets have functions of
regulating innate and adaptive immune functions. These are important functionalities which are
found in bone marrow, this means that bone marrow can then replace secondary lymphoid tissue
and become the primary immune response instead.
Phagocytes are another part of the immune system. Phagocytes have the function of eliminating any
pathogenic bacteria- such as fungi and bacteria. These phagocytes eliminate pathogenic bacteria by
containing the microorganism before killing them and being processed for antigen presentation. The
complement system is another system, as well as the lymphatic system, that is another part of the
immune system. The functions of the complement system is to enhance the ability of antibodies,
making them able to clear microbes and damaged cells from the immune system. The main function
of the complement system is to attack the cell membrane of any pathogens that enter the body to
destroy them.
, Specific and Non-specific immune system
Immunity is the competence of multi-cellular organisms being able to resist harmful microorganisms.
There are 2 different components of immunity, specific (adaptive) immunity and non-specific
(innate) immunity.
Specific immunity is an immune response found in vertebras which is a specific in responding to a
singular pathogen which is present in the immune system. The response of the immunogen is
specific to the antigen. Specific immunity is not a rapid responding defence mechanism, unlike non-
specific immunity. This is because with specific immunity, the antigens in your immune system need
to be identified before being able to fight off infection and pathogens.
Non- specific immunity is an immune response that responds to multiple antigens, instead of just
one. It is the body’s first immune response. The non-specific immune system fights off multiple
pathogens and is always present at the site of an infection. Once a pathogen enters your body, your
non-specific defence mechanisms can work instantly or take up to a few hours- this is what is classes
as a rapid response. This happens as the cells in the non-specific immune system, also known as the
natural immune system, are triggered by a chemical response once a pathogen enters the body.
The non-specific immune system can use multiple antigens by producing and using white blood cells
and plasma proteins to fight off pathogens. There are several barriers in our body that protect us
and act as a barrier for infection. Phagocytic cells are chemical barriers that make up of macrophages
and neutrophil granulocytes that can engulf bacteria, viruses, and other pathogens before then
destroying them. These cells are found in the bone narrow and are released into your body which
are then released into your blood and tissue.
Physical barriers also protect us from infection. The first physical barrier is the skin. The skin protects
our muscle, flesh and blood from any microorganism that could enter our body and get into our
immune system. The main function of the skin is to protect our body if we are injured to avoid
infection and disease. This is achieved by platelets sticking together with fibrinogen to form fibrin.
Fibrin acts as tiny little threads, which start to form over a cut or would along with plasma. This then
creates a scab which acts as a barrier and protects our body from pathogens entering the body and
avoiding infection of the wound.
Nasal hairs are another form of a physical barrier to avoid pathogens entering our body. Nasal hairs
work to protect us from inhaling harmful debris and bacteria out. They do this because our nose has
tiny hairs called cilia. Cilia work by protecting the nasal passageway by the tiny hairs moving in a
wave-like motion to avoid any big particles, such as dust or pollen, from getting into our respiratory
tract.
Mucus is a chemical barrier to infection. Mucus works by trapping dirt and germs and stopping them
from going to the lungs. This works as you have mucous membranes in your body which produces
sticky mucus, this mucus can then trap any bacteria and other pathogen that are trying to enter your
body.
Sweat is another physical barrier that protects the human body from pathogens. This works as our
sweat glands, after producing sweat, protects skin from pathogen is as sweat spreads highly efficient
antibiotics onto the skin. This antibiotic is a protein called Dermcidin which when released, can fight
and kill bacteria laying on our skin.
Stomach acid protects the body from pathogens as well. This is another chemical barrier to protect
the body from pathogen. Stomach acid works as a chemical protection barrier because the