The Body's System of Defenses Against Agents That Cause Disease

Immune System
of the Human’s body

• The body’s system of defenses against agents that cause disease.
Non Specific Immunity
• Non specific Immunity avoid pathogen without differentiate the kind of

pathogen.
• Pathogen include bacteria, viruses, and other harmful substance.
• Non specific Immunity divided into external barriers and internal defenses.
External Barriers
• External barriers include skin and , mucous membranes that protect organ
systems open to the external environment, such as digestive, respiratory,
reproductive, and urinary systems.
mucus membrane
Internal defenses
• Phagocytic cells
Microbe that breach a mammals barriers, such as those that enter through
a cut in the skin, are confronted by internal defenses. These are all classified as white
blood cells. Most, such as abundant neutrophils (phagocytic cells) , macrophages ( large
phagocytic cells that wander through the interestial fluid, “eating ” any bacteria and
virus-infected.
• Natural Killer (NK)
NK cells attack cancer cells and virus-infected by releasing chemicals that

lead to cell death.
• Defensive proteins
Proteins attack microbes directly or impede their reproduction.
• Interferons
Interferons are proteins, produced by virus-infected cell that help to limit

the cell to cell spread of viruses.
• Inflammatory responses
The inflammatory responses helps prevent the spread of infection to

surrounding tissues. Inflammation may be localized or widespread (systemic) .
Sometimes microorganism such as bacteria or protozoans get into the blood or release
toxins that are carried through the body in the blood stream. The body may react with
several inflammatory weapons. For instance, the number of white blood cells circulating
in the blood may increase several fold within just a few hours. Another responses to
systemic infection is fever, an abnormally high body temperature.
Specific Immunity
• Microorganisms that breach nonspecific immunity system are confronted by
specific immunity system.
• These responses include protein’s specific immunity called antibody.
• Antibody produced by Lymphocytes.
The Lymphatic System
The lymphatic system consist of a branching network of vessels, numerous lymph node
(little round organs packed with macrophages , white blood cells and several organs ).
The lymphatic vessels carry a fluid called lymph ( contains less oxygen and fewer
nutrients).
Lymphocytes
• Lymphocytes are white blood cell that spend most of their time in tissue and
organs of the lymphatic system which responsible for adaptive immunity.
• Lymphocytes originate from stem cell in the bone marrow.

• Some immature lymphocytes continue developing in the bone marrow, these
become specialized as B lymphocytes or B cells.
• Other migrate to the thymus, a gland above the heart and specialized as T
lymphocytes or T cells.
• The B cells and T cells of the adaptive immune response together provide a dual
defense.
• The B cells defends primarily against bacteria and viruses present in body fluids.
• T cells attack body cells infected with bacteria or viruses.
• Other T cells function indirectly by promoting phagocytosis by other white blood

cells and by stimulating B cells to produce antibodies.
• T cells play a part in both the cell-mediated and humoral immune responses.
Antibodies
An antibody molecule has two related function in the humoral immune response : to
recognize and bind to a certain antigen and to assist in neutralizing the antigen it
recognizes
Human and other mamals have five major classes of antibodies
Immunoglobulin Properties and function
IgG Main form of antibodies in circulation. Production increased after

immunization. Secrete during secondary response.
igA Found in gastrointestinal , respiratory, and urogenital tract mucosa.

Prevent the colonization by pathogens. Also present in saliva, tears
and milk.
igE Responsible for allergic symptoms in immediate hypersensitivity

reactions. Its interaction with basophils and mastocytes cause
histamin release.
igM Function as antigen receptors on lymphocytes surface prior to

immunization. Secreted during primary response.
igD Function as antigen receptors on lymphocytes surface prior to

immunization.
Innate Immunity
• A set of defenses that are active immediately upon infection and are the same
wheter ar not the pathogen has been encouranted previously.Its include of skin
and mucous membrane.
Acquired Immunity
• A set of defenses that is activated only after exposure to specific pathogens.
• One activated, the adaptive immune response provides a strong defenses

against one infectious agent but not another.
• Acquired immunity involve of B cells and T cells.
• Acquired immunity divide into active immunity and passive immunity.
1. Active immunity (because the person’s own immune system actively produced
antibodies). Its divide into natural active immunity and artificial active
immunity ( Vaccinations/ immunization).
Passive immunity (by receiving premade antibodies).For example, a fetus obtained

antibodies from its mother’s bloodstream , a baby receives antibodies in breast milk
Immunization
• In this procedure , the immun system is confronted with a vaccine composed of a

harmless variant of a disease-causing microbe.
• The kind of immunizations are : DPT ( diptheria-pertusis-measles) , MMR (

measles/mumps, rubella), BCG (Bacillus calmette-Guerin), TT ( Tetanus Toxoid),
polio, and chicken pox.
Disorder of the immune system
• AIDS ( acquired immune deficiency syndrome)
• Autoimmune reactions
• Allergy

The Body's System of Defenses Against Agents That Cause Disease

Uploaded by

Copyright:

Available Formats

The Body's System of Defenses Against Agents That Cause Disease

Uploaded by

Document Information

Original Description:

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

The Body's System of Defenses Against Agents That Cause Disease

Uploaded by

Copyright:

Available Formats

Immune System

of the Human’s body

Non Specific Immunity

• Non specific Immunity avoid pathogen without differentiate the kind of

• Pathogen include bacteria, viruses, and other harmful substance.

• Natural Killer (NK)

NK cells attack cancer cells and virus-infected by releasing chemicals that

Proteins attack microbes directly or impede their reproduction.

Interferons are proteins, produced by virus-infected cell that help to limit

The inflammatory responses helps prevent the spread of infection to

• These responses include protein’s specific immunity called antibody.

• Antibody produced by Lymphocytes.

The Lymphatic System

• Lymphocytes originate from stem cell in the bone marrow.

• T cells attack body cells infected with bacteria or viruses.

• Other T cells function indirectly by promoting phagocytosis by other white blood

Human and other mamals have five major classes of antibodies

Immunoglobulin Properties and function

IgG Main form of antibodies in circulation. Production increased after

igA Found in gastrointestinal , respiratory, and urogenital tract mucosa.

igE Responsible for allergic symptoms in immediate hypersensitivity

igM Function as antigen receptors on lymphocytes surface prior to

igD Function as antigen receptors on lymphocytes surface prior to

• A set of defenses that is activated only after exposure to specific pathogens.

• One activated, the adaptive immune response provides a strong defenses

• Acquired immunity involve of B cells and T cells.

• Acquired immunity divide into active immunity and passive immunity.

Passive immunity (by receiving premade antibodies).For example, a fetus obtained

• In this procedure , the immun system is confronted with a vaccine composed of a

• The kind of immunizations are : DPT ( diptheria-pertusis-measles) , MMR (

Disorder of the immune system

• AIDS ( acquired immune deficiency syndrome)

You might also like