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Anatomy
11 Major Systems
1.
2.
3.
4.
5.
6.
7.
8.
9.
Integumentary System
Skeletal System
Muscular System
Nervous System
Circulatory System
Respiratory System
Digestive System
Excretory System
Endocrine System
10. Reproductive System
11. Immune system
• Today you will:
• Compare & contrast non-specific & specific
immunities
• Describe the structure & function of the lymphatic
system
• Understand the importance of B & T cells
• Differentiate between passive and active immunities
• What’s the purpose of receiving a vaccine?
• Why do you think schools require that students be up to date on
their immunizations?
• Aside from vaccines, how might you build immunity to a specific
infectious disease?
• Pathogen: a disease causing agent
• Most pathogens are infectious microbes such as
bacteria or viruses that are capable of causing
disease.
• Other parasitic organisms such as fungi and some
protozoans are also considered pathogens.
• NOT ALL microbes are harmful, the word pathogen
refers specifically only to microbes that cause
disease.
• The body has a number of defenses in the immune
system that fight off pathogens
• Some defenses are considered non-specific
because they are not aimed at a specific pathogen
• Help to prevent a disease
• If disease does occur, this helps to slow the spread of the
disease.
• Dead skin cells help protect against invasion by
microorganisms.
• Some bacteria live on our skin symbiotically. They digest oils
produced by the skin and then secrete a mild acid that inhibits
many pathogens.
• Saliva, tears, and mucus contain lysozyme.
• Lysozyme: an enzyme that breaks down bacterial cell walls
killing the bacteria.
• Mucus acts as a protective barrier by blocking bacteria from
sticking to the epithelial cells (cells under the mucus lining).
• If a pathogen gets through the non-specific barriers there are
3 non-specific responses that may occur.
• Phagocytosis: Process in which a phagocytic cell
surrounds and internalizes a foreign microorganism.
• Once the pathogen is internalized the phagocyte releases
digestive enzymes and other chemicals from their
lysozomes to destroy the pathogen.
bacterium
phagocyte
• Virus infected cells secrete a protein called
interferon.
• Interferon binds to neighboring cells and causes
those cells to produce antiviral proteins so those
cells aren’t infected with the virus.
• Interferon can also allow cells to communicate to the
immune system to eradicate a pathogen or a tumor.
• Increase blood flow to the infected area makes blood vessels
more permeable to allow white blood cells to enter the
infected are.
• Lymphatic system
• Organs and cells that filter lymph fluid and destroy pathogens.
• Lymphocytes: a type of white blood cell (WBC) produced in
the bone marrow
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Lymph nodes
Tonsils
Spleen
Thymus glans
Other tissues in mucous membranes
in the intestinal, respiratory, urinary,
and genital tracts.
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B-Cells
Helper T-Cells
Killer T-Cells
Memory Cells
• Antigen: A substance on a pathogen that causes the
immune system to produce antibodies.
• Antigens have marker molecules (proteins) on their surface that
have unique shapes making them identifiable to other cells.
• Antibody: A substance produced by the immune system
in response to (against) an antigen
• Located in all lymphatic tissues and produce antibodies
• An activated helper T-Cell presents processed antigens (from
a pathogen) to a B-Cell.
• B-Cell: manufactures antibodies to bind the antigen in the
body.
• The antibodies enhance immune system response by binding
to pathogens making them more susceptible to phagocytic
destruction and also speed up inflammation and non-specific
response.
Antibody Receptor
Antigen Markers
• Helper T-Cells bind to & activate cytotoxic T-Cells (Killer TCells) to help fight a pathogen
• Activated Killer T-Cells destroy pathogens and release
chemicals called cytokines. Cytokines help to stimulate the
immune system. Especially good at killing virus infected cells
Pathogen
Killer T-Cell
• Temporary protection produced when antibodies made by
other people or animals are transferred into the body
• Long term immunity that occurs after the immune system has
been exposed to disease and memory cells have been
produced.
• This occurs when the immune system is re-exposed
to a particular antigen.
• Faster response compared to the primary exposure
• B and T-Cell response is greater during a secondary
exposure
• The memory of the antigen lasts longer (more memory cells
produced)
• Memory Cells: Remember antigens of pathogens we
have been exposed to in the past so our body can
quiskly destroy the pathogen if it enters the body
again.