Immune System Flashcards
What are the functions of the Immune system?
Offers protection from:
Pathogens
Allergens
Foreign substances
Cancer
What is an antigen?
A protein marker that identifies every substance
Every substance (pee venom, pollen etc) carries a protein called antigen and when we injest it our body doesn’t recognize it and will attack
Antigens in our body recognize (like a name tag) our cells and they “belong” so the immune system should NOT attack
A protein marker that identifies every substance
Every substance (pee venom, pollen etc) carries a protein called antigen and when we injest it our body doesn’t recognize it and will attack
Antigens in our body recognize (like a name tag) our cells and they “belong” so the immune system should NOT attack
What is an allergen?
Antigens that cause the allergic response
Bee venom
Pollen
What are types of Immunity?
Non Specific-defense mechanism ( sneeze, cough, tears)
Inflammation
Inherited
Acquired (chickenpox)
Active (when your immune system becomes activated)
Passive (when you receive antibodies)
What is non specific immunity?
Innate
Does not involve memory or prior exposure
Two lines of defense:
First Line-
mechanical and chemical barriers
Reflexes (coughing, sneezing)
Second Line:
Phagocytosis
Inflammation
Fever
Interferons
Complement proteins
Natural killer cells
What are some examples of first line of defense? (No immunity involved, it’s your body’s reaction)
Barriers:
Skin
Mucous membranes
Sweat glands
Stomach acid
Cilia
Reflexes:
Sneeze
Cough
Vomiting
Diarrhea
Examples of second line of defense?
Phagocytosis: (a process by which cells engulf and digest foreign particles)
Neutrophils (wbc)
Monocytes (immature macrophages) and macrophages
Inflammation:
Response to any type of irritant (burn, paper cut etc)
Histamine and other chemicals released
Results in redness, swelling and pain
Examples of second line of defense
Fever:
Caused by release of pyrogens
Stimulates phagocytosis and reduces pathogen reproduction
38.5 degrees and higher is when you need to reduce the fever (Tylenol)
Protective proteins and NK cells:
Interferons protect from viruses (like security guards looking for a virus)
Complement proteins result in cell “lysis” (poke holes in cell wall of offending organism, resulting in bacteria leaking out and it can’t reproduce)
What is the Third line of defense?
Specific immunity or response
Have a different immune system from one country to another
Involves memory (if you’ve encountered an antigen once, you’re body will remember and be ready)
Only have antibodies from the specific antigens that you have encountered in your life
B and T lymphocytes made from stem cells in the bone marrow and work together
T cells travel from the marrow to the thymus gland and mature
B start from stem cells and stay there (B cells = bone)
What is inherited immunity?
Inborn
Innate
Species specific
What is Acquired Immunity?
Picked up during lifetime
Natural (from getting a disease like chickenpox or breastfeeding)
Artificial (vaccine or immune globulin) something you have to seek out **
What is natural active immunity?
The immune system has to get to work to form antibodies (chicken pox)
What is natural passive immunity?
Antibodies are given to an individual without their own immune system having to go to work (mom giving antibodies to baby in utero)
What is the Immune Response?
Antigen is a protein found in many surfaces including our own cells
Those that are “ours” are considered safe
Those that are not ours are considered “unsafe”
Those that are foreign prompt the development of T and B cells (antibodies)
What re T cells?
Come from stem cells in bone marrow
Travels to the Thymus (T) for development and maturation
Some move on to live in tissue and others circulate in blood
Attack antigens directly
What are the steps in T cell activation?
T cells are VERY IMPORTANT
Stem cell in bone marrow then travels to thymus, tissue and blood
An antigen is “presented “ to a T cells travel by a macrophage
T cell activation- antigen binds to receptors on both the T helper call and the T cytotoxic cell and is destroyed
Clone production (once activated, T cells produce clones so an “army” is ready next time) ie) memory and specificity)
What are the T cell subtypes?
1) Killer T cell (kills antigens)
2) Helper T cell ( “BOSSo”- stimulates T and B cells)
3) suppressor T cell (inhibits T and B cells)
4) Memory T cell (remembers antigens for the future- has a “camera”)
What are B cells? (2 types)
Come from stem cells in the bone marrow
Mature in bone marrow and then move to lymphatic tissue and circulate
Interact with antigen indirectly (need “permission”)
How does B cell activation work?
Activated B cells produce plasma cells that secrete antibodies
Each B cell interacts with a specific antigen and produces antibodies just for that one antigen (chickenpox and measles have different antibodies)
The B cell is presented with an antigen by a macrophage
B cell and helper T cell activation
Clone production (large quantities produced for later exposure)
What does the lymphatic system do?
Helps maintain homeostasis by eventually returning most of the fluid that has been diverted back into your blood (if it didn’t, your ankles would swell and lugs would fill with fluid and eventually death)
What causes fluid to get drawn back into the capillaries on the venous end in the lymphatic system?
Osmotic pressure
What roles are carried out by the thymus gland?
Provision of a home for T lymphocytes to mature
Secretion of hormones
What are the main functions of the lymphatic system?
Return of tissue fluid to the blood
Defense against disease
Absorption of fats and fat soluble vitamins
What are the components of lymph?
Approximately 15% of tissue fluid becomes lymph
Approximately 3 litres of lymph fluid is formed and drained per day
Lymph is composed of water, electrolytes, waste products and proteins
What happens if the spleen is removed?
An individual is more prone to infection
What is agglutination in the Immune system?
When antigens and antibodies meet and react
What types of immunity protect humans from diseases that is common to other species?
Genetic
Inborn
Innate
What does a neutrophil do?
Engages in phagocytosis
What does a monocyte do?
Matures into a phagocyte once it enters tissue
What does a B cell do?
Secretes antibodies and remembers antigens
What does a T cell do?
Directly kills pathogens and activates and regulates the immune response
What does a macrophage do?
Engages in phagocytosis and presents antigen to lymphocyte
What characteristics are seen with adaptive immunity?
Memory
Specifity
What assists in non specific immune defense?
Interferons
Mucous
Skin
Leukocytes
Natural killer cells
What is the main role of the immune system?
Protection
What does the Cytotoxic T cell do?
Pokes holes in the pathogens cell membrane
What does the Memory T cell do?
Avoids participation in the actual killing of the pathogen
What does the suppressor T cell do?
Inhibits the immune response once the antigen has been destroyed
What does the Helper T cell do?
Also known as the CD4 T cell, it serves as a marker for immune function
Which processes are triggered by the complement cascade of proteins?
Lysis of pathogen cell membrane
Chemotaxis of phagocytes
Increase susceptibility of pathogens to phagocytosis
What does the B cell do upon presentation of an antigen?
Produces clones of plasma cells, some of which become antibodies.
