Immune System BIG IDEA: Your body uses fluid, organs, cells and molecules to defend you against disease.

1. How is the flow of lymph through the body different from the flow of blood?

Lymph is carried with blood to the tissues Lymph enters lymphatic capillaries which are different from blood capillaries. These lymph capillaries move lymph to successively larger vessels called lymphatic venules It is carried to lymph nodes Which empty into lymphatic veins Which empty into one of two terminal vessels Right lymphtic duct Thoracic duct Which then empties into the heart 12/5/2018

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What happens in the lymph nodes? Lymph nodes filter out ‘bad’ stuff Lymph nodes have phagocytic cells that destroy bacteria or abnormal cells Lymph enters a node and is ‘percolated’ through the sinus area Lymph enters through the afferent vessel Lymph exits the node through the efferent vessel 12/5/2018

Lymph Nodes Lymph Node magnified Lymph Nodes of the Body 12/5/2018

Lymph Node Structure 12/5/2018

Understanding Define lymph How is a lymph capillary different/same from a blood capillary? What are the names of the 2 large ducts that all lymph empties into? What prevents lymph from flowing backwards? What is the primary function of lymph? What happens in a lymph node? Where are lymph nodes located? 12/5/2018

What other organs are part of the immune system? Thymus Spleen Tonsils 12/5/2018

How does the body defend against infection? 12/5/2018

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If individual A and B had been exposed to a disease in their youth (which means they came down with the symptoms and survived), what type of immunity do they have as adults? A B E F C D G 12/5/2018

Would they pass that immunity to their children? B E F C D G 12/5/2018

If individual F had a measles vaccination, what type of immunity does she have now? B E F C D G 12/5/2018

If baby G is still nursing from his mother, would he have an immunity to measles? If so, what type? If not, can anything be done? A B E F C D G 12/5/2018

The cells and molecules of the immune system Lymphocytes T cells B cells --- antibodies Complement proteins Phagocytes Macrophages Neutrophiles Natural Killer Cells 12/5/2018

Oversimplified: How do these cells work together to provide immunity against disease? 12/5/2018

Vocabulary Cytokines—molecules that signal immune cells to respond Class II MHC molecules (major histocompatibility complex)—make us unique “self” Antigen—foreign material Phagocytosis—engulfing Antigen processing—breaking the antigen into fragments IgM receptors—specific protein involved in making antibodies Memory cells—B cells that “remember” this specific antigen Plasma cells—B cells that create antibodies 12/5/2018

So how do these cells provide immunity from diseases? Humoral immune response Click above or go to: http://bcs.whfreeman.com/thelifewire/content/chp18/1802004.html 12/5/2018

Understanding Foreign invader Macrophage “bumps” into it Macrophage alerts T helper cells T helper cells alert B cells B cells Manufacture antibodies “Remember” this invader in case it invades again 12/5/2018

Does the immune system ever “get it wrong”? YES!! Allergies—inappropriate response to harmless environmental antigens Autoimmunity—inappropriate and excessive response to ‘self’ antigens Isoimmunity—excessive reaction to antigens from a different individual of the same species 12/5/2018