Chapter 13

Anatomy Bowl Prep The Lymphatic and Immune System by Zachary Hale

Know and understand these terms.

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The lymphatic system is our “safety net” also known as our immune system. It is composed of vessels that help maintain fluid balance and lymphoid tissues that help protect the internal environment

Understand how the different regions of the body are drained.  Understand the flow of lymph through lymph nodes  Understand the role of lymph nodes in microbial defense 

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Lymph  Fluid in the tissue spaces that carries protein molecules

and other substances back to the blood 

Lymph Nodes  Bundles of cells along the lymphatic system that: ▪ Filters lymph ▪ Defends the body and houses WBC ▪ Has afferent and efferent vessels that allow lymph to flow in and out in one direction

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Lymphatic Vessels  Permit only one way movement of lymph

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Interstitial fluid  Is the fluid that leaks out of the

capillaries and in between tissues 

Right Lymphatic Duct  Returns lymph to the heart from the

right arm, right upper chest, and right side of the face 

Thoracic Duct  Lymph from ¾ of the body return via

the thoracic duct 

Lacteals 

Absorb fats from the villi of the small intestine and carries it through the lymphatic system

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As lymph flows from its origin in the tissue spaces toward the thoracic or right lymphatic ducts and then into the venous blood it is filtered by moving through lymph nodes

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Lymph nodes are used for:  Biological filtration of the lymph and for defense  Fluid enters through the afferent side and leaves via the efferent side  Macrophages and WBC that reside in the lymph nodes filter and

sample the blood ▪ If a pathogen is found it enables body to respond quickly!

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Know the basic roles in immunity of the different lymphatic organs: Thymus, Tonsils (3 types), Spleen Define and study the difference between:  Nonspecific Immunity  Specific Immunity

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Thymus  Small lymphoid organ located in the mediastinum  Composed of lymphocytes in a unique epithelial meshwork  Is the site for T-cell maturation ▪ A WBC vital for defense ▪ T-cells develop under the influence of the hormone thymosin

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Tonsils  Masses of lymphoid tissue  Are located in a protective ring under the mucous membranes of the

mouth and back of the throat 

Spleen  Largest lymphoid organ  Filters the blood

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Specific immunity  Includes protective mechanisms that confer very specific

protection against certain types of pathogens  Involves memory and the ability to recognize and respond to particularly harmful substances 

Nonspecific immunity  Is maintained by mechanisms that affect any irritant or

abnormal substance that threatens the body  General protection!

Know how these proteins function to defend against invasion: 

Antibodies

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Complement

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Antibody:

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Complement proteins

 Protein compounds that are

 Is the name used to describe

normally present in the body  They bind to antigens (may be foreign proteins, most often molecules on the surface of things invading the body)

14 proteins normally present in an inactive state in the blood  Proteins are activated by exposure of complementbinding sites to antibodies  This results in the formation of a highly specialized antigen-antibody complex that targets foreign cells for destruction

Know the basic function of each of these cell types and where they are formed:

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Phagocytes- cells that use phagocytosis to ingest foreign particles  Neutrophils  Monocytes  Macrophages

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Lymphocytes  T-Lymphocytes ▪ Sensitized T cells- can kill invading cells or recruit macropahges

 B-Lymphocytes ▪ Immature B cells ▪ Activated B cells ▪ Plasma cells – send huge amounts of antibodies into the blood

▪ Memory cells – wait in lymph nodes for second exposure to an antigen

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What is a disease process that attacks the immune system directly and how?

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HIV Is a virus that directly attacks the body The virus invades T-cells  Then uses the T-cell machinery to produce more

copies of the virus  Eventually the T-cell is bombarded with new virus molecules and explodes releasing more virus molecules into the blood