1. The Lymphatic and Immune Systems28
The Lymphatic and Immune Systems

2. Learning Outcomes (cont.)
28.1 Describe the pathways and organs of the lymphatic system.
28.2 Compare the nonspecific and specific body defense mechanisms.
28.3 Explain how antibodies fight infection.

3. Learning Outcomes (cont.)
28.4 Describe the four different types of acquired immunities.
28.5 Describe the causes, signs and symptoms, and treatments of major immune disorders.

4. Introduction Immune system Lymphatic system Protects against
Bacteria
Viruses
Fungi
Toxins
Parasites
Cancer
Lymphatic system
Works with the immune system
Organs
Thymus
Spleen
Lymph nodes
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.

5. The Lymphatic System Network of connecting vessels Functions to
Collect lymph from between cells
Collect lipids from digestive organs
Defend the body against pathogens
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
The Lymphatic System
Collects lymph and return it to the bloodstream
Picks up and transports them to the bloodstream.

6. Lymphatic Pathways Lymphatic capillaries
Collect fluid
Deliver lymph to lymphatic vessels
Lymph vessels – lymph to nodes
Lymph nodes
Remove pathogens
Start immune response
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Lymphatic capillaries
Extend into the interstitial spaces.
Have thin, permeable walls that are designed to pick up fluids.
Once fluid enters the lymphatic capillaries, it is called lymph.
Deliver lymph to lymphatic vessels which delivers it to the lymph nodes.
The cells inside the lymph nodes remove pathogens or start an immune response against the pathogen.
Lymph System

7. Lymphatic Pathways (cont.)
Efferent lymphatic vessels lymphatic trunks
Lymphatic collecting ducts
Thoracic duct
Right lymphatic duct
Empty into blood stream
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Lymph fluid travels away from the lymph nodes through efferent lymphatic vessels.
Efferent lymphatic vessels deliver lymph to lymphatic trunks, and the trunks deliver the lymph to lymphatic collecting ducts.
There are two major lymphatic collecting ducts in the body which empty lymph into the bloodstream, usually near the right and left subclavian veins in the thoracic cavity
The right lymphatic duct
Much smaller than the thoracic duct
Collects all the lymph from the right side of the head and neck, the right arm, and the right side of the chest.
The thoracic duct – collects lymph from the left side of the head and neck, the left arm, the left side of the thorax, the entire abdominopelvic area, and both legs.
Refer to CONNECT to see an animation about Lymph Vessels and Lymph Circulation
Lymph System

8. The Lymphatic System Back
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
The lymphatic capillaries merge to make lymphatic vessels.
Lymphatic vessels eventually merge to make lymphatic trunks, and the trunks merge into lymphatic collecting ducts.
Back

9. The Lymphatic System (cont.)
Area Drained by right lymphatic duct
Right lymphatic duct
Lymph nodes
Lymphatic trunks
Lymphatic vessels
Left internal jugular vein
Thoracic duct
Left subclavian vein
Cisterna chyli
Learning Outcome:
28.2 Define lymph and tell how it is circulated in the body.

10. Tissue Fluid and Lymph Interstitial fluid Lymph moves by
Fluid in spaces between cells
High in nutrients, oxygen, and small proteins
Fluid not picked up by cells  lymph
Lymph moves by
Squeezing action of skeletal muscles
Squeezing action of breathing
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Interstitial fluid
Constantly leaks out of blood capillaries into the spaces between cells
Most is picked up by body cells.
Some persists between cells and becomes lymph.
Lymph vessels contain valves that prevent the backflow.
Edema – tissue swelling caused by lymph that has not been pushed through a lymphatic vessel and leaks back out of the lymphatic capillaries.

11. Lymph Nodes Small, glandular structures
Afferent lymphatic vessels ~ lymph to node
Efferent lymphatic vessels ~ lymph from node
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Lymph nodes are located along the paths of larger lymphatic vessels and are spread throughout the body.
Hilum of the node
Indented
Nerves and blood vessels enter the node through the hilum.
4 or 5 afferent lymphatic vessels carry lymph to a lymph node on the side away from the hilum.
1 or 2 efferent vessels carry lymph out of a node

12. Lymph Nodes (cont.) Lymph pools in the nodes Cells in nodes
Macrophages ~ digest unwanted pathogens
Lymphocytes ~ start an immune response against pathogen
Nodes can generate some lymphocytes
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Because more lymph enters the node than can exit at one time, lymph tends to pool in the node

13. Lymph Nodes (cont.) Back
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Back

14. The Thymus and Spleen Thymus
Soft, bi-lobed organ located in the mediastinum
Functions
Same as lymph nodes
Also produces lymphocytes
Produces thymosin – stimulates production of lymphocytes
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Thymus is larger in children because it assists with production of lymphocytes for the child’s immature immune system.
As immune system becomes fully functional, the thymus becomes almost nonexistent.

15. The Thymus and Spleen (cont.)
Largest lymphatic organ
Upper left quadrant of abdominal cavity
Functions
Filters blood similarly to lymph nodes
Removes worn-out red cells
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Spleen contains blood, macrophages, and lymphocytes.
If the spleen is removed due to injury or disease, the patient’s liver takes over most of the spleen’s functions.

16. Apply Your Knowledge Correct!
What are the lymphatic collecting ducts and what area do they drain?
ANSWER: The collecting ducts are:
Thoracic duct, which drains the left side of the head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs; and the right lymphatic duct, which drains the right side of the head and neck, right arm, and right side of the chest.
Learning Outcome: 28.1 Describe the pathways and organs of the lymphatic system.
Correct!

17. Defenses Against Disease
Infection – presence of a pathogen in or on the body
Pathogen – disease-causing agent
Innate immunity – nonspecific defenses
Immunities – specific defenses
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Nonspecific defenses or innate immunity – mechanisms to protect the body against pathogens in general.
Immunities – protect the body against specific pathogens

18. Non-Specific Defenses
Species resistance
Mechanical barriers
Skin
Mucous membranes
Chemical barriers
Phagocytosis – phagocytes surround and destroy pathogens and unwanted debris
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Species resistance – a species typically gets only diseases that are unique to that species.
Mechanical Barriers
Intact skin – impermeable or resistant to most pathogens.
Intact mucous membranes – generally impermeable, do permit the entry of a few pathogens.
Chemical Barriers – chemicals and enzymes in body fluids destroy pathogens.
Phagocytosis
The process of destroying pathogens by phagocytes
Neutrophils and monocytes are the most active phagocytes in blood.

19. Non-Specific Defenses
Fever
Stimulates removal of iron from blood
Activates phagocytic cells
Inflammation
Redness
Heat
Swelling
Pain
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Fever
Elevated body temperature causes the liver and spleen to remove iron from the bloodstream.
When iron sources are gone, many pathogens are unable to survive.
Activates phagocytic cells in the body to attack pathogens
Inflammation
Occurs in tissue that is injured or infected with a pathogen
Blood vessels in the injured area dilate and become leaky.
More blood enters the area and brings
Phagocytic WBCs to the area
Proteins to replace injured tissues
Clotting factors to stop any bleeding and “wall off” the area so that pathogens cannot spread.
Fluid accumulates in the injured area, which leads to edema and irritates pain receptors.
The four cardinal signs of inflammation are redness, heat, swelling, and pain.

20. Specific Defenses Immunities Antigens
Foreign substances in the body
On the surfaces of pathogens
Haptens – foreign substances too small to start an immune response
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Immunities protect the body against very specific pathogens.
Antigens – the immune system is programmed to recognize antigens in the body.
Haptens
Often join to proteins in the blood, where they are then able to trigger an immune response.
Penicillin is an example of a hapten.

21. Specific Defenses Antibodies – respond to specific antigens
Complements – work with antibodies
WBCs – lymphocytes and macrophages
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Antibodies and complements are the major proteins involved in specific defenses.
Antibodies – proteins produced in response to specific antigens.
Complements – proteins in serum that work with antibodies to eliminate or destroy antigens.
Lymphocytes and macrophages are the major WBCs involved in specific defenses.

22. Specific Defenses Cytokines – assist in immune response regulation
Monokines
Increase B cell production
Stimulate WBC production
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Cytokines – produced by cells of the lymphatic system
Monokines
Cytokines produced by lymphocytes and macrophages
Regulate immune response by
Increasing B cell production
Stimulating WBC production in the red bone marrow

23. Specific Defenses (cont.)
Two major types of lymphocytes
T Cells and B Cells
Diagram
Both recognize antigens in the body
T CELLS
Cell-mediated response
Secrete Lymphokines
B CELLS
Antibody-mediated response
Plasma cells
Memory B cells
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Most of the lymphocytes in blood are T cells. B cells and T cells are also found in lymph nodes, the spleen, the thymus, the lining of digestive organs, and bone marrow.
Both recognize antigens in the body but respond to them in different ways.
T cells – Cell-mediated response
Bind to antigens on cells and attack them directly.
Respond to antigens by secreting lymphokines, which increase T-cell production and directly kill cells that have antigens.
B cells – humoral or antibody-mediated response
Do not attack antigens directly.
Activated when a specific antigen binds to receptors on their surfaces.
Plasma cells make antibodies against the specific antigen which attach to the antigens.
Each group of B cells only recognizes one type of antigen.
Once activated, B cells divide to make plasma cells and memory B cells.
Plasma cells make antibodies that bind to the antigens that activated the B cells.
Memory B cells trigger a faster and stronger immune response the next time the person is exposed to the same antigen.

24. Learning Outcomes: 28.2 Compare the nonspecific and specific body defense mechanisms.
Back

25. Specific Defenses (cont.)
T cell activation
Macrophage ingests and digests a pathogen with antigens on it
Antigens are placed on the macrophage cell membrane next to a major histocompatibility complex (MHC)
T cell binds to the antigen and MHC
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
T cell must be activated before it can respond to an antigen.
Major histocompatibility complex (MHC) – a large protein complex
Every human has a unique MHC – similar to an internal fingerprint.
Every cell in the body has MHC.
T cells cannot be activated without macrophages and MHC proteins.
A T cell that has a receptor for an antigen recognizes and binds to that antigen and the MHC on the surface of the macrophage.
Diagram

26. Specific Defenses (cont.)
Cytotoxic T cells
Memory T cells
Helper T cells
Increase antibody formation
Memory cell formation
B cell formation
Phagocytosis
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
Types of activated T cells
Cytotoxic – protect against viruses and cancer cells
Helper
Memory
Remember the pathogen that activated original T cell
Re-exposure triggers immune response more effective than initial response
Prevents a person from suffering from the same disease twice.

27. Specific Disease (cont.)
Natural killer (NK) cells
Type of lymphocyte
Primarily target cancer cells
Kill on contact
Do not recognize a specific antigen
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms.
NK cells secrete chemicals that create holes in the membranes of harmful cells, causing the cells to burst.

28. Apply Your Knowledge Right on Target!
Identify whether each item refers to T cells, B cells, or NK cells:
___ Primarily target cancer cells
___ Respond to antigens by becoming plasma cells
___ Must be activated to respond to an antigen
___ Bind to antigens on cells and attack them directly
___ Kill on contact
___ Need macrophages and MHC for activation
___ Make antibodies against specific antigen
ANSWER: NK B T T
Learning Outcomes: Compare the nonspecific and specific body defense mechanisms. NK T B
Right on Target!

29. Antibodies Immunoglobulins IgA – prevents pathogens from entering body
IgD – thought to control B cell activity
IgE – involved in triggering allergic reactions
Learning Outcomes: Explain how antibodies fight infection.
IgA – found in secretions of the body like breast milk, sweat, tears, saliva, and mucus.
IgD – found on the cell membranes of B cells.
IgE – found wherever IgA is located.

30. Antibodies (cont.) IgG IgM Recognizes bacteria, viruses, and toxins
Activates complements
IgM
Binds to antigens on food, bacteria, or incompatible blood cells
Activates compliments
Learning Outcomes: Explain how antibodies fight infection.
IgG
Primarily recognizes bacteria, viruses, and toxins.
It can also activate complements.
IgM I
A very large antibody that primarily binds to antigens on food, bacteria, or incompatible blood cells.
It also activates complements

31. Antibodies (cont.) Actions
Allow phagocytes to recognize and destroy antigens
Cause antigens to clump together
Cover the toxic portions of antigens
Activate complements
Learning Outcomes: Explain how antibodies fight infection.
When antibodies bind to antigens, they perform one of the following:
They allow phagocytes to recognize and destroy antigens.
They make antigens clump together, causing them to be destroyed by macrophages. This is how incompatible blood cells are destroyed.
They cover the toxic portions of antigens to make them harmless.
They activate complements.
Complements are proteins that attack pathogens by forming holes in them.
Complement proteins also attract macrophages to pathogens and can stimulate inflammation.

32. Very Good! Apply Your Knowledge
What are the possible actions that occur when antibodies bind to antigens?
ANSWER: Possible actions include:
They allow phagocytes to recognize and destroy antigens.
They make antigens clump together, causing them to be destroyed by macrophages.
They cover the toxic portions of antigens to make them harmless.
They activate complements.
Learning Outcomes: Explain how antibodies fight infection.
Very Good!

33. Immune Responses and Acquired Immunities
Primary immune response
Slow process
Memory cells are formed
Secondary immune response
Quick and carried out by memory cells
Usually prevents person from developing disease from the antigen
Learning Outcome: Describe the four different types of acquired immunities.
A primary immune response
Occurs the first time a person is exposed to an antigen.
Takes several weeks to occur.
A secondary immune response
Occurs the next time a person is exposed to the same antigen.
Very quick
Usually prevents a person from developing a disease from the antigen.
A person is born with very few immunities, but normally develops or acquires them as long as his immune system is healthy.

34. Immune Responses and Acquired Immunities (cont.)
Naturally acquired active immunity
Natural exposure to antigen
Makes antibodies and memory cells
Artificially acquired active immunity
Injected with pathogen
Makes antibodies and memory cells
Learning Outcome: Describe the four different types of acquired immunities.
There are four types of immunities a person can acquire.
Naturally Acquired Active Immunity
Occurs after having an infectious disease, caused by pathogens.
Usually long-lasting.
Artificially Acquired Active Immunity
Occurs after receiving immunizations and vaccines

35. Immune Responses and Acquired Immunities (cont.)
Naturally acquired passive immunity
Acquired from mother
Short-lived
Artificially acquired passive immunity
Injected with antibodies
Learning Outcome: Describe the four different types of acquired immunities.
Naturally Acquired Passive Immunity – antibodies from a mother are passed to her baby through breast milk and across the placenta.
Artificially Acquired Passive Immunity – example: if a person is bitten by a snake, a physician will inject her with antibodies (antivenom) to neutralize the venom.

36. Apply Your Knowledge Good Answer!
After you give an immunization to a 2-year-old, her mother asks you why this will work to prevent her from getting a disease. What would you tell her?
ANSWER: Immunization is an artificially acquired immunity . A person develops this immunity by being injected with a pathogen and then making antibodies and memory cells against the pathogen.
Learning Outcome: Describe the four different types of acquired immunities.
Good Answer!

37. Major Immune System Disorders
Cancer
Uncontrolled growth of abnormal cells
Carcinogen
Signs/symptoms vary
Treatment based on staging
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
Benign growth – abnormal cell growth created by normal cells.
In the United States, most common cancers
Men – prostate, lung, and colon cancer.
Women – breast, lung, and colon cancer.
Lung cancer is the leading killer of all types of cancer for all people.
Carcinogen – a factor that is known to cause the formation of cancer .
The causes of cancer are mostly unknown but certain risk factors include
A suppressed immune system
Radiation
Tobacco
Some viruses.
The treatment of cancer differs depending on the type and stage of cancer.

38. Major Immune System Disorders (cont.)
Stage
Description
Stage 0
Very early cancer. Cancer cells are localized in a few cell layers.
Stage I
Cancer cells have spread to deeper cell layers, or some may have spread to surrounding tissues.
Stage II
Cancer cells have spread to surrounding tissues but are considered contained in the primary cancer site.
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
Refer to Table 28-1 Cancer Staging.
Stage of cancer refers to how large a tumor is and how far cancer cells have spread throughout the body.
Treatment can include:
Surgical removal of the tumor
Chemotherapy,
Radiation therapy,
Newer immune therapies,
Transplants (such as bone marrow)
If not curable, its progression can sometimes be slowed, allowing patients to live additional years.

39. Major Immune System Disorders (cont.)
Stage
Description
Stage III
Cancer cells have spread beyond the primary cancer site to nearby areas.
Stage IV
Cancer cells have spread to other organs of the body.
Recurrent
Cancer cells have reappeared after treatment.
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.

40. Major Immune System Disorders (cont.)
Allergies
Immune responses to an allergen
IgE antibodies
Bind to allergens
Stimulate mast cells
Allergy shots
Anaphylaxis ~ life threatening allergic response
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
An allergy can also be an excessive immune response.
Allergens - substances that trigger allergic responses.
IgE antibodies increase and respond when exposed to a allergen.
The IgE antibodies bind to these allergens
They cause mast cells to release histamine and heparin which trigger allergic reactions.
Allergy shots
Injections of tiny amounts of the allergen.
Cause the body to produce IgG antibodies that will prevent IgE antibodies from binding to the allergen so an immune response is not triggered.
Anaphylaxis
A life-threatening condition
Blood vessels dilate so quickly that blood pressure drops too fast for organs to adjust.
Without treatment, patients may go into anaphylactic shock and die.

41. Major Immune System Disorders (cont.)
Allergies (cont.)
Signs/symptoms are based on where exposure occurs
Treatment
Antihistamines, decongestants
Epinephrine for anaphylaxis
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
Inhaled allergens – runny nose, sneezing, coughing, wheezing
Ingested allergens – nausea, vomiting, diarrhea
Skin allergens – rashes
Allergens in blood – most life-threatening; can affect many organs
Refer to CONNECT to see an animation about Immune Response: Hypersensitivity .

42. Common Diseases and Disorders of the Immune System
Autoimmune disease
Body attacks its own antigens
Examples
Scleroderma
Rheumatoid arthritis
Multiple sclerosis
Glomerulonephritis
Crohn’s disease
Diabetes mellitus, type I
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.

43. Common Diseases and Disorders of the Immune System (cont.)
Description
Acquired immunodeficiency syndrome
(AIDS)
Development of severe signs and symptoms caused by HIV as it destroys lymphocytes (T cells); leaves immune system weakened and susceptible to other diseases
Chronic fatigue syndrome (CFS)
Condition of severe tiredness not relieved by rest and not related to other illnesses
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
Acquired immunodeficiency syndrome (AIDS)
Destroys lymphocytes – particularly T lymphocytes
Because a person may be infected with HIV for years before developing symptoms, it is important for all high-risk individuals to be tested.
No cure for AIDS; treatments delay the progression of the disease
Chronic fatigue syndrome (CFS)
The causes are primarily unknown, although the Epstein-Barr virus (EBV) is suspected as a possible cause.
This condition may also be caused by an autoimmune response.

44. Common Immune System Disorders (cont.)
Description
Lymphedema
Blockage of lymphatic vessels resulting in tissue swelling
Mononucleosis
“Mono”; highly contagious viral infection spread through saliva of infected person
Systemic lupus erythematous (SLE)
Autoimmune disorder; produces antibodies that target own cells and tissues; affects women more often than men
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders.
Lymphedema
Tissue swelling lasts longer than a few days or increases over time.
This condition may be caused by parasitic infections, trauma to the vessels, tumors, radiation therapy, cellulitis, and surgeries such as mastectomies and biopsies in which lymph tissues have been removed.
Mononucleosis
A highly contagious viral infection spread through the saliva
Also spread through coughing and sneezing
Caused by either the Epstein-Barr virus or the cytomegalovirus (CMV).
Systemic lupus erythematosus (SLE)
This disorder may be caused by some drugs or by bacterial infections.
Except for its autoimmune component, its actual cause is unknown.

45. Apply Your Knowledge Excellent! Matching:
___ Immune response to a substance A. CFS
___ Blockage of lymphatic vessels B. SLE
___ “Kissing disease” C. Cancer
___ “Butterfly” rash on face D. Autoimmune disease E. Lymphedema
___ Severe tiredness F. Mononucleosis ___ Uncontrolled growth of G. Allergy abnormal cells
___ Body attacks its own antigens
ANSWER: G E F B
Learning Outcomes: Describe the causes, signs and symptoms, and treatments of major immune disorders. A C D

46. In Summary
28.1 The lymph system is composed of pathways known as lymph vessels. In addition to the lymph vessels, the organs of the lymphatic system include lymph nodes, located throughout the body; the thymus, in the mediastinum; and the spleen, located in the LUQ.
28.2 Nonspecific body defenses include species resistance, mechanical and chemical barriers, phagocytosis, fever, and inflammation.
Specific defenses are immunities or defenses against very specific antigens created by B cells, T cells, and natural killer (NK) cells.

47. In Summary (cont.)
28.3 Antibodies work in the following ways: phagocytosis, antigen clumping, covering (inactivating) toxic portions of antigens, and activating complements. Antibodies are also known as immunoglobulins.
IgA prevents pathogens from entering the body;
IgD controls B cell activity;
IgE works with IgA in triggering allergic reactions;
IgG recognizes bacteria, viruses, and toxins and activates complements; and
IgM binds to antigens on food, bacteria, or incompatible blood cells. IgM also activates complements.

48. In Summary (cont.)
28.4 The four types of immune response are naturally acquired active immunity, such as when someone becomes ill and develops immunity; artificially acquired active immunity, as when an injection is given against a pathogen, preventing illness; naturally acquired passive immunity, which occurs when an infant has its mother’s immunity for a short while after birth and through breast milk; and artificially acquired passive immunity, which occurs after injection of antibodies such as with an antivenom.

49. In Summary (cont.)
28.5 Diseases and disorders of the immune system include HIV infection, AIDS, cancer, and allergies, as well as other autoimmune diseases, in which the body attacks its own antigens.
The signs, symptoms and treatments are as numerous and varied as the diseases.
Some of the more common diseases and disorders are discussed in the Common Diseases and Disorders of the Immune System section near the end of this chapter.

50. End of Chapter 28
Thought is an infection. In the case of certain thoughts, it becomes an epidemic.
~Wallace Stevens