1. The Lymphatic and Immune Systems13
The Lymphatic and Immune Systems

2. Learning Outcomes
Animal Organ-System and Its Functions: The ENDOCRINE System - STEM_BIO11/12- IVa-h-1
Give the functions of the LYMPHATIC organ-system
Identify the structures and functions of the LYMPHATIC organs
Evaluate the process of IMMUNITY, INFECTIONS, PATHOGEN & ANTIGEN
Describe the Pathophysiology of the LYMPHATIC System

3. (15 mins) Film Viewing
Buzz Session 1. What is the importance of the Lymphatic System? 2. What is it made of? Structures and parts/functions? 3. What are Immunity, Antibody and Antigen in the Body and how does it work
4. What are disorders of the Lymphatic system System? Describe.

4. Introduction Immune system Lymphatic system Protects the body against
Bacteria
Viruses
Fungi
Toxins
Parasites
Cancer
Lymphatic system
Works with immune system to remove disease-causing agents
Organs
Thymus
Spleen
Lymph nodes

5. The Lymphatic System Network of connecting vessels
Collects fluid (lymph) between cells and returns it to bloodstream
Picks up lipids from digestive organs and transports them to bloodstream
Functions to defend the body against pathogens

6. Lymphatic Pathways Lymphatic capillaries Lymphatic vessels
Extend into interstitial spaces
Permeable, thin walls pick up fluid, now lymph
Delivers lymph to lymphatic vessels
Lymphatic vessels
Deliver lymph to lymph nodes
Cells in nodes can remove pathogens from lymph and start an immune response
Leaves nodes through efferent lymphatic vessels
Lymph System

7. Lymphatic Pathways (cont.)
Lymphatic trunks
Receive lymph from efferent lymphatic vessels
Deliver it to
Lymphatic collecting ducts
Thoracic duct
Left side of head and neck, left arm, left side of thorax, entire abdominopelvic area, and both legs
Right lymphatic duct
Right side of head and neck, right arm, and right side of chest
Lymph System

8. Tissue Fluid and Lymph Interstitial fluid
Fluid in spaces between cells that has leaked from blood capillaries and has not been picked up by body cells
High in nutrients, oxygen, and small proteins
Becomes lymph
Pushed through lymphatic vessels by squeezing action of neighboring skeletal muscles and breathing movement

9. Back

10. Lymph Nodes Small, glandular structures
Located along paths of larger lymphatic vessels
Afferent lymphatic vessels – Lymph to node
Efferent lymphatic vessels – Lymph from node

11. Lymph Nodes (cont.) More lymph enters than can leave at one time
Cells in nodes
Macrophages – digest unwanted pathogens
Lymphocytes – start an immune response against pathogen
Nodes can generate some lymphocytes

12. The Thymus and Spleen Thymus Soft, bi-lobed organ
Located just above the heart in the mediastinum
Large in children, shrinks as we age
Functions
Same as lymph nodes
Also produces lymphocytes
Produces thymosin – stimulates production of lymphocytes

13. The Thymus and Spleen (cont.)
Largest lymphatic organ
Located in the upper left quadrant of abdominal cavity
Functions
Filters blood similarly to lymph nodes
Removes worn-out red cells
If removed (splenectomy), liver takes over most of its function

14. 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.
Correct!

15. Defenses Against Disease
Infection
The presence of a pathogen in or on the body
Pathogen
A disease-causing agent
Innate immunity
Nonspecific defenses to protect against pathogens
Nonspecific defenses
Species resistance
Mechanical barriers
Chemical barriers
Phagocytosis
Fever
Inflammation

16. Specific Defenses Against Disease
Immunities
Protect against very specific pathogens
Antigens
Foreign substances in the body
Haptens
Foreign substances too small to start an immune response by themselves
Other substances
Proteins – antibodies and complements
WBCs – lymphocytes and macrophages
Lymph system
Cytokines – assist in immune response regulation
Monokines – increase B cell production and stimulate WBC production

17. Defenses Against Disease (cont.)
Two major types of lymphocytes
Diagram
B Cells and T Cells
Recognize antigens in the body
B cells
Respond to antigens by becoming plasma cells
Plasma cells make antibodies
Memory B cells produce stronger response with next exposure to antigen
T Cells
Cell-mediated response
Bind to antigens on cells and attack them directly
Secrete lymphokines that increase T cell production and directly kill cells with antigens

18. Defenses Against Disease (cont.)
T cell activation
Begins when macrophage ingests and digests pathogen with antigen on it
Antigens are placed on cell membrane of macrophage
T cell recognizes and binds to antigen and the major histocompatibility complex (MHC) on the surface of the macrophage
Now can divide to form other types of T cells

19. Defenses Against Disease (cont.)
Types
Cytotoxic T cells
Protect body against viruses and cancer cells
Helper T cells
Increase antibody formation, memory cell formation, B cell formation, and phagocytosis
Memory T cells
Remember the pathogen that activated original T cell
Later exposures trigger an immune response more effective than initial response

20. Defenses Against Disease (cont.)
Natural killer (NK) cells
Type of lymphocyte
Primarily target cancer cells
Kill on contact
Do not recognize a specific antigen

21. 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 NK T B
Right on Target!

22. Antibodies Also called immunoglobulins IgA IgD IgE
Prevents pathogens from entering body
IgD
Found on B cell membranes
Thought to control B cell activity
IgE
Found with IgA
Involved in triggering allergic reactions

23. Antibodies (cont.) IgG IgM Recognizes bacteria, viruses, and toxins
Activates complements
IgM
Large and binds to antigens on food, bacteria, or incompatible blood cells
Activates compliments

24. Antibodies (cont.) Actions that occur when antibodies bind to antigens
Allow phagocytes to recognize and destroy antigens
Cause antigens to clump together, causing them to be destroyed by macrophages
Cover the toxic portions of antigens, making them harmless
Activate complement
Group of proteins in serum that attack pathogens by forming holes in them
Attract macrophages to pathogens and can stimulate inflammation

25. 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.
Very Good!

26. Immune Responses and Acquired Immunity
Primary immune response occurs with first exposure to antigen
Slow process
Memory cells are formed
Secondary immune response with next exposure to same antigen
Quick and carried out by memory cells
Usually prevents person from developing disease from the antigen

27. Immune Responses and Acquired Immunity (cont.)
Naturally acquired active immunity
Natural exposure to antigen – having an illness
Makes antibodies and memory cells
Long-lasting
Artificially acquired active immunity
Injected with pathogen – immunizations or vaccines

28. Immune Responses and Acquired Immunity (cont.)
Naturally acquired passive immunity
Acquired from mother
Breast milk
Placenta
Short-lived
Artificially acquired passive immunity
Injected with antibodies (such as antivenom)

29. 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.
ANSWER: Immunization is an artificially acquired immunity because a person develops this immunity by being injected with a pathogen and then making antibodies and memory cells against the pathogen.
Good Answer!

30. Major Immune System Disorders
Cancer
Uncontrolled growth of abnormal cells form malignant tumors
Factors known to cause cancer are called carcinogens
Treatment based on stage
0 – very early; cancer cells localized
I – spread to deeper layers or some in surrounding tissues
II – spread to surrounding tissues but contained in primary site
III – spread beyond primary site into nearby areas
IV – spread to other organs
Recurrent – reappeared after treatment

31. Major Immune System Disorders (cont.)
Allergies
Immune response to an allergen
IgE antibodies bind to allergens and stimulate mast cells to release histamine and heparin, triggering allergic response
Allergy shots
Small amounts of allergen stimulates production of IgG to prevent IgE from binding to antigen
IgG antibodies do not stimulate mast cells, so immune response is not generated

32. Major Immune System Disorders (cont.)
Allergy signs/symptoms
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
Treatment
Antihistamines, decongestants – OTC or prescription
Epinephrine for anaphylaxis – vasoconstriction, increasing BP
Anaphylaxis – life-threatening response

33. Common Immune System Disorders
Autoimmune disease
Body attacks its own antigens
Examples
Scleroderma
Rheumatoid arthritis
Multiple sclerosis
Glomerulonephritis
Crohn’s disease
Diabetes mellitus, type I

34. Common Immune System Disorders (cont.)
Description
AIDS
Development of severe signs and symptoms caused by HIV as it destroys lymphocytes; 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
Lymphedema
Blockage of lymphatic vessels results in tissue swelling that increases over time

35. Common Immune System Disorders (cont.)
Description
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

36. 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
___ Severe tiredness E. Lymphedema
___ Uncontrolled growth of abnormal cells F. Mononucleosis
___ Body attacks its own antigens G. Allergy
ANSWER: G E F B A C D

37. End of Chapter 13
Thought is an infection. In the case of certain thoughts, it becomes an epidemic.
~Wallace Stevens