1. PowerPoint Lecture Outlines to accompany
Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter 16
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Chapter 16 Lymphatic System and Immunity
network of vessels that assist in circulating fluids
closely associated with the cardiovascular system
transports excess fluid away from interstitial spaces
transports fluid to the bloodstream
transports fats to bloodstream
help defend the body against diseases

3. Lymphatic Pathways

4. Lymphatic Capillaries
microscopic
closed-ended tubes
in interstitial spaces of most tissues

5. Lymphatic Vessels walls are similar but thinner than those of veins
composed of three layers
endothelial lining (inner)
smooth muscle (middle)
connective tissue (outer)
larger vessels lead to lymph nodes and then to larger lymphatic trunks

6. Collecting Ducts Right lymphatic duct Thoracic duct
drains lymph from the upper
right side of the body
Thoracic duct
drains lymph from the rest of
the body

7. Lymph Trunks & Ducts Vessels unite to form trunks & thoracic ducts
Right side head, arm & chest empty into right lymphatic duct and rest of body empties into thoracic duct
Lymph is dumped directly into left & right subclavian veins

8. Summary of Lymphatic Pathway
Lymphatic vessel to afferent lymphatic to lymph node to efferent lymphatic

9. Tissue Fluid and Lymph Lymph
tissue fluid that has entered a lymphatic capillary
Lymph formation
dependent on tissue fluid formation

10. Tissue Fluid Formation
originates from plasma
contains water and dissolved substances
contains smaller proteins which create colloid osmotic pressure

11. Lymph Formation
increasing hydrostatic pressure within interstitial spaces forces tissue fluid into lymphatic capillaries
resultant fluid is lymph
this process prevents accumulation of excess tissue fluid or edema

12. Lymph Function absorption of dietary fats delivers fats to bloodstream
collection of excess interstitial fluids
delivers excess fluids to bloodstream
delivers foreign particles to lymph nodes

13. Lymphatic Capillaries
Found throughout the body except in avascular tissue (cartilage, epidermis & cornea)
Structure is designed to let tissue fluid in but not out
anchoring filaments keep tube from collapsing under outside pressure
overlapping endothelial cells open when tissue pressure is high (one-way valve)

14. Lymph Movement action of skeletal muscles respiratory movements
smooth muscle in larger lymphatic vessels
valves in lymphatic vessels

15. Major Organs of Lymphatic System

16. Lymph Nodes - Overview
Lymph nodes are encapsulated oval structures located along lymphatic vessels
T cells, macrophages, follicular dendritic cells, and B cells.
Lymph enters nodes through afferent lymphatic vessels, is filtered to remove damaged cells and microorganisms, and exits through efferent lymphatic vessels.
Foreign substances filtered by the lymph nodes are trapped by nodal reticular fibers.
Macrophages then destroy some foreign substances by phagocytosis and lymphocytes bring about the destruction of others by immune responses.
Lymph nodes are the site of proliferation of plasma cells and T cells.
Location of the lymph nodes and the direction of lymph flow is important in the diagnosis and prognosis of the spread of cancer by metastasis

17. Lymph Nodes

18. Locations of Lymph Nodes
cervical region
axillary region
supratrochlear region
inguinal region
pelvic cavity
abdominal cavity
thoracic cavity

19. Functions of Lymph Nodes
filter potentially harmful particles from lymph
immune surveillance by macrophages and lymphocytes
areas of lymphocyte production

20. Lymphatic Nodules
Concentrations of lymphatic tissue not surrounded by a capsule scattered throughout connective tissue of mucous membranes
mucosa-associated lymphoid tissue (MALT)
Peyer’s patches in the ileum of the small intestine
Appendix
Tonsils form ring at top of throat
adenoids (pharyngeal tonsil)
palatine tonsils (on each side wall)
lingual tonsil in the back of the tongue

21. Thymus small in an adult site of T lymphocyte production
secretes thymosins

22. Thymus Gland
Large organ in infants (70 g) but atrophied as adult (3 g)
2 lobed organ located in mediastinum
Capsule & trabeculae divide it into lobules
Each lobule has cortex & medulla
Cortex
tightly packed lymphocytes & macrophages
Medulla
reticular epithelial cells produces thymic hormones
Hassall’s corpuscles

23. Spleen largest lymphatic organ
located in upper left abdominal quadrant
sinuses filled with blood
contains two tissue types
white pulp
lymphocytes
red pulp
red blood cells
macrophages
platelets

24. Spleen
The red pulp consists of venous sinuses filled with blood and splenic cords consisting of RBCs, macrophages, lymphocytes, plasma cells, and granulocytes.
Macrophages remove worn-out or defective RBCs, WBCs, and platelets.
The spleen stores blood platelets in the red pulp.
The red pulp is involved in the production of blood cells during the second trimester of pregnancy.

25. Body Defenses Against Infection
pathogen
disease causing agent
bacteria, viruses, complex microorganisms,
spores of multicellular organisms
innate defenses
general defenses
protects against many pathogens
adaptive defenses
immunity
more specific
memory
carried out by lymphocytes

26. Innate (Nonspecific) Defenses

27. Inflammation Response
KNOW in order!!!

28. Adaptive (Specific) Defenses or Immunity
Two key features
Specificity
Memory

29. Adaptive (Specific) Defenses or Immunity
resistance to particular pathogens or to their toxins or metabolic by-products
based on the ability to distinguish “self” from “non-self”
antigens elicit immune responses

30. Antigens proteins polysaccharides glycoproteins glycolipids
most effective are large and complex
haptens are small molecules that are not antigenic by themselves

31. Lymphocyte Origins
Insert figure 16.16

32. Lymphocyte Functions T cells secrete lymphokines (cytokines)
help activate T cells
cause T cell proliferation
activate cytotoxic T cells
stimulate leukocyte production
stimulate B cells to mature
activate macrophages
secrete toxins that kill cells
secrete growth-inhibiting factors
secrete interferon
cellular immune response

34. T Cells and the Cellular Immune Response
requires antigen-presenting cell
requires MHC antigens
types of T cells
helper T cell (T4)
cytotoxic T cell (T8)
memory T cell

35. Lymphocyte Functions B cells differentiate into plasma cells
produce antibodies
humoral immune response

36. Comparison of T and B Cells
Know!!!

37. Maturation of T and B Cells
T cells mature in thymus
cell-mediated response
killer cells attack antigens
helper cells costimulate T and B cells
effective against fungi, viruses, parasites, cancer, and tissue transplants
B cells in bone marrow
antibody-mediated response
plasma cells form antibodies
effective against bacteria

38. Types of Immune Response
Cell-mediated immunity (CMI) refers to destruction of antigens by T cells.
particularly effective against intracellular pathogens, such as fungi, parasites, and viruses; some cancer cells; and foreign tissue transplants.
CMI always involves cells attacking cells.
Antibody-mediated (humoral) immunity (AMI) refers to destruction of antigens by antibodies.
works mainly against antigens dissolved in body fluids and extracellular pathogens, primarily bacteria, that multiply in body fluids but rarely enter body cells.
Often a pathogen provokes both types of immune response.

39. Antigens Molecules or bits of foreign material (see slide 30 above)
entire microbes, parts of microbes, bacterial toxins, pollen, transplanted organs, incompatible blood cells
Required characteristics to be considered an antigen
immunogenicity = ability to provoke immune response
reactivity = ability to react to cells or antibodies it caused to be formed
Get past the bodies nonspecific defenses
enter the bloodstream to be deposited in spleen
penetrate the skin & end up in lymph nodes
penetrate mucous membrane & lodge in associated lymphoid tissue

40. Major Histocompatibility Complex Antigens
Almost all cells have unique surface markers (1000s molecules)
integral membrane proteins called HLA antigens
MHC-I molecules are built into cell membrane of all cells except red blood cells
Function
if cell is infected with virus, MHC-I contain bits of virus marking cell so T cells recognize the problem
Some cells also display MHC class II antigens.
MHC-II markers seen only on membrane of antigen presenting cells (macrophages, B cells, thymus cells)
if antigen presenting cells (macrophages or B cells) ingest foreign proteins, they will display as part of their MHC-II

41. Pathways of Antigen Processing
B and T cells must recognize a foreign antigen before beginning their immune response
B cells can bind to antigen in extracellular fluid
T cells can only recognize fragments of antigens that have been processed and presented to them as part of a MHC molecule
Helper T cells “see” antigens if part of MHC-II molecules on surface of antigen presenting cell
Cytotoxic T cells “see” antigens if part of MHC-I molecules on surface of body cells

42. Processing of Exogenous Antigens
Cells called antigen-presenting cells (APCs) process exogenous antigens (antigens formed outside the body) and present them together with MHC class II molecules to T cells.
APCs include macrophages, B cells, and dendritic cells.
The presentation of exogenous antigens together with MHC II molecules on antigen presenting cells alerts T cells that “intruders are present”.

43. Processing of Exogenous Antigens
Foreign antigen in body fluid is phagocytized by APC
macrophage, B cell, dendritic cell (Langerhans cell in skin)
Antigen is digested and fragments are bound to MHC-II molecules stuck into antigen presenting cell membrane
APC migrates to lymphatic tissue to find T cells

44. Processing of Endogenous Antigens
Endogenous antigens are synthesized within the body and include viral proteins or proteins produced by cancer cells
Most of the cells of the body can process endogenous antigens
Fragments of endogenous antigen are associated with MHC I molecules inside the cell.
The antigen MHC I complex moves to the cell’s surface where it alerts T cells.

45. T Cell and B Cell Activation

47. B Cell Activation, Stimulation and Proliferation

48. B Cell Proliferation and Differentiation

49. Activation, Proliferation, and Differentiation of T Cells
T cell receptors recognize antigen fragments associated with MHC molecules on the surface of a body cell.
Proliferation of T cells requires costimulation, by cytokines such as interleukin-1 (IL-1) and interleukin-2 (IL-2), or by pairs of plasma membrane molecules, one on the surface of the T cell and a second on the surface of an APC.

50. Activation, Proliferation & Differentiation of Cytotoxic T Cells
Receptor on CD8 cell binds to foreign antigen fragment part of MHC-I
Costimulation from helper T cell
prevents accidental immune response
Proliferates & differentiates into population (clone) of Tc cells and memory Tc cells
Occurs in secondary lymphatic organs such as lymph node

51. Activation, Proliferation & Differentiation of Helper T Cells
Receptor on CD4 cell binds to foreign antigen fragment associated with MHC-II
Costimulation with interleukin
Proliferates & differentiates into population (clone) of TH cells and long-lived memory TH cells

52. Overview of Mature T Cells
Helper T (TH) cells, or T4 cells, display CD4 protein, recognize antigen fragments associated with MHC-II molecules, and secrete several cytokines, most important, interleukin-2, which acts as a costimulator for other helper T cells, cytotoxic T cells, and B cells
Cytotoxic T (TC) cells, or T8 cells, develop from T cells that display CD8 protein and recognize antigen fragments associated with MHC-I molecules.
Memory T cells are programmed to recognize the original invading antigen, allowing initiation of a much swifter reaction should the pathogen invade the body at a later date.

53. Steps in Antibody Production

54. Antibody Structure
Antibodies consist of heavy and light chains and variable and constant portions
Based on chemistry and structure, antibodies are grouped into five principal classes each with specific biological roles (IgG, IgA, IgM, IgD, and IgE).

55. Antibody Molecules

56. Types of Immunoglobulins

57. Antibody Actions

59. Antibody Actions
Neutralization of antigen by blocking effects of toxins or preventing its attachment to body cells
Immobilize bacteria by attacking cilia/flagella
Agglutinate & precipitate antigens by cross-linking them causing clumping & precipitation
Complement activation
Enhancing phagocytosis through precipitation, complement activation or opsonization (coating with special substance)

60. Immune Responses

61. Classifications of Immunity

62. Allergic Reactions
Immune attacks against nonharmful substances that can damage tissues

63. Allergic Reactions Type I immediate-reaction allergy
occurs minutes after contact with allergen
hives
hay fever
asthma
eczema
gastric disturbances
anaphylactic shock

64. Allergic Reactions Type II antibody-dependent cytotoxic reaction
takes 1-3 hours to develop
transfusion reaction
Type III
immune-complex reaction
takes 1-3 hours to develop
antibody complexes cannot be cleared from body
damage of body tissues

65. Allergic Reactions Type IV delayed-reaction allergy
results from repeated exposure to allergen
eruptions and inflammation of the skin
takes about 48 hours to occur

66. Transplantation and Tissue Rejection
Tissue rejection reaction
resembles cellular immune response against antigens
important to match MHC antigens
immunosuppressive drugs used to prevent rejection
Transplanted tissues and organs
cornea
kidney
liver
pancreas
heart
bone marrow
skin

67. Rejection mechanisms
Rejection is an adaptive immune response and is mediated through both T cell mediated and humoral immune (antibodies) mechanisms.
The number of mismatched alleles determines the speed and magnitude of the rejection response.
Different grafts usually have a proclivity to a certain mechanism of rejection.

68. Transplant Rejection Organ/tissue Mechanism
Blood Antibodies, (iso-hemagglutinins) IgM
Kidney Antibodies, CMI
Heart Antibodies, CMI
Skin, CMI
Bone marrow, CMI
Cornea Usually accepted unless vascularized, CMI

69. Autoimmunity
inability to distinguish “self” from “non-self”