1. The Lymphatic System

2. The Lymphatic System
The body is constantly in contact with bacteria, fungi, and viruses (all considered pathogens)
The body has two defense systems for foreign materials

3. Types of Defense Non-Specific Defense First & Second Line of Defense
Doesn’t care what the pathogen is – your body will be defended!

4. Non-Specific Defense Non-Specific Defense Mechanisms Include…
Skin: mechanical barrier, acidic skin secretions can also defend
Mucous Membranes: Mucus and nasal hairs trap microorganisms; Cilia move mucus out of body; Gastric juice, saliva, and tears have enzymes that destroy microorganisms
Skin and Mucous Membranes are the first line of defense against pathogens
Cellular & Chemical Defense: Second line of defense; includes…

5. Non-Specific Defense Phagocytes:
Cell that engulfs a foreign particle, enclosing it in a vacuole; destroyed with enzymatic contents of lysosomes

6. Non-Specific Defense
Examples of phagocytes include macrophages (in body tissues, developed from monocyte WBC), and neutrophils (WBC)

7. Macrophage engulfing E-Coli

8. Non-Specific Defense Natural Killer Cells:
Defensive cells that can kill cancer cells and virus-infected body cells
Release chemicals to destroy invader’s cell membrane and nucleus

10. Non-Specific Defense Inflammatory Response:
Non-specific response triggered whenever body tissues are injured

13. Non-Specific Defense Benefits of inflammatory response include:
Preventing the spread of damaging agents to nearby tissues
Disposes of cell debris and pathogens
Sets the stage for repair

14. Non-Specific Defense 4 Signs of Inflammatory Response:
Redness – due to dilation of blood vessels in area, bringing more clotting proteins/ oxygen/nutrients to the area
Heat – due to dilation of blood vessels in area, helps increase metabolic rate of cells
Swelling – due to plasma (lymph) leaking from blood stream into tissue spaces
Pain – pain receptors activated by plasma leaking

16. Non-Specific Defense
All of the above symptoms are due to the inflammatory chemicals (including histamine and kinins) that are released when cells are damaged

17. Non-Specific Defense Fever: response to invading pathogens
Hypothalamus will reset internal temperature based on presence of pyrogens (chemicals secreted by WBC exposed to foreign substances)
Fever inhibits the release of iron and zinc from liver and spleen needed by bacteria
Fever also increases the speed of tissue repair, but if fever gets too high, it can screw up enzymes and proteins

18. Specific Defense Specific Defense Third line of defense
AKA immune system
Plans defense based on specific type of pathogen/antigen (The antigen is a marker on the pathogen!)
Must first have an initial exposure before it can protect the body against the pathogen
Involves the Lymph Vessels/Nodes and Lymphoid Organs (Tonsils, Thymus, Spleen, and Peyer’s Patches)

19. Specific Defense
2 Types of Response: Humoral and Cell-Mediated

20. Specific Defense 3 important aspects of immune response:
Antigen specific – recognizes and acts against particular foreign substances
Systemic – not restricted to the initial infection site
Has memory – recognizes and mounts a stronger attack on previously encountered pathogens

21. Specific Defense
Antigens: any substance capable of exciting our immune system and provoking an immune response
A foreign signal on the outside of a pathogen!
Examples of common pathogens/antigens
Foreign proteins (ex: blood typing)
Pollen grains
Microorganisms (bacteria, fungi, virus)
Side Note: Our immune cells do not attack our own proteins, but our cells in another person’s body can trigger an immune response because they are foreign (think: organ transplants, blood donation)

23. Immune System Review Types of cells involved
Lymphocytes (WBC): two types…
B Cells: help with humoral defense, produce antibodies
T Cells: help with cell-mediated defense, do not produce antibodies

24. Specific Defense
Both types of lymphocytes originate from red bone marrow
What determines if it will be a B or T cell is where in the body it becomes immunocompetent (capable of responding to a specific antigen)
T Cells: lymphocytes migrating to thymus
B Cells: lymphocytes develop in bone marrow

26. Specific Defense
Our genes determine what specific foreign substances our immune system will be able to recognize and resist – they only become “activated” once exposed to the antigen

27. FYI: Because of the structure of human DNA (deoxyribonucleic acid; the genetic material determining the makeup of all cells), humans are not subject to certain diseases that dogs and other animals are, and vice-versa. For example, humans cannot contract distemper; however, dogs and cats can. Conversely, humans can suffer from measles; dogs and cats cannot. The genetic makeup of human cells (and of animal and plant cells, also) makes it impossible for certain pathogens to infect and reproduce in those cells.

28. Specific Defense
After becoming immunocompetent, both T and B cells migrate to the lymph nodes and spleen, but can be found throughout lymphatic vessels

29. Specific Defenses Macrophages:
Arise from monocytes (WBC) formed in the bone marrow
Job is to engulf foreign particles (part of non-specific defense) and present fragments of these antigens on their surface (so T Cells can recognize them and become activated, helping out specific defense!)

30. Humoral Defense Making the Antibodies
B Cells with specific receptors bind to a specific antigen
…which causes the B Cell to undergo “clonal selection” – a whole bunch of clones are made!

31. Humoral Defense
Most of the clones will become “plasma cells”, which are responsible for producing specific antibodies!
A few of the clones will become “memory cells”, which will be ready to bind with the antigen if it should come around again

33. Humoral Defense Antibodies
Soluble proteins secreted by B cells (plasma cells)
Carried in blood plasma
Usually has a T or Y shape formed by amino acid chains
Capable of binding specifically to an antigen

34. Humoral Defense
When antibodies attach to antigens, it can have different effects…

35. Humoral Defense
Complement Fixation: antibody will join with a “complement protein” on the invader; which will allow holes on the invader surface; will result in cell lysis (bursting of cell)

36. Humoral Defense
Neutralization: surrounds antigen to mask its effects

37. Humoral Defense
Agglutination: clumping of antigens; will allow macrophages to easily catch and engulf invaders

39. Cell Mediated Defense Begins with macrophages destroying an antigen
Macrophage will then put fragments of the destroyed antigen on the outside
T Cells will recognize the antigen being presented by the macrophage and bind with the antigen (Antigen Presentation)
After binding, T Cell clones form, but different classes of cells are produced

40. Cell Mediated Defense
Cytotoxic T Cell: “killer” cells, specialize in killing virus-infected, cancer, and foreign cells, often by inserting toxic chemicals, causing the pathogen cell to “blow up”
Note: basically does the same thing as a Natural Killer Cell, but does it to a specific pathogen!

41. http://highered. mcgraw-hill

43. Cell Mediated Defense
Helper T Cell: “regulator/conductor” cells, encourages cloning of B cells, stimulates Cytotoxic T Cells to grow and divide, enhances eating capabilities of macrophages

44. Cell Mediated Defense
Supressor T Cell: helps to stop immune response once an antigen has been inactivated or destroyed

45. http://highered. mcgraw-hill

46. Viruses Not considered “living” because has no cytoplasm or organelles
Needs a living host cell to survive
Will take over host cell to replicate
Virus infections cannot be treated with antibiotics
Some can be prevented with vaccines

47. Viruses Common Cold Varicella - Chicken Pox – rarely fatal
Variola – Smallpox – often fatal – but now eliminated thanks to vaccinations!
Influenza – MANY different strains!
Human Papillomavirus – HPV – can lead to warts, cervical cancer, and some other genital cancers
Rotavirus – leading cause of diarrhea among infants and young children

48. Smallpox
Chicken Pox

49. Viruses Mumps – swelling of salivary glands, and testicular swelling
Measles – can lead to diarrhea, pneumonia, encephalitis, and eye infections
Rubella – rash
Poliomyelitis – in less than 1% of polio cases, virus enters the CNS, destroying motor neurons, leading to muscle weakness and paralysis; highly contagious
Rabies – causes encephalitis; extremely fatal
HIV

50. MMR Vaccination protects against all three!
Measles
Mumps
Rubella
MMR Vaccination protects against all three!

52. Vaccination
Administration of antigenic material to produce immunity to a disease
Can be live but weakened, dead, or inactivated form of pathogen (virus or bacteria)
Pathogens are grown in culture and killed/weakened, but surface proteins are intact enough to be recognized
When injected, immune system will evoke a response

53. Bacteria Are considered a “living” prokaryotic cell
Does not need a living host cell to survive
Most (99%) are good, but a few are harmful
Good ones help us with digestion, releasing vitamins, eliminating body toxins, preventing fungal growth

54. Bacteria Harmful bacterial infections can be treated with antibiotics
Some can live harmlessly, but develop into an infection if immune system has had its resistance lowered (ex: AIDS)
A few infections can be prevented with vaccines

55. Bad Bacteria Tuberculosis – affects lungs
Streptococcus – affects throat (pharynx, larynx, tonsils)
Botulism – weakens muscles, prevents breathing
Bubonic Plague – spread by fleas that live on rats; damages lymph notes
Cholera – affects small intestine, causes diarrhea, vomiting, and rapid dehydration

57. Bad Bacteria Salmonella – can cause digestive issues
Escherichia Coli – aka E.Coli – some strains are good, but the bad strains can cause lower digestive issues or UTIs
Syphilis – STD that causes lesions; if left untreated, it can cause issues with the heart and brain
Impetigo – skin infection

58. Bad Bacteria Diphtheria – causes upper respiratory issues
Pertussis – whooping cough
Tetanus – causes muscle spasms
These last three can be quite harmful (even deadly) that we are given the DPT vaccination

59. Antibiotics
A substance or compound that kills or inhibits growth of bacteria
Can either be made synthetically from chemicals or produced by fermenting different fungus molds
Unfortunately, bacteria can mutate to become resistant to antibiotics
EX: penicillin, amoxicillin, tetracycline, sulfa drugs, cefzil

60. Fungus Are considered a “living” eukaryotic cell
Includes molds and yeasts
Some are good, such as fungi used to make antibiotics (penicillin) or baker’s yeast
Infections can spread very easily!

61. Bad Fungi Candida – Yeast Infection Tinea Pedis – Athlete’s Foot
Tinea Cruris – Jock Itch
Tinea Unguium – Nail Fungus

62. Immune System Diseases
Allergies
Abnormally vigorous immune responses
Different types…

63. Immune System Diseases - Allergies
Acute hypersensitivity
Pathogen & resulting antibodies cause release of histamine…
Which causes small blood vessels to become dilated and leaky
Symptoms include runny nose, watery eyes, itching, reddened skin (hives), bronchial constriction (asthma)
Antihistamine drugs can reverse effects

64. Immune System Diseases - Allergies
Anaphylactic Shock
Allergen directly enters the blood and circulates rapidly throughout the body
Examples: Bee stings, spider bites, drug injections
Dilated & leaky blood vessels throughout body can be life-threatening
The drug Epinephrine can reverse effects

65. Immune System Diseases
Immunodeficiencies
Production or function of immune cells is abnormal
May be congenital or acquired
Examples include…

66. Immune System Diseases - Immunodeficiencies
Severe Combined Immunodeficiency Syndrome (SCIDS)
Deficit of both B and T cells
Have no immune response
“Bubble Boy” Disease
Some success with bone marrow transplants

67. For twelve years David Vetter, born with combined immune deficiency, lived inside this plastic bubble at Texas Children's Hospital in Houston, Texas, waiting for a cure to the disease that kept him prisoner.

68. Immune System Diseases - Immunodeficiencies
Acquired Immune Deficiency Syndrome (AIDS)
The virus (Human Immunodeficiency Virus, or HIV) destroys Helper T Cells & Macrophages
Cell-mediated immunity is reduced
Virus then begins to multiply in lymph nodes – which takes longer in some than in others

69. Immune System Diseases - Immunodeficiencies
A patient is diagnosed with AIDS when the lymph nodes are destroyed & symptoms begin
Symptoms include severe weight loss, night sweats, swollen lymph nodes, and increasingly frequent infections (gastrointestinal, pneumonia)
Some of the drugs that are used to help act by inhibiting the enzymes the HIV virus needs in order to multiply, or helps to boost number of Helper T Cells
THERE IS NO CURE OR VACCINE.

70. Immune System Diseases - Immunodeficiencies
Facts:
33.2 million worldwide have AIDS; 2.5 million are children under age 15
1.9 million died of AIDS in 2010; 330,000 were children under age 15
Sub-Sahara Africa contains 68% of the AIDS population
The median survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype

71. Immune System Diseases
Autoimmune Diseases
The immune system does not distinguish between self and non-self
The body produces antibodies and T Cells that attack its own tissues
Examples Include…

72. Immune System Diseases - Autoimmune Diseases
Multiple sclerosis: myelin sheaths in the white matter of brain & spinal cord are destroyed
Type 1 diabetes: destroys pancreatic beta cells that produce insulin
Rheumatoid arthritis: destroys joints
Lupus: affects kidney, heart, lung and skin