2. Chapter 23 Immune System Section 1: Infectious Diseases
Section 2: The Immune System
Section 3: Noninfectious Disorders

3. Pathogens Cause Infectious Disease
Chapter 23
Immune System
23.1 Infectious Diseases
Pathogens Cause Infectious Disease
An infectious disease is a disease that is caused when a pathogen is passed from one organism to another.
Pathogens are the cause of infectious disease.
Bacteria
Fungi
Viruses
Parasites
Protozoans

4. Chapter 23
Immune System
23.1 Infectious Diseases
Koch’s Postulates

5. A disease reservoir is a source of the pathogen in the environment.
Chapter 23
Immune System
23.1 Infectious Diseases
Spread of Disease
A disease reservoir is a source of the pathogen in the environment.
Reservoirs might be animals, people, or inanimate objects, such as soil.

6. Humans are the main reservoir for pathogens that affect humans.
Chapter 23
Immune System
23.1 Infectious Diseases
Human Reservoirs
Humans are the main reservoir for pathogens that affect humans.
An individual that is symptom-free but capable of passing the pathogen is called a carrier.

7. Chapter 23
Immune System
23.1 Infectious Diseases
Animal Reservoirs
Other animals also are reservoirs of pathogens that can be passed to humans.
Influenza
Rabies

8. Contaminated water or food
Chapter 23
Immune System
23.1 Infectious Diseases
Other Reservoirs
Soil
Contaminated water or food

9. Transmission of Pathogens
Chapter 23
Immune System
23.1 Infectious Diseases
Transmission of Pathogens
Direct contact
Indirect contact through air
Vectors
Indirect contact by objects

10. The virus damages tissues and even kills some cells.
Chapter 23
Immune System
23.1 Infectious Diseases
Symptoms of Disease
The virus multiplies in the cells and leaves the cells either by exocytosis or by causing the cell to burst.
The virus damages tissues and even kills some cells.
Harmful chemicals or toxins might be produced.

11. As outbreaks of diseases spread, certain patterns are observed.
Chapter 23
Immune System
23.1 Infectious Diseases
Disease Patterns
As outbreaks of diseases spread, certain patterns are observed.
The Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) monitor disease patterns to help control the spread of diseases.

12. Treating and Fighting Diseases
Chapter 23
Immune System
23.1 Infectious Diseases
Treating and Fighting Diseases
An antibiotic is a substance that can kill or inhibit the growth of other bacteria.
Penicillium
Erythromycin

13. Helps to prevent disease
Chapter 23
Immune System
23.2 The Immune System
Nonspecific Immunity
The body has a number of defenses in the immune system that fight off pathogens.
These defenses are nonspecific because they are not aimed at a specific pathogen.
Helps to prevent disease
Helps to slow the progression of the disease

14. Dead skin cells help protect against invasion by microorganisms.
Chapter 23
Immune System
23.2 The Immune System
Skin Barrier
Dead skin cells help protect against invasion by microorganisms.
Bacteria that live symbiotically on the skin digest skin oils to produce acids that inhibit many pathogens.

15. Saliva, tears, and nasal secretions contain the enzyme lysozyme.
Chapter 23
Immune System
23.2 The Immune System
Chemical Barriers
Saliva, tears, and nasal secretions contain the enzyme lysozyme.
Lysozyme breaks down bacterial cell walls, which kills pathogens.
Mucus acts as a protective barrier, blocking bacteria from sticking to the inner epithelial cells.

16. Nonspecific Responses to Invasion
Chapter 23
Immune System
23.2 The Immune System
Nonspecific Responses to Invasion
The body has nonspecific immune responses to pathogens that get beyond its barriers.
Cellular defense
Interferon
Inflammatory response

17. Chapter 23
Immune System
23.2 The Immune System
Cellular Defense
Phagocytosis is the process by which phagocytic cells surround and internalize the foreign microorganisms.
The phagocytes release digestive enzymes and other harmful chemicals from their lysosomes, destroying the microorganism.

19. Virus-infected cells secrete a protein called interferon.
Chapter 23
Immune System
23.2 The Immune System
Interferon
Virus-infected cells secrete a protein called interferon.
Interferon binds to neighboring cells and stimulates these cells to produce antiviral proteins which can prevent viral replication in these cells.

20. Inflammatory Response
Chapter 23
Immune System
23.2 The Immune System
Inflammatory Response
Increased blood flow to the infected area makes blood vessels more permeable to allow white blood cells to escape into the infected area.

21. Specific Immunity Lymphatic system
Chapter 23
Immune System
23.2 The Immune System
Specific Immunity
Lymphatic system
Organs and cells that filter lymph and blood and destroy foreign microorganisms

22. Lymphatic Organs Lymphatic tissue Lymphocytes
Chapter 23
Immune System
23.2 The Immune System
Lymphatic Organs
Lymphatic tissue
Lymphocytes
Lymphocytes are a type of white blood cell that is produced in red bone marrow.

23. These lymphatic organs include
Chapter 23
Immune System
23.2 The Immune System
These lymphatic organs include
Lymph nodes
Tonsils
Spleen
Thymus gland
Diffused lymphatic tissue found in mucous membranes of the intestinal, respiratory, urinary, and genital tracts

24. 3rd line: Lymphocytes Specific defense responds to specific invaders
B cell
Specific defense
responds to specific invaders
recognizes specific foreign antigens
white blood cells
B cells & antibodies
T cells

25. B cells & Antibodies B cells Plasma B cells B. Memory B cells
white blood cells that attack roaming invaders
mature in bone marrow
Plasma B cells
make antibodies against invader immediately
B. Memory B cells
remembers invader
can make antibodies quickly the next time
protects you from getting disease more than once

26. Antibodies
Antibody a protein molecule which attaches to the ANTIGEN on a pathogen and then either:
The antibody causes the pathogen to be unable to enter any more body cells
2. The antibody attracts a WBC to engulf the pathogen

28. B cells immune responseY Y
B cells
release antibodies
patrol blood
forever
invader (foreign antigen) Y Y Y Y
“reserves”
memory B cells Y
B cells Y Y
recognition Y Y
10 to 17 days

29. You need trained assassins to kill off these infected cells!
What if the attacker gets past the B cells in the blood & actually infects some of your cells?
You need trained assassins to kill off these infected cells!
Attack of the Killer T cells!

30. T cells T cells mature in thymus Helper T cells B. Killer T cells
sounds the alarm for rest of
immune system
B. Killer T cells
destroys infected body cells
C. Memory T cells
remembers invader & reacts against
it again quickly

31. Thymus

32. Immune response invader skin skin invaders in body invaders in blood
invaders infect cells
macrophages
B cells
helper T cells
T cells
plasma B cells
memory B cells
memory T cells
killer T cells Y
antibodies

33. Exposure to harmless version of germ (pathogen)
Vaccinations
Exposure to harmless version of germ (pathogen)
stimulates immune system to produce antibodies to invader
rapid response if future exposure
Most successful against viral diseases

34. Jonas Salk 1914 – 1995 Developed first vaccine against polio
Poliomyelitis (polio) is caused by a virus that enters the body through the mouth. The virus multiplies in the intestine and invades the nervous system. It can cause total paralysis in a matter of hours.
One in 200 infections leads to irreversible paralysis. Among those paralyzed, 5-10 percent die when their breathing muscles are immobilized.
Polio mainly affects children under age 5.
April 12, 1955

35. Polio epidemics 1994: Americas polio free
1916 The first major polio epidemic strikes in the United States; 27,000 people suffer paralysis and 6,000 die. Increasing numbers of outbreaks occur each year.
1921 Franklin D. Roosevelt is diagnosed with polio.
1928 Iron lungs are introduced to help patients with acute polio breathe.
1932 Franklin D. Roosevelt is elected President of the United States
1949 Dr. John Enders, Dr. Frederick Robbins and Dr. Thomas Weller develop a way to grow poliovirus in tissue culture, a breakthrough that aided in the creation of the polio vaccine. Their work earned the three scientists the Nobel Prize in physiology and medicine in 1954.
1952 The United States reports 57,628 polio cases -- the worst U.S. epidemic on record.
1979 The last U.S. case of polio caused by wild poliovirus is reported.
1988 Worldwide, polio continues to affect some 350,000 people in 125 countries.
1994 The Americas are certified polio-free.
2000 The Western Pacific region is certified polio-free.
2002 Europe is certified polio-free.

36. Protecting you from disease
Vaccinations (Active Immunity)
Advantage
don’t get illness
long term immunity
produce antibodies for life
works against many viruses & bacteria
Disadvantage
not possible against all invaders
Breastfeeding (Passive Immunity)
mother’s milk gives baby antibodies & keeps baby healthy
IMPORTANT PROTECTION
antibodies pass from mother to baby in breast milk

37. Protecting you from disease
Antibiotics = medicine
advantage
kill bacteria that have successfully invaded you
make you well after being sick
disadvantage
use only after sick
only good against bacteria
possible development of resistance by bacteria (if don’t use correctly)
can get sick again

38. Organ Transplants
When a person receives someone else's organ, the organ has foreign antigens on it.
The recipient’s white blood cells will recognize the organ as foreign, and attack it.
So, the recipient has to take immunosuppressant drugs

39. Immune system malfunctions
Auto-immune diseases
immune system attacks own cells
lupus
antibodies attack many different body cells
rheumatoid arthritis
antibodies causing damage to cartilage & bone
diabetes
beta-islet cells of pancreas attacked & destroyed
multiple sclerosis
T cells attack myelin sheath of brain & spinal cord nerves

40. Immune system malfunctions
Allergies
over-reaction to harmless compounds
allergens
proteins on pollen
proteins from dust mites
proteins in animal saliva
body mistakenly thinks they are attackers

41. Diseases of the immune system
HIV: Human Immunodeficiency Virus
infects helper T cells
helper T cells can’t activate rest of immune system
body doesn’t hear the alarm
AIDS: Acquired ImmunoDeficiency Syndrome
infections by opportunistic diseases
death usually from other invading diseases or cancer

42. HIV-AIDS HIV is transmitted by bodily fluid contact HIV causes AIDS
Sexual contact
Blood-to-blood contact
Using unclean needles
HIV causes AIDS
AIDS-
Acquired Immune Deficiency Syndrome