1. The Immune System

2. What is a pathogen?
Disease-causing organisms that can be
present in air, water, food
Pathogens are viruses, bacteria, fungi, protists, and parasites
Microbe= microscopic organism or microorganism such as bacteria
What is a disease?
Any condition that prevents the body from working as it should/No Homeostasis!!
What causes a disease?
Pathogens, cancer, toxic substances, poor nutrition, organ malfunction, inherited disorders, or risky personal behavior

3. 4. What is an infection?
Person has symptoms and medical signs of being infected by pathogen
5. What is the Immune System?
The body’s primary defense against
disease-causing pathogens that enter body
Immune system makes WHITE BLOOD
CELLS and ANTIBODIES to destroy pathogens

4. Fighting Infectious Diseases:
Nonspecific defenses: First line of Defense-
Do not discriminate between one threat and another.
Examples
THE SKIN – the body’s most important line of defense
Mucus, saliva, tears- contain enzymes to break down the cell walls of many bacteria
Stomach acid – destroy pathogens that make it as far as your stomach

7. Specific Defenses: Second Line of Defense
Attack particular disease causing agents (pathogens)
Kill foreign substances that enter body (shape-specific antibody production response)
The reaction of the body to particular pathogens

8. 6. What is passive immunity?
Antibodies passed from mother to child through breast milk
7. What is active immunity?
Developed when exposed to antigen from fighting infection (example- chicken pox) or from antigen in vaccines (shots)
White blood cells produced after exposure- (memory cells)
8. What is a Toxin?
Toxins are the poisonous wastes of
certain pathogens like bacteria
Toxins act as antigens

9. White Blood Cells (Leucocytes/Lymphocytes)
Cells made by immune system to destroy pathogens, toxins, cancer cells
Cells can tell difference between body
cells and foreign invaders (pathogens)
Types: T-cells, B-cells, phagocytes, macrophages, lymphocytes, leucocytes
What are phagocytes
or macrophages?
White blood cells that
engulf and digest
pathogens

11. Antigens
Protein molecule found on the cell membrane of a pathogen or cancer cell
Antigens cause immune system to react to presence of pathogens, toxins, cancer cells

12. Antibodies
Proteins made by WBCs that recognize and bind to antigens on pathogens.
Carried through the bloodstream to attack the pathogen causing the infection.
Antibodies attack invaders or mark them for destruction by other white blood cells- killer cells

15. Killer cells

16. Active immunity

17. What are vaccines?
Consists of a weakened or dead pathogen OR an antigen from pathogen
Injected into the body to stimulate immune system to produce antibodies that will kill pathogen that enter body in future

18. How do vaccines work?
After entering body, antibodies are produced for that specific pathogen.
After vaccination, immune system remembers pathogens by producing memory white blood cells that protect body for years.
Memory white blood cells react quickly when invasion of same pathogen occurs.

20. What can damage the immune system?
Immune system weakens with age
Stress, fatigue, some viruses attack immune system and cause disease.

21. What is HIV?
Human Immunodeficiency Virus: destroys helper T cells ( type of white blood cell)
What is AIDS?
Acquired Immune Deficiency Syndrome
occurs when immune system is weak an unable to fight off infections
The majority of helper T-cells are destroyed

22. Allergies What causes an allergic reaction?
What is an ALLERGY?
A reaction to some substance (allergen) in environment that causes runny nose, sneezing, rash, or swelling
What causes an allergic reaction?
Caused by allergens that are normally harmless

23. What are some substances that can cause an allergic reaction?
Certain foods, pollen, and chemicals from insect bites (bees/wasps)
What is the response of the immune system in an allergic reaction?
Immune system releases histamines that cause swelling, runny nose and rash
How can allergic reactions be treated?
People can take antihistamines (drug)

25. What is asthma? Disease of Respiratory System
Disease where air passages
narrow or thin which causes difficulty breathing
Triggered by respiratory infections, exercise, stress, pollutants, mold, smoke, and pollen

27. Disease can cause a Failure in Homeostasis
What is Diabetes? ENDOCRINE SYSTEM
Disease where your body is unable to produce insulin (hormone that lowers blood sugar)
As a result, one is unable to control blood glucose levels
What causes Diabetes?
Type 1 Diabetes: birth defect- Missing gene
Type 2 Diabetes: (Lifestyle) over-eating carbohydrates, poor diet and exercise

28. There is no known cure for diabetes
Can Diabetes be cured?
There is no known cure for diabetes
Current research in gene therapy/splicing
What is the treatment for Diabetes?
Strict diet and glucose monitoring
Insulin shots, insulin pumps

30. Cancer of the bone marrow or blood
What is cancer?
Uncontrolled cell division and growth
Caused byenvironment, Genetics, diet, lifestyle, smoking, drugs, drinking
Life may be threatened if immune system can’t kill cancer cells
Surgery, radiation, chemotherapy are used as treatment for cancer.
What is Leukemia?
Cancer of the bone marrow or blood

32. How does the immune system react to an organ transplant
How does the immune system react to an organ transplant? What is tissue rejection?
Immune system attacks transplant organs with foreign proteins on surface.
Transplant patient take drugs that suppress the immune system
White blood cells attack new organ

33. Antibiotic Resistance= trait that pathogens inherit (DNA) that allows them to not be harmed by antibiotics
ANTIBIOTICS: drug that will kill
pathogens like bacteria (not viruses)
Trait: Antibiotic Resistance
Pathogens are able to survive when exposed to antibiotics

35. What are infectious or communicative diseases?
Disease where pathogen can be spread through objects, sneezing, touching, food, water, insects and air

36. Examples of infectious disease: What are non infectious diseases?
Bacteria, virus, protists (flu, cold, HIV)
What are non infectious diseases?
Disease not caused by a pathogen
Can not be passed to others (contagious)
Examples of noninfectious diseases:
Cancer, asthma, heart disease

37. Immune system Video KidsHealth.org

38. Sample Regents Questions
1. Many bacteria that enter the circulatory system are engulfed and destroyed by  A.  phagocytic white blood cells B.  red blood cells C.  plasma D.  platelets

39. 2. Which molecule of the immune system attaches to bacteria, making them easier to eat by white blood cells? A. hemoglobin B. antibody C. antigen D. pathogen

40. A. enzymes B. hormones C. sugar D. antibodies
3.When a person is suffering from an infection, such as strep throat or chicken pox, his blood usually shows a significant increase in the number of
A. enzymes B. hormones C. sugar D. antibodies

41. 4. The Body is protected against harmful flu viruses by
A. red blood cells and hormones B. white blood cells and antibodies C. white blood cells and enzymes D. red blood cells and antibodies

42. 5. A vaccine can protect you against a disease because it
A. destroys toxic substances from bacteria before they make you sick. B. stimulates your immune system against the pathogen. C. kills any pathogenic bacteria in your body D. changes pathogenic bacteria into harmless bacteria

43. Don’t forget to study your notes!!

44. Referencing source