Chapter 39.1 terms

1. Pathogen2. Infectious disease 3. Koch’s postulates

Chapter 39 RQ…

1. What are disease-causing agents called?

2. What procedure is used to identify a pathogen?

3. The common cold is an example of an ___demic disease.

4. What proteins protect cells from viruses?

5. Which cells does HIV kill?

1. What is an infectious disease? Caused by disease-causing agents –

“pathogens” Examples: bacteria, protozoans,

fungi, viruses, worms, etc. They are found in soil, water,

animals, and other people They disrupt your body’s

homeostasis

Anthrax, Malaria, Athlete’s Foot, HIV, and tapeworm

2. What procedure is followed to determine what causes a disease? Lots of causes to diseases…

Genetic, wear & tear, exposure, malnutrition, pathogens (which cause infectious disease)

Koch’s postulates help discover which pathogen causes which infectious disease1. Find same pathogen in every case of the

disease2. Isolate pathogen & grow outside of organism3. Place pure pathogen in a healthy host, disease

must be caused4. Re-isolate pathogen from the new host & show

that it is the same as the original

Good Morning

3. What does it mean to be a “reservoir” of a pathogen?

Anything that could harbor a disease and potentially spread it

The human body itself is the main source of human diseases

People who have the pathogen but are not sick yet are in the “incubation period”

4. In what ways can infectious diseases be transmitted?1. Direct contact

*common cold, influenza, STDs

2. By an object*bacteria, other microorganisms

3. Through the air (coughing, sneezing)*Streptococcus, measles

4. A vector (intermediate organism)*Malaria, West Nile, Lyme disease, the

bubonic plague

Chapter 39.1 terms…

1. Endemic disease2. Epidemic3. Antibiotic

5. How do viruses and bacteria cause symptoms of a disease? Viruses…

Cause damage by taking over a cell’s DNA and organelles to make the cell make more virus

Bacteria…Most damage done by toxins that are

transported to the bloodCan inhibit protein synthesis, destroy

blood cells and vessels, produce fever, or cause convulsions by damaging the nervous system

6.Distinguish between the patterns of endemic and epidemic diseases.

Endemic Diseases that are

constantly present in the population

Ex: the common cold

Epidemic When many people

in the same area come down with the disease at the same time

Ex: influenza, typhoid fever, etc

7. In what ways can infectious diseases be treated?

Fight bacterial diseases with antibiotics (NO effect on viruses… )

Continued use of antibiotics has caused bacterial resistance – penicillin example

Streptococcus pneumoniae is now penicillin-resistant (it causes pneumonia, ear infections, and meningitis)

There are anti-viral drugs, but our best defense is our own immune system!

Answer questions (1 – 4) on page 1030.

Chapter 39.2 terms

1. Innate immunity2. Phagocyte3. Interferon

8. Distinguish between innate and acquired immunity.

Innate – the body’s earliest lines of defense and those you were born with

Acquired – when your body builds up a resistance to a specific pathogen

9. How do your skin and body secretions protect you? Mucus – keeps various parts of the

body from drying out & traps foreign substances

Gastric juice – acidic & destroys pathogens

Sweat, tears, saliva – all have lysozyme which breaks down bacterial cell walls

10. How does inflammation help fight pathogens?

Inflammation – redness, swelling, pain and heat to the injured area

It begins when damaged tissue cells and basophils release histamine

This causes the local blood vessels to dilate, and fluid leaked into the area helps destroy the toxic agents present

11. Distinguish among the white blood cell types and describe their functions. White blood cells – Phagocytes – destroy pathogens by engulfing them. They

include…- Monocytes which mature into macrophages, neutrophils, and eosinophils*macrophages (which are in body tissues) are the first defense, which then consume all pathogens & damaged cells- neutrophils (which circulate in the blood) come next- new tiny monocytes squeeze into the area & mature into phagocytes

The infected tissue, all of the dead pathogen, dead WBCs, and body fluids is called PUS

12. What are interferons? How are they produced and what do they do?

Phagocytes alone cannot destroy viruses It itself will get taken over

Interferons: proteins that protect cells from virusesThey are host-cell specific (can only

protect human cells) It is produced by a body cell that has

been infected – the message goes to non-infected cells, who then produce antiviral proteins

Chapter 39.2 terms…

1. Lymph2. Lymph node3. Lymphocyte

13. How does the immune system recognize cells that belong to you, and those that don’t?

Your cells have MHC markers that are specific to you (nametags )

Your immune system recognizes substances that enter your body as foreign by the protein markers (antigens) on their surfaces

14. What is the lymphatic system’s job?

1. To help maintain homeostasis by keeping a constant body fluid level

2. To help defend against disease

15. Describe lymph/tissue fluid, lymph nodes, and lymphocytes.

Tissue fluid – the stuff that surrounds all of your cells Made of water & dissolved substances from blood When it enters lymph capillaries it is now called

“lymph” This fluid returns to the bloodstream after if has

been filtered Lymph nodes – small mass of tissue

Contains lymphocytes to filter pathogens from lymph

Lymphocytes – a type of WBC that defends against foreign substances

Continued.. Tonsils – large clusters of lymph tissue

Form a protective ring and provide protection against pathogens

Spleen – stores lymphocytes, does not filter lymphDestroys bacteria and worn-out RBCsActs as a blood reservoir

Thymus – located above the heartStores immature lymphocytes until they

mature

16. What two immune responses make up acquired immunity? Antibody immunity

Helper T cells (made in bone marrow & matured in the thymus)

activate… B cells which become

either plasma cells… that make antibodies

AND memory B cells that stay in the bloodstream in case the infection strikes again

Cell-mediated immunity Cytotoxic T cells (stored in the

lymph nodes, spleen, and tonsils)

differentiate & clone, then…

travel to the infection site and…

Release enzymes directly into the pathogens, who then die

17. Distinguish between T cells and B cells. What do they each do?

T cells A type of

lymphocyte Produced in the

bone marrow and processed in the thymus

They activate B cells

B cells Become plasma

cells or memory cells when activated

Plasma cells make antibodies (2000 per second!)

Memory cells hang around

Chapter 39.2 terms…

1. Acquired immunity2. T cell3. B cell

18. Describe how allergies and autoimmune disorders might happen.

Allergies

When the immune system overreacts to a harmless substance

Mast cells release too much histamine

This causes sneezing, mucus production, redness

Autoimmune disorders

When the immune system attacks its own cells as foreign

Ex: Lupus, rheumatoid arthritis, multiple sclerosis

19. What is the difference between passive and active immunity? How can you acquire these?

Passive Naturally acquired

when antibodies are transferred from mom to baby through the placenta or milk

Artificially acquired when antibodies from another person are injected into someone else (ex: snakebite)

Active Naturally when a

person is exposed to antigens & produces antibodies

Artificially when a vaccine induces an immune response (kind of a “preview” for your immune system)

20. Overview the history of HIV and AIDS, and describe how it impacts the immune

system. Human Immunodeficiency Virus

kills helper T cells and leads to Acquired Immune Deficiency Syndrome

Transmitted through blood or body fluids HIV is a retrovirus. It attaches to the

receptor on a helper T cell, enters, and uses reverse transcriptase to write it’s RNA into DNA and become part of the host cell genome

For many years it continues to infect other helper T cells, and usually progresses to become AIDS

Answer questions (1 – 4) on page 1041. The End!