Download M1-3 Immune System

Disease and the Immune System Ch37 M1-3
I.
Disease
A. General Facts
1. Robert Koch – discovered bacteria as cause of disease
B. Defense Mechanisms (1st line)
1. Skin
a. Physical barrier to pathogens
b. Sweat, oil and waxes – contain anti-microbial agents
c. Good bacteria (natural flora) competes with “bad” bacteria
2. Mucous membranes
a. line respiratory and digestive systems
b. secrete mucous – traps bacteria
c. cilia – line many areas/ sweep out debris/ swallowed and
destroyed by stomach acid
II.
Inflammatory Response
A. Mode of Action
1. When injury occurs
a. damaged cells release chemicals
b. Histamine – increases blood flow
Increases permeability of capillaries
Increased fluid and WBC’s go to injury
Causes swelling and pain
2. Damaged blood vessels
a. platelets and clotting proteins initiate blood clotting
3. WBC response – several different kinds
a. Phagocytes – engulf pathogens
b. Neutrophil – (type of phagocyte)
c. Natural killer cells – focus on cells with virus or cancer
*Pus is a sign of WBC’s and is dead microorganisms and dead
cells
B. Other Nonspecific Defenses
1. Interferon – protein that inhibits viral reproduction
2. Fever –
a. Low fever causes enhanced immune response
b. Low fever suppresses growth bacteria
c. High fever inactivates enzymes and can be fatal
III.
Specific Defenses
*Nonspecific – 1st line of defense – When overcome the 2nd line comes into
play
A. Immune System
1. Fights off invading pathogens and cancer
2. Several organs and WBC’s
a. Bone Marrow – manufactures WBC’s
b. Thymus – gland in upper chest/ immune function
c. Lymph nodes – filter pathogens from blood
d. Spleen – organ behind stomach/ filters blood stream/ stocked
with WBC’s
e. Lymphocytes – (WBC’s)
2 types: B and T cells
B cells – produced in bone marrow
T cells – mature in thymus
B. Recognizing Pathogens
1. Immune Response – when lymphocytes launch attack
2. Antigens – any substance recognized as foreign invader
(pathogens, bacterial toxins, insect venom and pollen)
3. How WBC’s recognize antigens
a. Receptor proteins cover WBC cell membrane
b. Recognize and bind to antigens
c. Each WBC has unique receptors to respond to different
pathogens
d. Only proper WBC’s can attach (cold virus WBC won’t attack
influenza)
4. Immune Response – 2 parts:
a. Cell mediated response – T cells
b. Humoral response – B-cells
5. Method of immune response
a. 1st step – Macrophage engulfs pathogen
b. Macrophage displays pathogen antigens on its own surface
c. Helper T cells with matching receptors line up to macrophage
d. Helper T cells release interleukin 1 and 2
6. Interleukin1 and 2
a. Stimulates helper T cells to divide
b. T cells destroy any invaded body cells by puncturing cell
membrane
c. T cells also destroy foreign tissue (organ transplants) and cancer
cells
7. Humoral Immune Response
a. Interleukin 2 stimulates B cells to divide
b. Plasma cells (special B cells) produce antibodies
c. Antibodies – defensive proteins identical to antigen receptors/
bind to antigens and deactivate them
8. After Infection is Over
a. Most cells die
b. Some B and T cells remain as memory cells
c. Memory cells – offer long-term protection/ prevent future
disease from the same organism
d. 2nd infection – memory cells quickly divide and overcome
pathogen
e. Primary response – 1st encounter disease (usually get sick)
f. Secondary response – later encounters with disease/ Due to
memory cells/ rarely get sick
C. Vaccination
1. Invented by Edward Jenner
a. Heard milkmaids contracted cowpox/ rarely got smallpox
b. Took matter from cowpox sore and injected into 8 yr old
c. 2 mo later – injected 8yr old boy with smallpox/ he didn’t get
sick
d. **smallpox vaccines were given around the globe/ last case in
1977
2. Louis Pasteur
a. 1881 – created cholera vaccine
3. Vaccines
a. Use pieces of pathogens
b. Cause creation of antibodies
c. Control: polio, measles, mumps, tetanus, and diphtheria
d. Boosters – offset chance of immunity wearing off
D. Allergies
1. Allergy – create antibodies against harmless invader (pollen)
E. Autoimmune
1. Lymphocytes react to own cells and attack
2. Includes: lupus, type I diabetes, rheumatoid arthritis, multiple
sclerosis
F. AIDS (Acquired Immunodeficiency Syndrome)
1. AIDS – recognized 1981/ caused by virus
2. Immune system – loses ability to fight
3. Virus – attacks T cells/ manufacture lg numbers virus particles
(HIV – human immune deficiency virus)
4. Eventually number of T cells decreases/ prevents entire immune
system from functioning (full blown AIDS)
5. Transmission – body fluids
a. sexual intercourse (all kinds)
b. syringes
c. blood transfusions (fairly safe now)
6. Treatment
a. Evolves quickly (difficult to create vaccine)
b. Current “cocktail” of many drugs is mode control
.