THE IMMUNE SYSTEM
What it is and its role in the body
Immune System


Purpose is to keep infectious microorganisms out of
the body and destroy those that enter.
Made up of a complex system of organs and cells
Organs
involved are
called
lymphoid
organs
White Blood Cells

Also called Leukocytes
 Phagocytes
 Attack
invading pathogens
 Macrophages
 Type
of Phagocyte
 Reacts
by engulfing pathogen and making antigens
identifiable
Immune Response

Antigens
 Substances

that can trigger an immune response
Antibody
A
protein that acts against a specific antigen
Lymphocytes

Type of infection-fighting white blood cell
 Patrol


for pathogens
Originate in bone marrow
Two types of lymphocytes
B
cells
 Finish
T
cells
 Finish

maturing in bone marrow
maturing in thymus
Once matured, some stay in lymphoid organs while
others go out on patrol
T cells

3 types
 Helper
 Facilitates
production of B cells and Killer T cells
 Killer
 Attack
and destroy infected body cells, not the pathogen
 Suppressor
 “Commanding

Officers”
Coordinate actions of other T cells
B cells

Produce antibodies
 Each
cell is programmed to make one type of antibody
that is specific to a type of pathogen
 Antibodies
 Attach
will:
to antigens to mark them for destruction
 Destroy invading pathogens
 Block viruses from entering body cells
White Blood Cell Chart
White Blood Cells/Leukocytes
Phagocytes
Macrophages
Lymphocytes
B cells
T cells
Helper
Killer
Suppressor
Immune Response
1.
2.
3.
4.
5.
6.
7.
8.
Pathogens Invade
Macrophages engulf pathogen
Macrophages digest pathogen; T cells recognize
antigens of pathogen as invaders
T cells bind to antigens
B cells bind to antigens and helper T cells
B cells divide and produce plasma cells
Plasma cells release antibodies into bloodstream
Antibodies bind to antigens to help other cells identify
and destroy pathogens
Common Pathogens that Cause
Infectious Diseases

Viruses

Bacteria

Fungi

Protozoa

Rickettsias
Virus

Piece of genetic material surrounded by a protein
coat
Reproduce by invading cells of living organisms
Multiply then begin taking over other cells
Most common are the cold and influenza

Antibiotics DO NOT work against viruses



Bacteria



Single-celled microorganisms
Most are harmless and some are helpful
Disease-causing produce toxins


Substances that kill cells or interfere with their functions
Antibiotics kill bacteria
Spreading Disease

Direct Contact
 Touching,

Indirect Contact
 Sharing

kissing, etc.
contaminated objects, vectors such as insects
Airborne
 Sneezing
or coughing pathogens out of your body can
enter another’s, fungal spores
Vaccinations




Vaccinations are weak or dead pathogens
intentionally put into the body
Immune response takes over and develops the
antibodies to defend against the actual disease if it
ever enters the body
Why do we need a flu shot every year?
Why isn’t there one vaccine for the common cold?
Allergic Reactions

Allergy
Disorder of the immune system
 Allergic Reactions are the result of the immune system
dramatically responding to what it interprets as a threat
(dust, pollen, pet dander, etc.)
 Allergens



Substances that cause allergic reactions
Reactions can range from minor (watery eyes, itchiness, slight
wheezing, runny nose) to major (hives, swelling of tongue
and throat, difficulty breathing, dizziness, headache,
stomach issues, shock, or loss of consciousness)
Anaphylactic Shock

Life threatening reaction to allergens





Sudden drop in blood pressure occurs
Usually caused by reactions to allergens in food, insect bites
or stings, drug, or chemical
People who are aware of life-threatening allergies may
have an EpiPen ready to use
EpiPen – single dose of epinephrine to be administered to
the outer thigh only.



People who suffer major reactions can go into anaphylactic shock.
Increases heart rate and strength of heart beat
Dr. prescribed only!!
When an EpiPen needs to be used medical attention is
needed immediately after administration
HIV, AIDS, AND STI
HIV and AIDS

HIV
 Human
 Leads




Immunodeficiency Virus
to AIDS (Acquired Immune Deficiency Syndrome)
Destroys specific T cells (CD4+ T cells) crucial to
helping the body fight infections
HIV can exist for years before leading to AIDS
HIV levels increase while the T cells decrease
Leaves body more prone to infections and diseases
How HIV Works
1.
HIV Virus in blood
2.
Attaches to T cell and empties contents
3.
4.
5.
6.
7.
8.
Viral DNA is created and inserts into cell’s DNA
Infected cell divides with new DNA code
Cell division creates raw protein material
Raw infected material is packaged into an immature virus cell
Leaves infected cell through “budding”
New immature cell matures and then attacks another healthy cell
New infected cells are slightly different (mutations) than where they
came from
Why is this a major problem??
HIV Symptoms



Very few, if any symptoms show at first
Roughly 2 to 3 months after contraction, flu-like
symptoms will show including fatigue and swollen
lymph nodes in neck and groin
Symptoms may go away
HIV Later Stage Symptoms

Later stage symptoms
 Rapid
Weight Loss
 Recurring night sweats and fever
 Extreme fatigue
 Prolonged lymph node swelling
 Diarrhea lasting more than a week
 Sores at the mouth, anus, and genitals
 Red, brown, pink, or purple splotches under the skin or
inside mouth, nose, or eyelids
HIV Treatment

Antiretroviral Therapy (ART)
 Drugs
do not kill the virus but slow its ability to spread
and infect healthy cells
 About
30 different drugs available
 Block
different stages of the virus’ reproduction and
infection process
Possible Cure?
AIDS

Acquired Immunodeficiency Syndrome
 Is
not HIV but occurs during late stages of HIV
 Immune system becomes deficient
 Diagnosed when patient contracts one or more specific
Opportunistic Infections (OI), certain cancers, or has a
very low CD4+ T cell count
Other Sexually Transmitted Infections


Half of all new sexually transmitted infections occur
among people aged 15-24
Common STIs are:
 Bacterial
Vaginosis (BV)
 Chlamydia
 Gonorrhea
 Viral Hepatitis
 Genital Herpes
 Human Papillomavirus (HPV)
Sexually Transmitted Infections
 Pelvic
Inflammatory Disease (PID)
 Syphilis
 Trichomoniasis
 Pubic Lice
 Scabies
Chlamydia




Affects both men and women
Sexually active women age 25 and younger need
testing every year
Easy to cure yet an untreated infection can impact a
woman’s ability to have children later in life by
causing permanent damage to reproductive organs
“Silent Infection”
Chlamydia


Most people show no symptoms when contracted
Women

Starts in the cervix or urethra then spreads to uterus and
fallopian tubes



Leads to Pelvic Inflammatory Disease (PID)
Could cause unusual discharge from vagina or burning
sensation when urinating
Men
Could have discharge from penis or burning sensation
 Pain and swelling in one or both testicles (epididymitis) could
occur

Treatment for Chlamydia

Antibiotics
 During

treatment, abstain from sexual activity (7 days)
Repeat infection can occur
Gonorrhea

CDC estimates that about 820,000 people contract
gonorrhea annually
 Estimated

that 570,000 are 15-24 years old
Affects both men and women
Gonorrhea

Men
Burning sensation when urinating
 White, yellow, or green discharge from penis
 Epididymitis can occur
 Symptoms appear between 1-14 days after infection


Women
Usually show no symptoms
 Can be mistaken for bladder or vaginal infection
 Discharge, burning when urinating, or bleeding between
periods can occur
 Can lead to PID

Treatment for Gonorrhea



Left untreated, can be life-threatening by
spreading to blood and joints
Different antibiotics can be prescribed
Drug-resistant gonorrhea has become more
prevalent
Human Papillomavirus (HPV)




Most common STI (approx. 79 million Americans
have it)
About 14 million new infections per year
CDC estimates that nearly ALL sexually active men
and women contract it at some point in life
Can be acquired through oral, vaginal, or anal sex
HPV



In 90% of cases, the immune system clears HPV on
its own without causing health problems
Can be contracted even if infected person is
showing no signs or symptoms
HPV that does not go away can cause genital warts
or cancers
HPV

Different types of HPV infections can lead to either
Genital Warts
 Cancers

Cervix, Vulva, Vagina
 Penis
 Anus, Throat, Tongue and Tonsils



Cancers can develop many years after HPV is
contracted
No way to forecast who gets warts or cancer
HPV Prevention

Vaccination should be for boys and girls between ages
11 and 12
Given as three shots over six months
 All three doses are necessary
 “Catch-up” vaccines are available for men and women ages
21-26


Women should get screened regularly for cervical
cancer



Ages 21-65
Abstinence
Correctly used latex condoms can reduce risk

Areas not covered by condom still at risk