Chapter 40

The Immune System

*The ____________________ is the body’s main defense against _________________.- Pathogens = __________________________.______________ = To fight _____________ through the production of _______ that inactivate foreign substances or other cells.*** There are _________ types of defense mechanisms that fight infection: ________________ _______________ and _____________________.

immune system

Function

pathogens

A disease causing agent

cellsinfection

two

defensesnonspecific

specific defenses

I. Nonspecific Defenses (includes both _______________ and __________________ barriers)A. First Defenses

1. Keeping pathogens _________.a. includes

___________________ _____________________ _____.

b. The __________ is the most important and it keeps

_____ pathogens out!c. ________________ can kill

many different types of ______________.

physical chemical

skin

outskin, mucus

sweat and tears

most

secretions

bacteria

SKIN

1) _____________________ contain __________ which can kill the ____________.

2) ________ and ___________ make an _____________ environment that kills bacteria.

3) Openings like the mouth and nose are protected by _________ and _____________________.

Mucus, saliva, and tears

lysozymescell walls

sweat glandsOil

acidic

mucusciliated cells

B. Second Line of Defense

1. What happens when the pathogens enter your body and multiply?

a. The _________________________ is activated = a_________________________

reaction to ___________________ caused by injury or ________________.

1) When a ___________ is detected, the immune system makes millions of __________________________ (they fight infection!).

inflammatory response

nonspecific defensetissue damage

infectionpathogen

white blood cells

Red blood cells

Platelets

White blood cell (T-Cell)

2) The blood vessels near the wound _________ and to move the cellinto the infected area.

3) Many of the white blood cells are _____________ that __________

the pathogens.

4) This response causes ___________________________.painswelling, redness, and

engulfphagocytes

expand

b. The immune system can also ________ the ________________________ of the body when it is necessary.

1) __________ = A raise in the body’s core temperature in response to

__________.

2) The temperature increase can kill many sensitive pathogens that can only ________________ at ___________________________.

3) An increase in temperature also ____________________________ which moves the white blood cells through the body ___________.

core temperature

Fever

infection

survivespecific temperatures

speeds up the heart rate

faster

raise

C. Interferon

1. Some cells that are infected with a virus makes a group of

________________called___________.

a. Interferon __________

the virus’s ability to make proteins and reproduce.

proteinsinterferon

slows

II. Specific Defenses

A. If a pathogen can get past the_____________________________ the immune system will attack a _____________ type of pathogen through an __________________.

B. The _____________ that triggers the immune response is called an

______________. (ex. Viruses, bacteria, etc.)

nonspecific defense

specificimmune response

substance

antigen

1.Antigens are recognized by ________ types of _______________________.

a) _________________ (B cells)

- Provide immunity against antigens and pathogens in the ____________.

- This is called ___________________.

twolymphocytes

B- lymphocytes

body fluids

humoral immunity

b) ______________ (T cells)

- Defend against ________________ and pathogens inside living cells.

- This is ______________ __________.

T Lymphocytes

immunitycell-mediated

abnormal cells

C. Humoral Immunity

1. B cells recognize a pathogen and then __________ rapidly, making

___________________and

__________________.

a) Plasma cells release ___________ = proteins that

recognize and

bind to antigens.

multiply

plasma cells

memory B cells

antibodies

2.The _______________ travel in the ___________________ to get to the foreign pathogens where they overwhelm them.

3.The plasma cells die out and ________ producing the antibodies as the infection is overcome.

a) Millions of ______________________ cells are left over and are able to produce the __________________.

b) If the __________ antigen enters the body again, a _________________ is triggered and the memory B cells ____________ to make new _______________________ with same antibodies.

stop

memory B cells

same antibodies

samesecondary response

dividenew plasma cells

bloodstreamantibodies

Figure 24.9

PRIMARY RESPONSE(initial encounterwith antigen)

Antigen

Antigen receptoron a B cell

Antigen bindingto a B cell

Memory B cell

Antibodymolecules

Plasma cell

Cell growth,division, anddifferentiation

SECONDARY RESPONSE(can be years later)

Cell growth,division, and furtherdifferentiation

Larger cloneof cells

Plasma cell

Antibodymolecules

Later exposure to same antigen

Memory B cell

Clone ofcells

Primary and Secondary Response Curves

D. Antibody Structure

1. Antibodies are shaped like a _____.

2. ____ identical binding sites for antigens.

3. Like an _____________, the _____________ of the binding site determines which antigens it can bind with.

Antigen-bindingsites

“Y”

shapeenzyme

2

Figure 24.7

Antigen molecules

Variety ofB cells in a lymph node

Cell growthdivision, anddifferentiation

Clone of manyeffector cellssecretingantibodies

Antibodymolecules

Antigen receptor(antibody oncell surface)

Endoplasmicreticulum

a) Because there are so many different _______ of antigens, our bodies must

make ________________ of different types of ____________________.

E. Cell-Mediated Immunity

1. Cell Mediated Immunity = The body’s defense against it’s ________________

when they turn ___________ the body (i.e. cancerous cells, virus-infected cells, fungi, protists).

2. Antibodies __________________ destroy them.

types

cannot alone

againstown cells

antibodiesmillions

3. T-cells divide and _________________ (become specialized in structure and function)

a) ____________________

- Locate and ___________________ bacteria, fungi, or foreign tissue that has the

____________.

b) _____________________- Activate _______ T cells to divide and

also stimulate B cells to ______________.

- They make ___________________.

antigen

Killer T Cells

destroy

memory T Cells

Helper T Cells

differentiate

differentiateKiller

Figure 24.13A

Microbe

Macrophage

Antigen from microbe(nonself molecule)

Self protein

Self proteindisplayingantigen

T cell receptor

Bindingsite for self protein

HelperT cell

Binding sitefor antigen

Helper T Cells

c) __________________________

- Releases a substance that ___________________________ or shuts

down the _______________ when the __________ is under control.

d) _________________________

- Will cause a _________________________ if the same antigen appears again.

INFECTED CELL

CytotoxicT cell

Foreignantigen

Holeforming

Suppressor T Cells

slows the developmentkiller T Cells

infection

Memory T Cellssecondary response

F. Transplants

1. Killer T cells can make _____________________ difficult.

2. Body cells have _____________________ on their surface that the recipient’s ____________ do not recognize.

organ acceptance

marker proteinsT cells

a) The immune system begins to ________________ the transplanted organ

in a process called ___________________.

b) This is why it is important for __________ to have many of the same cell markers as

the __________________.

c) Recipients must take drugs that _____________ cell-mediated immunity.

attack

suppress

recipient

donors

rejection

III. Acquired Immunity

A. Active Immunity

1. _________________________ = Immunity produced from a vaccine.

2. Vaccination = The injection of a ___________________________ in

order to produce ____________________.

Active Immunity

weakend pathogenimmunity

a) More than _____ different human diseases can be _________________ by vaccination.

b) Modern vaccines ____________ the immune system to create millions of different _______________________.

3. Active immunity can result from _________________ or from _____________.

20

stimulate

prevented

plasma cells

natural exposurevaccines

B. Passive Immunity1. ___________________ = Antibodies from

____________________ are injected into the bloodstream.

2. Passive immunity is __________________ because the body’s immune system will ______________ the foreign antibodies.

3. Passive immunity can also occur __________________ or ________________.

Ex.- Antibodies produced by a pregnant mother can be passed through the placenta (or through breast milk) to the fetus. This protects an infant inthe first few month’s of it’s life.

naturally

another animalPassive immunity

temporary

intentionally

attack

                                                        

      

AIDS (Acquired Immune Deficiency Syndrome)

I. AIDS is a ___________ infection.

- AIDS destroys_______

__________.

- The cause of AIDS is

_______ (Human Immunodeficiency Virus)

HIV

T cells

Helper

viral

How HIV worksA. HIV targets ______________

1. HIV is a _______________ = a virus that carries it’s information in the form

of _____.2. When a HIV virus attaches to a helper T Cell, it injects it’s RNA which uses a

process called ______________________.a. The ____________ forces the cell’s DNA to make copies of itself. Some become part of the original cell’s ______ while others

stay in the cytoplasm.

reverse transcriptase

retrovirus

RNA

Viral RNA

DNA

Helper T Cells

3. When the ______________ is activated, the host cell begins to make the parts of the

________.

a. These parts are assembled and then

__________ the cell to infect other cells.

Virus emerging from a T cell.

Viral DNA

virus

leave

B. They grow ________ T-cells therefore they are not affected by ____________.

1. Over time _________ are destroyed which

lowers ____________ and _____________

immunity.

a. The fewer number of __________

means that the body is more susceptible to other

__________.

2. A person is diagnosed with AIDS when their

T cell count goes below ________.200/mm3

diseases

T cells

humoralcell-mediated

T cells

antibodiesinside