Chapter 40 The Immune System

A disease causing agent *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 pathogens A disease causing agent Function infection cells two nonspecific defenses specific defenses

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 out skin, mucus sweat and tears skin most secretions bacteria

SKIN

Mucus, saliva, and tears 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 _____________________. lysozymes cell walls Oil sweat glands acidic mucus ciliated cells

inflammatory response 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 defense tissue damage infection pathogen white blood cells

Red blood cells Platelets White blood cell (T-Cell)

2) The blood vessels near the wound _________ and to move the cell 2) The blood vessels near the wound _________ and to move the cell into the infected area. 3) Many of the white blood cells are _____________ that __________ the pathogens. 4) This response causes ___________________________. expand phagocytes engulf pain swelling, redness, and

specific temperatures speeds up the heart rate 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 ___________. raise core temperature Fever infection survive specific temperatures speeds up the heart rate faster

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. proteins interferon 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 specific immune response substance antigen

1. Antigens are recognized by ________ types of _______________________. a) _________________ (B cells) - Provide immunity against antigens and pathogens in the ____________. - This is called ___________________. two lymphocytes B- lymphocytes body fluids humoral immunity

b) ______________ (T cells) - Defend against ________________ and pathogens inside living cells. - This is ______________ __________. T Lymphocytes abnormal cells cell-mediated immunity

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. antibodies bloodstream stop memory B cells same antibodies same secondary response divide new plasma cells

PRIMARY RESPONSE (initial encounter with antigen) Antigen Antigen receptor on a B cell Antigen binding to a B cell Cell growth, division, and differentiation Clone of cells Memory B cell Plasma cell Antibody molecules Later exposure to same antigen SECONDARY RESPONSE (can be years later) Cell growth, division, and further differentiation Larger clone of cells Plasma cell Memory B cell Antibody molecules Figure 24.9

Primary and Secondary Response Curves

1. Antibodies are shaped like a _____. 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-binding sites “Y” 2 enzyme shape

Antigen molecules Variety of B cells in a lymph node Antigen receptor (antibody on cell surface) Cell growth division, and differentiation Clone of many effector cells secreting antibodies Endoplasmic reticulum Antibody molecules Figure 24.7

a) Because there are so many different 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 millions antibodies own cells against cannot alone

T-cells divide and _________________ 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 ___________________. differentiate Killer T Cells destroy antigen Helper T Cells Killer differentiate memory T Cells

Helper T Cells Microbe Macrophage Antigen from microbe (nonself molecule) Self protein displaying antigen T cell receptor Binding site for self protein Helper T cell Binding site for antigen Figure 24.13A

c) __________________________ - Releases a substance that ___________________________ or shuts down the _______________ when the __________ is under control. d) _________________________ - Will cause a _________________________ if the same antigen appears again. Suppressor T Cells slows the development killer T Cells infection Memory T Cells secondary response INFECTED CELL Cytotoxic T cell Foreign antigen Hole forming

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 proteins T 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 rejection donors recipient suppress

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 pathogen immunity

a). More than _____ different human. diseases can be _________________ 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 prevented stimulate plasma cells natural exposure vaccines

B. Passive Immunity ___________________ = 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. Passive immunity another animal temporary attack naturally intentionally

                                                              

AIDS (Acquired Immune Deficiency Syndrome) AIDS is a ___________ infection. - AIDS destroys_______ __________. - The cause of AIDS is _______ (Human Immunodeficiency Virus) viral Helper T cells HIV

reverse transcriptase How HIV works 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. Helper T Cells retrovirus RNA reverse transcriptase Viral RNA DNA

a. These parts are assembled and then 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. Viral DNA virus leave Virus emerging from a T cell.

B. They grow ________ T-cells therefore they 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 ________. inside antibodies T cells humoral cell-mediated T cells diseases 200/mm3