Immune (chapter 14)

Immune system
    The parts of the body that guard against pathogens (disease-causing
    organisms, ...
Phagocytosis
     One cell engulfing (eating) another cell
     • Neutrophils and monocytes (macrophages) are the two most...
The non-specific immune system
      The defense system that makes the body less accessible and less
      hospitable to p...
Humoral (antibody-mediated) immune system function
    • Each B cells makes and coats its surface with an antibody against...
The cell mediated immune system
      • The first step is when a macrophage engulfs a pathogen
             √ The pathogen...
Immunodeficiencies
    Disorders that weaken or eliminate the immune system
    • SCID (Severe combined immunodeficiency d...
Study problems for Immune System (chapter 14):

Problem 1) Water molecules are part of many fluids in the body, including ...
Problem 4) After each description, write B if it describes a B cell, write T if it
      describes a T cell, and write M i...
In MS, the immune system attacks, the __________________, which causes the
speed of nerve signals to decrease.



Problem ...
c) (The tonsils) cleanse the fluid in
                          b                in the respiratory system.

             ...
5)    a) The flu shot contained a non-infectious version of the flu virus, or
      perhaps just some protein fragments (a...
Bio11immune.doc
Upcoming SlideShare
Loading in...5
×

Bio11immune.doc

255

Published on

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
255
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
2
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Bio11immune.doc

  1. 1. Immune (chapter 14) Immune system The parts of the body that guard against pathogens (disease-causing organisms, such as bacteria and viruses) • Infection = An invasion of the body by a pathogen • The body’s defenses against pathogens also defend against certain cancers • The immune system distinguishes pathogens from normal body cells by the antigens present on each cell type √ Antigens = Molecules (usually proteins, carbohydrates and fats on the surface of a cell) that the immune system can interact with - Self antigens = Antigens that are made naturally as part of the body - The immune system does not attack cells displaying only self antigens - Foreign antigens = Antigens that are not a natural part of the body (such as antigens of viruses and bacteria) - The immune system attacks cells displaying foreign antigens White blood cells (WBC) (leukocytes) The blood cells that are part of the immune system • There are five basic types of WBCs, each with its own role in the defending the body WBC cell type Function Neutrophils Phagocytosis Eosinophils Phagocytosis Basophils Release histamine Monocytes Phagocytosis √ (become macrophages) Lymphocytes Roles in specific √ (There are two types: immune system B cells and T cells) Figs 12.6, 12.7, 12.8, 12.9, 12.10, 12.11; table 12.1
  2. 2. Phagocytosis One cell engulfing (eating) another cell • Neutrophils and monocytes (macrophages) are the two most active phagocytes The “battlefields” where the body defenses fight pathogens are usually the blood and the lymphatic system Lymphatic system A network of vessels and ducts throughout the body that (a) return lymph (excess tissue fluid) back to the circulatory system, and (b) filter the lymph to cleanse it of pathogens • Lymph nodes = Hollow structures located at the points where lymphatic vessels converge √ The lymph is filtered at the lymph nodes √ Many immune system cells are stationed at the lymph nodes • All lymph vessels eventually converge into either the thoracic duct or the right lymphatic duct √ These two large lymph ducts drain the lymph back into the blood Figs 14.2, 14.4, and 14.6 Problem 1 Lymphoid organs that filter/cleanse non-lymph fluids • Tonsils = filter/cleanse fluids in upper respiratory system • Peyer’s patches = filter/cleanse fluids in digestive system • Spleen = filters/cleanses blood Fig 14.9 Problem 2 The body has two defensive systems: • The non-specific (innate) immune system • The specific immune system
  3. 3. The non-specific immune system The defense system that makes the body less accessible and less hospitable to pathogens in general (but does not target specific pathogens) • Skin = Physically blocks pathogens from entering the body • Phagocytes = WBCs that engulf pathogens √ The three phagocytic WBCs: Neutrophils, Eosinophils, and Monocytes/Macrophages • Interferons = Proteins that inhibit viruses from entering cells • Fever = Elevated body temperature √ Inhibits bacterial growth √ Speeds up body defenses • Complement = Blood proteins that rupture pathogen cell membranes • Inflammation = The redness, heat, swelling, and pain in injured tissues √ The redness and swelling are caused by basophil WBCs releasing histamine, a molecule that makes the capillaries leaky so WBCs can exit the blood vessel to attack pathogens in the injured tissue √ Injured cells release molecules that attract WBCs and activate pain receptors The specific immune system The defense system that makes precise attacks against individual specific pathogens by recognizing their foreign antigens • Cells of the immune system: Lymphocytes (T cells and B cells) • The immune system has “memory”: It attacks pathogens more effectively if it has encountered them before • The immune system has two branches: The humoral immune system and the cell mediated immune system • The humoral immune system attacks pathogens using antibodies (proteins that bind to the pathogen’s antigens) √ B cells make the antibodies and release them into the lymph and blood • The cell mediated immune system attacks pathogens using cells √ T cells (activated by macrophages) destroy pathogens Figs 14.13 and 14.14
  4. 4. Humoral (antibody-mediated) immune system function • Each B cells makes and coats its surface with an antibody against only one specific foreign antigen √ We have thousands of different B cells so we have antibodies against thousands of different foreign antigens • If the surface antibody binds its antigen, the B cell divides repeatedly √ This produces thousands of identical clones of the B cell • Most of the clones release their antibodies, allowing the antibodies to circulate widely in the body • Memory B cells = The clones that retain their antibodies √ Memory cells remain ready to divide in future encounters with the antigen • Circulating antibodies coat the outside of any pathogen cell that has the antigen √ Complement proteins rupture (“fix”) antibody-coated cells √ The antibody coat prevents the pathogen cell from functioning properly √ The antibodies link together (“agluttinate” or “precipitate”) the pathogen cells, which helps the body eliminate them Figs 14.14, 14.15, and 14.16
  5. 5. The cell mediated immune system • The first step is when a macrophage engulfs a pathogen √ The pathogen’s foreign antigens are displayed by the macrophage on its surface • Each T cell is programmed to attack only one specific foreign antigen √ We have thousands of different T cells, each programmed to attack a different foreign antigen • T cells become activated only after they encounter a macrophage displaying their specific foreign antigen • Once activated, T cells divide repeatedly, producing thousands of clones of themselves • The clones of the activated T cell come in three types: √ Killer T cells = They attack the pathogen directly √ Helper T cells = They make B and T cells divide √ Memory T cells = They remain ready to divide in future encounters with the pathogen Figs 14.13 and 14.14 Problems 4, 5, and 6 Detrimental immune system reactions • Autoimmune diseases = Any disorder caused by the immune system attacking self antigens in specific tissues or organs √ Examples: Multiple sclerosis, rheumatoid arthritis, lupus • Allergies = Excessive (tissue damaging) responses to harmless antigens in the environment √ Effects = Rash (hives), watery eyes and nose, itching, asthma √ Anaphylactic shock = A life-threatening allergic response to allergens that enter and circulate within the body • Rejection of organ transplants √ Immune suppressive therapy reduces rejection, but increases patient’s susceptibility to pathogenic diseases Problems 7 and 8
  6. 6. Immunodeficiencies Disorders that weaken or eliminate the immune system • SCID (Severe combined immunodeficiency disease) = a congenital (genetically inherited) absence of the immune system • AIDS (Acquired immune deficiency syndrome) = An acquired disease in which the HIV virus destroys Helper T cells √ Helper T cells are needed to make B and T cells divide √ There is a months to years delay between viral infection and onset of immune system deterioration √ AIDS is spread by exchange of bodily fluids √ 1 million victims in US; 40 million worldwide Problems 9 and 10
  7. 7. Study problems for Immune System (chapter 14): Problem 1) Water molecules are part of many fluids in the body, including lymph, tissue fluid, and blood. In the blank spaces below, use the numbers 1 – 4 to indicate the order a molecule of water would encounter the following fluids and body parts, as it moves from the blood to the end of the lymphatic system. The thoracic duct _____ The plasma _____ A lymph node _____ Tissue fluid _____ Circle the answer above where the water would re-enter the blood. Draw a box around the answer above where the molecule would find large numbers of immune cells Draw a star over the answer above that swells when we are fighting an infection. Problem 2) In the figure below, write the letters a – e to show the correct location of the following structures. For structures a, b, and c on the list, write what body fluids they filter and cleanse. For items d and e on the list, name of the specific lymphatic duct that they describe. a) Peyer’s patches b) The spleen c) The tonsils d) The site where lymph from the right forearm re-enters the circulatory system. e) The site where lymph from the right thigh re-enters the circulatory system. Problem 3) One of the non-specific body defenses is called the inflammatory response. The inflammatory response, which occurs in an injured tissue, includes a) making the capillaries leaky, and b) activating pain receptors. Explain briefly how each of these two functions protects the body.
  8. 8. Problem 4) After each description, write B if it describes a B cell, write T if it describes a T cell, and write M if it describes a Macrophage cell. Some blanks may require more than one answer. a) Lymphocytes: _____ b) Makes antibodies: _____ c) Part of humoral immune system: _____ d) Part of cell-mediated immune system: _____ e) It works with the complement proteins to destroy pathogen cells: _____ f) Has memory cells: _____ g) It requires the help of a macrophage cell to become activated to fight pathogens: _____ Problem 5) You receive a flu shot (a vaccination against that year’s flu virus). A few months later, you are exposed to a person with the flu. Thanks to the flu shot, your body is able to fight off the virus so quickly that you never feel ill. Explain a) What was in the flu shot? b) What did the flu shot change in your body that allowed you to fight off the flu virus? c) Why do you have to get the flu shot again next year? Be as specific as possible in your answers. Problem 6) If you are exposed to a pathogen that your body has never encountered before, the immune system makes new B and T cells. Most of the new B and T cells fight the pathogen, but some B and T cells (called memory B cells and memory T cells) do not. Explain why your body makes memory B cells and memory T cells. Problem 7) Multiple sclerosis (MS) is a disease where the immune attacks the body’s own tissues. Diseases of this type are called ______________ diseases.
  9. 9. In MS, the immune system attacks, the __________________, which causes the speed of nerve signals to decrease. Problem 8) Patients with autoimmune diseases often treated by giving them hormones that decrease the activity of the immune system. Name the hormones that decrease the immune system’s activity: __________ (you may need to review your notes on the endocrine system to answer this question). What is an unintended and dangerous side effect of lowering a patient’s immune system activity to treat an autoimmune disease? Problem 9) What is the difference between HIV and AIDS? Problem 10) The HIV virus only destroys helper T cells, which are only a small part of all your immune cells. Explain how HIV can totally destroy the activity of the immune system by infecting only helper T cells. Answers to Study Problems for Immune System (chapter 14): 1) 4 (circled) 1 3 (box and star) 2 2) a (Peyer’s patches) cleanse the c fkuids in the digestive system. d e b) (The spleen) cleanses the blood.
  10. 10. c) (The tonsils) cleanse the fluid in b in the respiratory system. a d) The right lymphatic duct. e) The thoracic duct. 3) a) Making the capillaries leaky allows immune system cells to move from the blood into the tissue, to fight infection in the injured tissue. b) Activating pain receptors in the injured tissue discourages us from using the injured body part, which would aggravate the injury. 4) a) B and T b) B c) B d) T and M e) B f) B and T g) T
  11. 11. 5) a) The flu shot contained a non-infectious version of the flu virus, or perhaps just some protein fragments (antigens) of the flu virus. b) The flu shot caused an increase in the B and T cells of your body that fight that particular strain of the flu virus. c) The flu virus mutates every year. Because each cell of your immune system fights just one specific pathogen, the increased B and T cells that this year’s flu shot gave you are only attack this year’s flu virus. They will not be able to fight next year’s flu virus, so you need a new shot every year. 6) The memory B and T cells don’t fight the pathogen on the first encounter, but if you are exposed to the same pathogen a second time (perhaps years later) the memory B and T cells will allow your immune system to fight the pathogen more quickly and effectively than on your first encounter. 7) Autoimmune Myelin sheath of neurons 8) Glucocorticoid hormones (such as cortisone and cortisol). Lowering the activity of the patient’s immune system will make the patient more susceptible to infections. 9) HIV is a virus. AIDS is the disease that the virus causes. 10) The helper T cells are only a small part of all your immune cells, but helper T cells play the critical role of activating other important cells of the immune system (such as B cells and killer T cells). Therefore, when a person has AIDS, they still have B cells and killer T cells, but without helper T cells these cells cannot effectively battle pathogens.

×