The Immune System & Non- Infectious Disease. Ch. 18: Sections 1, 2, & 4

Transcription

1 The Immune System & Non- Infectious Disease Ch. 18: Sections 1, 2, & 4

2 What is the Immune System? The purpose of the immune system is to: keep infectious microorganisms, such as certain bacteria, viruses, and fungi, out of the body to destroy any infectious microorganisms that do invade the body.

3 Immunity Vocabulary Pathogen - any disease-producing agent, especially a virus, bacterium, or other microorganism. Infectious Disease - A disease resulting from the presence and activity of a pathogenic microbial agent

4 Bacteria Vs. Virus Bacteria Virus Ribosomes Present Absent Living attributes Living organism Opinions differ on whether viruses are a form of life or organic structures that interact with living organisms. Number of cells Unicellular; one cell No cells; not living DNA and RNA floating freely in DNA or RNA enclosed inside a coat of Structures cytoplasm. Has cell wall and cell protein. membrane. Cell wall Peptidoglycan/Lipopolysaccharide No cell wall.protein coat present instead. Treatment Antibiotics Ear Infections Vaccines prevent the spread and antiviral medications help to slow reproduction but can not stop it completely. Tetanus or Terberculosis Enzymes Yes Yes, in some Nucleus No No Virulence Yes Yes Infection Localized Systemic Benefits Some bacteria are beneficial (e.g. certain bacteria are required in the gut) Viruses are not beneficial. However, a particular virus may be able to destroy brain tumors (see references). Viruses can be useful in genetic engineering. Reproduction Fission- a form of asexual reproduction Invades a host cell and takes over the cell causing it to make copies of the viral DNA/RNA. Destroys the host cell releasing new viruses.

5 Kinds of Pathogens Continued Fungi Protist Reproduction Varies; sexual or asexual. Reproduction is done by asexual and sexual means. Kingdom Fungi Protista*, Haeckel, 1866 Definiton A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (British English: moulds), as well as the more familiar mushrooms. Ringworm is a common Fungal Infection. any of various one-celled organisms, classified in the kingdom Protista, that are either free-living or aggregated into simple colonies and that have diverse reproductive and nutritional modes, including the protozoans, eukaryotic algae. Malaria is a common Protist Disease.

6 Pathogenicity Pathogens can spread through: contact with either an environmental vector; soil, food, or water a biological vector; or an infected animal.

7 The Body s Defenses In the 1 st line of defense, the surfaces of the skin, nose, mouth, and stomach function as barriers to pathogens. These barriers capture and kill most pathogens with which you come into contact.: Inflammatory Response: An important non-specific defense against tissue damage. It begins when injured tissue cells release chemical signals that activate endothelial cells of nearby capillaries to localize an infection or damage to tissue.

8 The Body s Defenses Continued Immune Response: Activation of the immune response typically begins when a pathogen enters the body. Macrophages that encounter the pathogen ingest, process and display the antigen fragments on their cell surfaces.

9 Defense Systems & Explanations White Blood Cells The white blood cells are continually on the lookout for signs of disease. When a germ does appear, the white blood cells have a variety of ways by which they can attack. Some will produce protective antibodies that will overpower the germ. Others will surround and devour the bacteria. Inflammation symptoms of inflammation are redness, swelling, heat, and pain, which are caused by increased blood flow into tissue. These cytokines and other chemicals recruit immune cells to the site of infection and promote healing of any damaged tissue following the removal of pathogens.

10 Defense Systems Continued Fever The above-normal temperatures are thought to help defend against microbial invasion because they stimulate the motion, activity, and multiplication of white blood cells and increase the production of antibodies. At the same time, elevated heat levels may directly kill or inhibit the growth of some bacteria and viruses that can tolerate only a narrow temperature range.

11 Body Defenses Continued T-Cells any of several closely related lymphocytes, developed in the thymus, that circulate in the blood and lymph and regulate the immune system's response to infected or malignant cells. B-Cells produced in the bone marrow. A type of white blood cell that circulates in the blood and lymph and produces antibody upon encountering any antigen that has a molecular arrangement complementary to the antibody.

12 Non-Infectious Disease Non-communicable(infectious) disease is a medical condition or disease, which by definition is non-infectious and non-transmissible among people. Cannot be transferred between people. Examples: Allergies Diabetes Cancer

13 Allergies Allergies occur when your immune system reacts to a foreign substance such as pollen, bee venom or pet dander. Your immune system produces substances known as antibodies. Some of these antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you come into contact with the allergen, your immune system's reaction can inflame your skin, sinuses, airways or digestive system. The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis a potentially life-threatening emergency.

14 Diabetes Diabetes is a group of diseases characterized by high blood glucose levels that result from defects in the body's ability to produce and/or use insulin. Type 1 diabetes is usually diagnosed in children and young adults, and was previously known as juvenile diabetes. In type 1 diabetes, the body does not produce insulin. Type 2 diabetes is the most common form of diabetes. If you have type 2 diabetes your body does not use insulin properly. This is called insulin resistance. Diabetes is a problem with your body that causes blood glucose (sugar) levels to rise higher than normal. This is also called hyperglycemia.

15 Cancer In Cancer, cells divide and grow uncontrollably, forming malignant tumors, and invading nearby parts of the body. The cancer may also spread to more distant parts of the body through the lymphatic system or bloodstream. Not all tumors are cancerous; benign tumors do not invade neighboring tissues and do not spread throughout the body. There are over 200 different known cancers that affect humans.