Mr. Mah Living Environment Lecture 12

 Give THREE examples of vectors:  FliesTicks  MosquitoesSquirrels  RatsFleas  What are the 4 types of pathogens?  VirusesParasites  BacteriaFungi

 SWBAT explain how the immune system responds to invasion of pathogens.  SWBAT identify all the functions of white blood cells and lymphatic system

 = disease causing micro-organisms ▪ bacteria ▪ virus ▪ fungi ▪ parasites

 Pathogens  Viruses, bacteria or other living thing that causes disease/immune response.  Antigens  Toxins that pathogens produce that cause harm to an organism.

 The ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells.  Immune System  Responsible for maintaining homeostasis by recognizing harmful organisms and produces an appropriate response.

 Thymus – glandular organ near the heart – where T cells learn their jobs  Bone marrow – blood-producing tissue located inside certain bones  blood stem cells give rise to all of the different types of blood cells  Spleen – serves as a filter for the blood  removes old and damaged red blood cells  removes infectious agents and uses them to activate cells called lymphocytes  Lymph nodes – small organs that filter out dead cells, antigens, and other “stuff”  Lymphatic vessels – collect fluid (lymph) that has “leaked” out from the blood into the tissues and returns it to circulation

skin prevents entry tears antibacterial enzymes saliva antibacterial enzymes stomach acid low pH kills harmful microbes mucus linings traps dirt and microbes “good” gut bacteria out compete bad bacteria

The Body’s THREE lines of Defense First Line of Defense – The Skin Provides Physical and Chemical barriers ▪ Physical – hard to penetrate, made of indigestible keratin ▪ Chemical – tears, sweat

10  Physical  skin  hair  mucous  Chemical  sweat  tears  saliva  stomach acid  urine

These are defenses the body uses no matter what the invader may be. These defenses include:  Phagocytosis – done by Macrophages  Natural Killer Cell  Inflammation - caused by release of Histamine from leukocytes  Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins.

 Involves white blood cells (called Leukocytes)  Non-specific response  invading pathogens are targeted by macrophages  Specific response  lymphocytes produce chemicals called antibodies that target specific pathogens

13 nonspecific - the same response works against many pathogens this type of response is the same no matter how often it is triggered the types of cells involved are macrophages, neutrophils, natural killer cells, and mast cells

14  Macrophages engulf pathogens and dead cell remains  Neutrophils release chemicals that kill nearby bacteria pus = neutrophils, tissue cells and dead pathogens

An accumulation of : -  dead phagocytes  destroyed bacteria  dead cells

 This is a specific response to a specific pathogen/antigen.  The response involves the creation of Antibodies.

 Immunity-state of being resistant or not susceptible to a specific disease  Acquired immunity-any form of immunity NOT present at birth and obtained during life

18 Step 1. Circulation to the site increases  tissue warm, red and swollen Step 2. WBCs leak into tissues  phagocytes engulf and destroy bacteria chemical and cell response to injury or localized infection eliminates the source of infection promotes wound healing

20 POSITIVE  indicate a reaction to infection  stimulate phagocytosis  slow bacterial growth  increases body temperature beyond the tolerance of some bacteria  decreases blood iron levels NEGATIVE  extreme heat  enzyme breakdown and interruption of normal biochemical reactions > 39° C (103°F) is dangerous > 41°C (105°F) could be fatal and requires medical attention Fevers have both positive and negative effects on infection and bodily functions

 Primary Immune Response  This is a response to an invader the First time the invader infects the body. ▪ No measurable immune response for first few days. ▪ Next 10 – 15 days antibody production grows steadily  Secondary Immune Response  A more rapid response to an invader the 2 nd time it invades the body. ▪ Antibody production increases dramatically and in a much shorter time period..

1. Active Immunity This is immunity where the body is “actively” producing antibodies to fight infection. Ex: You have a throat infection and you are actively creating antibodies to fight it. Vaccination: An injection of a weakened strain of an infectious microbe (pathogen) that causes the body to undergo active immunity (produce antibodies). 2. Passive Immunity This is immunity where antibodies are given to a person from the blood of another person or animal. This immunity only lasts for a short period of time. ex: Breastfeeding mothers pass antibodies to their children through the milk.