The Immune System PDF

The Immune System What is Disease? Disruption of homeostasis Can be caused by a variety of pathogens Failure to respond to this disruption causes disease, and possibly death Homeostasis An organisms environment is constantly changing Homeostasis is the way biological systems maintain stability Sel...

The Immune System What is Disease? Disruption of homeostasis Can be caused by a variety of pathogens Failure to respond to this disruption causes disease, and possibly death Homeostasis An organisms environment is constantly changing Homeostasis is the way biological systems maintain stability Self regulation of processes that responds to changes, such as temperature, or blood sugar levels ◦ Failure to respond What Causes Disease? PATHOGENS! ◦ Pathogens are disease causing organisms Pathogens include ◦ Viruses: HIV, common cold, the flu ◦ Bacteria: strep throat, goof poisoning ◦ Fungus: athletes foot, the zombies from the Last of Us ◦ Parasites: Tapeworms ◦ Cancer cells ◦ This is a special case where they are host cells, however, mutations have occurred and the cells replicate uncontrollably and avoid cell death(apoptosis) instead of being destroyed by the immune system What is the function of the Immune System To protect against disease It is very important in maintaining homeostasis Used once the body is invaded by foreign substances How? Innate Immunity ◦ Non-specific ◦ Includes some cells, as well as mechanical and chemical barriers ◦ Things like skin, saliva, mucous, stomach acid ◦ Also includes fever and inflammation Adaptive ◦ Highly specific, even small changes in structure will not be recognized ◦ Uses highly specific antibodies and antigen binding cells ◦ Utilizes Leukocytes or white blood cells (WBCs) and antibodies Antibodies Y shaped, highly specific proteins that bind to antigens Created by types of WBCs Aid in immune response Antigens Antigens are proteins on the surface of cells Activate immune response by binding to immune cells Types of White Blood Cells Monocytes: Macrophages Leukocytes: T and B cells ◦ Function in adaptive immune response Other types of WBCs also work with the innate immune response Macrophages Monocyte Aid in both innate and adaptive immunity Engulf and destroy pathogens Aid in adaptive immunity by recruiting other WBCs Helper T Cells Assist in activating other types of WBCs Interacts with antigens presented on the surface of macrophages After binding to an antigen, these can then active killer T cells and B cells Killer(Cytotoxic) T Cells Activated by helper T cells Use chemicals that it excretes to destroy pathogens and infected host cells This helps to stop the spread of the pathogen ◦ Many viruses infect host cells and hijack their cellular processes to make them replicate the viral proteins instead of their own B Cells These cells are activated by Helper T cells After activation, they differentiate into memory B cells and plasma cells ◦ Memory B cells keep the antigen on their membrane, while plasma cells secrete antibodies If a helper T cell does not give the B cell an antigen, it will not differentiate, and will undergo cell death (apoptosis) Memory Cells Remain following infection to store “memory” These “memories” assist in creating a quick immune response when exposed to the same antigen Antibodies are created and bind to the antigen, quickly dispatching the pathogen before disease occurs Cell Mediated Immunity Uses T cells to identify and destroy Helper T cells identify antigens and active other immune cells This activation activated the killer(cytotoxic) T cells, which then work to destroy pathogens and infected host cells Humeral Immunity Antibody mediated immunity Antibodies are created and released by B(plasma) cells ◦ These antibodies are generated during a previous exposure to an antigen You can also gain immunity through antibodies from someone else that has survived the disease ◦ Think back to the smallpox in India from the video we watched This type of immunity is VERY specific Vaccines Vaccines are used to elicit the same immune response as infection Vaccines introduce a weak or dead, entire or piece of, a pathogen to generate an immune response ◦ This uses adaptive immunity, and leaves you with memory t cells to prevent later infection by the same pathogen ◦ Since the pathogen is weak or inactive, the risk of disease and actual infection by the pathogen is slim to none Issues with immune response Allergies: a result of the body responding to allergens and creating an unnecessary immune response ◦ Body releases histamines which cause allergic reactions such as increased mucus, rashes or swelling Self Attack: when the immune system attacks “self” cells, thinking they are a threat ◦ This causes diseases such as diabetes and arthritis Organ Transplant: organs may have antigens foreign to the new host, creating an immune response ◦ This would lead to organ rejection. Immunosuppressants are used to mediate this Weaken Immune Systems Many factors can cause a weakened immune system ◦ Stress ◦ Fatigue ◦ Other disease HIV attacks immune cells, weakening the bodies ability to respond to threats ◦ It replicated inside and kills your T cells AIDS occurs when certain diseases are contracted that normal healthy people do not get infected by, because of the compromised immune system Key Takeaways Disease is a disruption of homeostasis The immune system functions to fight disease caused by pathogens ◦ This includes viruses, bacteria, parasites and fungus Vaccines can help to fight against disease by strengthening the immune system by using weakened pathogens White blood cells function to: engulf pathogens, produce antibodies to mark them for destruction and leave “memory” to fight repeat infection by specific pathogens Issues with the immune response can cause allergies, diseases like diabetes The immune system can be weakened by things like HIV, or fatigue, poor nutrition genetic Cancer is caused by mutations in cells, and if not recognized and destroyed by the immune system, undergo unregulated cell division Questions!!! What is the function of vaccines and how do they work? What type of cells aid in immune response? What occurs when cells divide uncontrollably,? When infected by a virus or bacteria, what molecule would be at increased levels in the blood? What do immune cells bind to in order to elicit an immune response?