210 likes | 488 Views
Warm Up:. What is homeostasis?. Recall: Homeostasis is the. regulation of an organism’s internal environment to maintain conditions needed for life. When homeostasis is disrupted disease can occur. Immune System. What is a pathogen?. Cause of infectious disease. Types of pathogens. Virus
E N D
Warm Up: • What is homeostasis?
Recall: Homeostasis is the regulation of an organism’s internal environment to maintain conditions needed for life When homeostasis is disrupted disease can occur
What is a pathogen? • Cause of infectious disease
Types of pathogens • Virus • Bacteria • Fungus • Parasites • Protists These are microbes: microscopic organisms
What is Cancer? • Characterized by abnormal and uncontrolled cell growth
Why is cancer an example of the body not maintaining homeostasis? • Normally the body controls beginning and end of the cell cycle • If control is lost, abnormal or uncontrolled cell growth can lead to tumors
The Immune System • Mechanisms in an organism that protects body against disease
Antigen Substance foreign to the body that causes an immune response
Body’s 1st Line of Defenses Barriers -Skin barrier -Chemical barriers (saliva, tears, nasal secretions) -Hydrochloric acid in stomach
Body’s 2nd Line of Defenses Non-Specific Response -White blood cell use engulf pathogen
Body’s 3rd Line of Defenses Specific Response involves lymphatic system which filters lymph and blood destroying foreign microorganisms Includes B cell and T cell response
Antibodies • Proteins produced by B lymphocytes (B cells) that specifically react with a foreign antigen
T cells Add this to your notes • Helper T cells activate antibody production in B cells and activates cytotoxic T cells • Cytotoxic T cells destroy pathogens and release chemicals
White blood cells • Some WBCs mark pathogens for destruction while others engulf microbes during an immune response • And yet others produce antibodies
Why do people rarely get the same disease twice? • Memory cells reduce the likelihood of developing the same disease twice
Vaccine • Dead or weakened form of a virus used to stimulate an immune response
Immunity • 2 Types • Inborn Immunity: immunity to disease at birth • Acquired Immunity: develops during lifetime
Acquired Immunity Add this to your notes
Add this to your notes Allergies • Reactions to usually harmless environmental antigens • Mast cells release histamines • Causes a localized inflammatory response • Swollen, itchy eyes, stuffy nose, sneezing • Pollen, dust, dust mites, food
AIDS • Human Immunodeficiency Virus • Attacks white blood cells (CD4) • Weakens patient’s immune system