1. Defense Against Infectious Diseases
Immune System

2. The Lymphatic System Three basic functions
Maintains body fluids at a constant level
Absorbs fats from the digestive tract
Helps body defend itself against disease

3. Immune System
Innate Immune System – defense mechanisms that your body uses to protect you from MANY different types of pathogens
Skin – the first line of defense; also home to lots microorganisms that inhibit the multiplication of pathogens
Secretions – mucus, sweat, tears, saliva
Secretions trap or kill off pathogens

4. If a pathogen gets by the skin and secretions….
Phagocytes – a white blood cell (WBC) that ingests and destroys pathogens by surrounding and engulfing them
When a pathogen is present, phagocytes migrate out of your blood capillaries to the infected areas

5. Macrophage – one type of phagocyte
After a macrophage engulfs large numbers of microbes and damaged tissue, they eventually die
The infected area will contain a collection of dead WBCs and various body fluids = pus (eeeeewwwww!! But now you know what it is!)

6. Inflammation of body tissues
Inflammation (redness, swelling, pain and heat) occurs when body tissues are damaged by pathogens (can also be a reaction to ANY type of injury)
Injured cells release histamine – which is a chemical alarm system, causes blood vessels to dilate and inflammation to happen

7. Adaptive Immune System
Immunity – defense against a specific pathogen by building up a resistance to it
Antigen –foreign substances (proteins, bacteria, viruses, etc.) that stimulate the production of antibodies in the blood
Antibody – proteins produced in reaction to foreign substances (antigens) antibodies are specific to an antigen

8. Vaccinations
Vaccine – a mixture of a harmless component of a disease-causing microbe, a dead or weakened pathogen or part of a microbe
Pathogen = microbe
A vaccine stimulates the immune system to increase defenses against the antigen
Body builds up antibodies and can react quickly if exposed to the pathogen (antigen) again