1. Unit 7: Infectious Diseases
Immune System
Unit 7: Infectious Diseases

2. Immune System
System of chemicals, white blood cells, and tissues that protect the body against pathogens
Aided by lymphatic system

3. Lymphatic System
Returns fluids leaked from the blood back to the blood
Contains many different types of white blood cells
Organs include: lymph nodes, spleen, thymus, tonsils, and lymphoid tissue in digestive and respiratory tracts
Lymph nodes are like filters for pathogens and activates immune response against an antigen

4. Lymph Node

5. T cells
Helper T-cells (Th) recognize the virus and begin to divide over and over. Thus producing new T cells that also recognize the virus.
Suppressor T-cells (TS) slow down activity of B and T cells once the antigen has been destroyed
Memory T-cells cause quicker response if infection with same pathogen occurs again
Helper T cell signaling B cell to differentiate into plasma cell and
produce antibodies

6. Active vs. Passive Immunity
Active - a person’s immune system forms memory cells against an antigen (either through contracting an illness or through a vaccine)
Passive - a person receives antibodies against an antigen but does not form memory cells