Unit 3 – Dynamic Equilibrium
Section 6- Immune System
The ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells.
The system in the body responsible for maintaining homeostasis by recognizing harmful from nonharmful organisms and produces an appropriate response.
Viruses, bacteria or other living thing that causes disease/immune response.
Toxins that pathogens produce that cause harm to an organism.
Blood - White Blood Cells in particular.
Thymus Gland – Produces T Lymphocytes
Bone Marrow – Produces B Lymphocytes
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
Second Line of Defense – Nonspecific Immune Response
These are defenses the body uses no matter what the invader may be. These defenses include:
Phagocytosis – done by Macrophages
Natural Cell Killers
Inflammation - caused by release of Histamine from leukocytes
Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins.
Macrophage: A phagocytic cell found in the liver, spleen, brain and lungs. Travels
to all areas of the body to find and eat pathogens.
This is a specific response to a specific pathogen/antigen.
The response involves the creation of Antibodies.
Third Line of Defense – Specific Immune Response
Y-shaped protein molecule.
Made up of variable and constant regions.
Made up of Heavy and Light chains.
Produced by B-Lymphocytes
Function: Recognize antigens, bind to and deactivate them.