1. The Immune System
Packet #22
Chapter #31

2. Body responds to pathogen
Introduction
The immune system includes all of the structures and processes that provide a defense against potential pathogens (disease causing agents).
Immunity, the ability of an organism to resist disease, are in two forms
Passive Immunity
Immunity passed from mother to child
Via genes
There is no immune response
Active Immunity
The body produces a response to a particular pathogen.
Immunity
Passive
Mother to Child
Genes
Active
Body responds to pathogen
Response to Pathogen

3. Human Body Defense Mechanisms
Active Immunity

4. Human Body Defense Systems
Defense Mechanisms
Lymphocytes
Non-Specific
Rapid
Specific
Several Days
Defense Mechanisms
Non-Specific
Defense is a rapid response to a wide range of pathogens
Specific
Takes several days to mount
Delivered by the Immune System
Lymphocytes
Saturday, April 22, 2017

5. Lymphocytes

6. Introduction Lymphocytes T Cells Thymus-dependent B Cells
Bursa of Fabricius
Lymphocytes (a type of white blood cell) are derived from unspecialized stem cells in the bone marrow.
Large numbers of lymphocytes are found in the thymus, spleen and lymph nodes.
There are two types of lymphocytes
T cells
Thymus-dependent lymphocytes
B cells
Derived from the discovery of B cells in the bursa of Fabricius
Mammals do not have this organ
Which type of stem cells should be found in the bone marrow?

7. B Cells
Secrete antibodies (proteins) into the blood and lymph in order to inactivate pathogens.
Combat bacterial infections and some viral infections
Because blood and lymph are body fluids (humors), and since they release antibodies, the B cells are said to provide humeral immunity (antibody-mediated immunity)
Types of B cells include
Memory B cells
Plasma cells

8. T Cells
Attack host cells that have become infected with viruses or fungi, transplanted human cells and/or cancerous cells.
These cells do not secrete antibodies.
Must be in close proximity to destroy the infected cell.
Provide cell-mediated immunity.
Cell-mediated immunity involves the use of T cells.
Types of T cells
Killer T Cells
AKA Cytotoxic T cells
Helper T Cells
Suppressor T Cells

9. Humoral Immuntiy vs. Cell-Mediated Immunity
See Pages 764 & 765 in textbook.

10. Specific Mechanisms

11. Specific Defense Mechanisms
Antigens
Molecules (proteins), found on the surface of cells, that stimulate the production of specific antibodies.
The ID card.
Natural
Foreign
Haptens
Small organic molecules that can become antigens if they are bond to proteins.
Immunoassays*
Specific Defense Mechanisms
Antigens
Haptens
Immunoassays

12. Non-Specific Mechanisms/Barriers
*Happens the same way for each pathogen?

13. Non-Specific Defense Mechanisms
Phagocytosis
Neutrophils
Macrophages
Phagocytes
Fever
Interferons
Messengers
Phagocytosis
Engulfing of pathogens
Neutrophils
Macrophages
Phagocytes
Fever
Produced by cytokines
High fevers are dangerous however fevers aid in the destruction of pathogens
Interferons
Polypeptides that act as messengers that protect other cells in the vicinity from viral infection.

14. Introduction
The non-specific defense systems utilizes different “defensive lines” in order to be successful.
{*Similar to having an alarm system for the house but there are specific sensors, at the doors and windows for example, that trigger the alarm system.}
Similar to having an alarm system for the house but there are specific sensors, at the doors and windows for example, that trigger the alarm system.

15. The Immune System Non-Specific Defense System Barriers/Mechanisms The First Line of Defense
The Skin
Mucous Membranes
Cilia
Lines the lungs
Gastric Juice
In the stomach
Kills most microbes
Saturday, April 22, 2017

16. The Immune System Non-Specific Defense Barriers/Mechanisms The Second Line of Defense
Inflammatory Response
Redness; swelling; heat; pain
Lymphocytes are activated.
Fever is developed.
Saturday, April 22, 2017

17. The Immune System Non-Specific Barriers/Mechanisms The Third Line of Defense
Consists of mechanisms and agents that target specific antigens
Via the use of lymphocytes.
Saturday, April 22, 2017

18. Over Active Immune System

19. Allergies
An allergy is an oversensitivity to a normally harmless antigen.
Harmless antigens, that cause the over-the-top response, are known as allergens.
Food
Peanuts
Airborne
Pollen
Pet dander
Mold
Chemical
Penicillin
Jewelry metals

20. Review