1. Agenda 2/12 Immunity notes Immune system storyboards
Homework: study for cumulative quiz (digestion, circulation, respiration, immunity)
Turn in: Video notes

2. Immune System
Function: to prevent bacteria, viruses, and other harmful things from damaging our bodies
The majority of pathogens we encounter don’t make us sick
Skin and mucous membranes blocks the majority of them
If that doesn’t work, we have many immune system cells that destroy pathogens
If that doesn’t work, we have medications that can assist our immune system

3. Primary Defense: Skin and mucous membranes
Skin: physically blocks pathogens from entering
Sweat has enzymes that damage bacterial cell walls
You skin also has millions of microbes living on it which out compete harmful pathogens for space
No known microbe can penetrate through the skin
Mucous Membranes
Trachea, nasal passages, urethra, vagina all have mucous membranes with cells that produce mucus
Mucus traps pathogens from entering the body
Cilia is also present in some of these locations which helps trap and expel pathogens

4. Blood Clotting
If you get a cut, the skin barrier is broken and your blood stream is exposed
This gives pathogens a chance to get into your blood stream (bad)
Our bodies are able to seal the cut very quickly
1. Damaged blood vessels release chemicals (clotting factors)
2. Prothrombin (a protein) is converted into thrombin (an enzyme)
3. Thrombin (enzyme) converts fibrinogen (a protein) into fibrin which forms a barrier around the damaged blood vessel
4. Chemicals released also attract platelets which stick to damaged blood vessels

5. Blood Clotting Flow Chart

6. Secondary Defense- White Blood Cells
White blood cells can destroy pathogens that get past the first line of defense
Two types of responses
Nonspecific- Macrophages
Specific- antibodies, t-cells

7. Macrophages
Macrophages are phagocytic cells that can engulf (eat) pathogens that it encounters in the blood stream
Macrophages are able to recognize ‘self’ vs. ‘non-self’ and will only destroy ‘non-self’ pathogens
They can detect normal and abnormal proteins on the surfaces of cells
Phagocytes have a lot of lysosomes with damaging enzymes that will kill the pathogen once it is engulfed

8. Antibodies
Antibodies are protein molecules that are SPECIFIC to one pathogen
Produced by B cells (plasma cells)
Each type of plasma cell only produces one type of antibody
Have a lot of endoplasmic reticulum/ribosomes to produce a large amount of protein

9. Activation of B Cells and Antibody Production
1. A macrophage carries a piece of the pathogen (antigen) to lymph nodes to find a B cell that ‘matches’
The b cell receptor must be able to bind to the antibody to make an antibody that will work against the pathogen
2. Once a match is found, the B cell will be activated and will clone itself to make many copies
3. All those B cells will produce antibodies SPECIFIC to that pathogen
4. Antibodies circulate blood stream, bind to pathogen, and make it easier for your immune system to get rid of them
5. Some of those activated B cells remain in your body as memory cells, so antibodies are produced much faster if you are infected a 2nd time

10. Antibody Production

11. HIV (human immunodeficiency virus)
HIV is a virus that infected helper T cells
As helper T-cells are infected, you immune system kills them off
This means, you have less cells to activate B cells and T cells to kill the virus
HIV has a long latent period
That means you can have the virus for a very long time, transmit it, but not show any symptoms or know you have it

12. AIDS (acquired immunodeficiency syndrome)
AIDS is the disease caused by HIV
AIDS is present when you begin showing symptoms of a weakened immune system (immunocompromised)
AIDS patients get opportunistic infections
Many treatments available in developed countries

13. Antibiotics
Antibiotics work against PROKARYOTIC cells only (not viruses)
They target unique structures found in only prokaryotic cells, so they do not damage our own cells
Cell wall, prokaryotic ribosomes
They will destroy bacteria cells
Viruses have no metabolism, and nothing to target so antibiotics will do nothing against a viral infection!!!
Bacteria resistance is a growing problem

14. Immune System Story Boards
You will create a story board for the sequence of events that occur during an immune system response.
1- A pathogen is blocked by skin and mucous membranes
2- That pathogen enters through an open cut (as your body is building a clot)
3- Some of that pathogen is destroyed by phagocytic cells, some escape
4- Some of that pathogen is destroyed by antibodies, some escape
5- Antibiotics are taken to destroy the remaining bacteria cells
Include: a picture, 4-5 sentence description, and key words for each step
Key words to include: skin, mucus, cilia, macrophage, lysosome, plasma cell, helper t-cell, antibodies, thrombin, prothrombin, fibrinogen, platelets, fibrin, specific, non-specific, memory B cells