BIO118 Unit 4

What are the 3 hypotheses regarding autoimmune diseases? How can pathogens trigger autoimmune disease? How might worm parasites help prevent autoimmunity?

1. Antigen exposure 2. Microchimerism -- The antibodies past down to you through your mom when you are in the womb or breast feeding. 3. hygiene hypothesis - not good to be clean all the time ???

Trace the order of peak use of these cells (some fall into similar time slots): basophils/mast cells, neutrophils, NK cells, macrophages, killer T cells, helper T cells, plasma B cells, antibody production, & suppressor T cells.

1. Mast cell Dendritic cell and neutrophils 2. NK cells 3. Macrophages, killer T-cells and Helper T-cells 4. Plasma B cells 5. Antibody production 6. Suppressor T cells.

How do you fight off a large pathogen? A small pathogen? One inside cells? One outside cells?

A large once uses granulocytes to fight large pathogens because they can release degranulation which damages the tissue. Macrophage eats it presents it and then t-cells come and destroy it. Outside of the cell is bacteria. In order to fight off bacteria Phagocyte eats the bacteria and shows it to the T-helper cell which than signals the B cell which covers the bacteria in antibodies. Inside the cell is the virus. An infected cell releases some of what it is infected with signaling that it is sick, the phagocyte will come collect it and present it to the T-helper cell which signals the T-cytotxic cell which tells the infected cell to die. Apoptosis (cell suicide)

What is lymph & where is it found? Describe the composition of lymph. Describe the structure of lymph capillaries. Why are their walls so "permeable"? Why do lymph vessels contain 1-way valves?

A term to describe interstitial fluid (water glucose and salts) once it is in a persons body. Lymph capillaries or lymphatic capillaries are tiny, thin-walled vessels located in the spaces between cells (except in the central nervous system and non-vascular tissues) which serve to drain and process extra-cellular fluid The endothelial cells forming the walls of the lymph capillaries are not tightly packed together allowing things to move in and out easier. lymphatic vessels contain a one way valve in order to prevent back flow and leakage. It is being brought back to the heart so that it can reenter the blood stream.

Where is the thymus located? What are 2 of its major functions? Graph the size of the thymus from birth to old age. Explain why the thymus is large when we are young. What happens to the disease fighting potential of our T cells as we get old?

Above the heart. It is were T-cells are trained and developed to fight off pathogens. It decreases as you age. Because our immune system isn't developed yet so it produces more t-cells in order to build our immune system and "memory. As we age t-cells become less abundant so our disease fighting potential is decreased.

Describe the reticular fibers that support a nodule.

Connective tissue that form "meshwork" to support the nodule.

Describe the structure of lymphatic lobules/nodules.

Contain many white blood cells Leukocytes and reticular fibers for structural support.

Describe 4 major "themes"that help explain how the immune system fights infections.

Diffuse: White blood cells and other immunity cells are able to easily diffuse through membranes in out body to fight foreign invaders. Duplication: Cells are duplicated in order to be better prepared for a foreign object the second time around. Positive feedback: Speeds up and amplifies the reaction in order to get rid of the bacteria or virus. Swelling: The tissue around a foreign body swells in order to keep it there and not let it spread throughout the body.

How can diet & exercise affect the immune system? What can you do to "optimize"your immune responses to infections?

Having moderate regular exercise is good for the immune system. High intense exercise puts you more at risk for infection/disease. Having a healthy diet will also help. When you are a child you should be exposed to everything you shouldn't live in a bubble because that is when your body is building the immune system. Also regular exercise and healthy diet.

What are the advantages of having lymph nodes "filtering' lymph? Describe the afferent & efferent vessels of a lymph node. Why do lymph nodes swell up during an infection?

Help get rid of the pathogen, more opportunities to spot a pathogen. Afferent vessels are going into the lymph node and efferent vessels are going out of the lymph node to the rest of the body. They swell because a pathogen is detected and that increases the number of white blood cells causes the lymph node to swell. Restricts blood flow causing edema.

How does the removal of the spleen affect a person's health?

Higher risk of infections because lowering the filtration of pathogens.

Where are your tonsils located? Why are tonsils part of the "front-line"defenses of the digestive & respiratory system? What can happen if tonsils swell up?

In the back of your throat. Because it is the first thing pathogens come in contact with through the mouth Trouble breathing infection.

Compare and contrast innate vs adaptive immunity. How are they different, how are they similar?

Innate system tells the adaptive system when it is needed and what it needs to attack. Innate is always in your body and the adaptive is formed when it is being introduced to a new foreign body.

When is innate immunity active?

It is active all the time

Describe the structure & location of the spleen. What is red & white pulp? What are 4 of the major functions of the spleen?

It is soft and spongy not strong easily damaged. Has red (blood) and white pulp (lymphatic nodules). Stores blood for emergencies, filters pathogens out of blood, phagocytes removes old RBC's.

What are the major cells of the immune response?

Mast cell, Natural killer cells, macrophages, T-cells and B-cells, Neutrophil.

What are mast cells? Where do we find them. What is their role in the immune response?

Mast cells are the cells that release histamine which attracts other cells to come and help. They are found in the Connective tissue of the body (lungs skin and lining of the stomach). The mast cell is a granulocyte (Full of vesicles) Example of positive feedback.

Explain the role of positive & negative feedback in that immune response

Positive feedback: Allows for cells to be able to replicate faster in order to fight a foreign body faster and more efficiently. Negative feedback:

Describe 2 major functions of the lymphatic circulation. What is the benefit of having a slow fluid flow? Define edema & 2 common causes of it. How are tissues damaged?

Removes pathogens and transports liquid out of extracellular tissue. Less likely to have a blood clot, and so that the lymph organs can easily pick out the pathogen since it is slow moving. Edema is having excess fluid in a cavity or tissue of the body. Two common causes are allergies and having to much pressure on it at a time. Tissues are damaged by edema because when the tissue is swollen it is cutting off the circulation to the surrounding tissue causing cell death.

What is an MHC? How do we inherit our MHCs? Explain how MCH diversity might play into mate choice.

Self cells have MHC and Non-self lack MHC. We get some from each parent. Having different variety of MHC improves our immune system response and in turn improves our survival rate.

Describe the physical barriers to infection. How do they work? How do pathogens protect themselves against these barriers? What is inflammation? How is it helpful in the immune response?

Skin provides a physical barrier to pathogens, and mucous membranes. ? They might blend in with our normal cells and mimic them. Inflammation is the swelling of tissue. It helps keep the pathogen from spreading throughout the body.

How do specific & non-specific immune systems communicate with each other to fight infections? (Think about some of the positive feedback loops.) What is the role of suppressor T cells?

Specific is the adaptive and non-specific is the innate. So the innate has to tell the specific what to go attack and how. Suppressor T-cells stop the immune response.

What is the hierarchy of the adaptive immune system? Where do T cells come from? When are naïve T cells most abundant? When is our immune system the "best"?

T--helper, B or T cytotoxic and then either antibodies or Cell suicide. T-cells originate in bone marrow as hemocytoblasts and then turn to lymphoblasts and then they go to the thymus where they become trained t-cells. Naive T-cells are most abundant when we are younger. It is the best when we are young because it is still growing and adapting.

Explain this pathway: fluid leaks out of a blood capillary -> extracellular fluid moves into a lymph capillary -> lymph fluid moves toward the heart (from any part of the body). What moves fluid once it is in a lymph vessel? Why is the volume of lymph moved so small?

The pressure gradient moves the fluid once it is in a lymph vessel. There is no pumping organ to move the lymph so it has to move on its own.

Describe the stages of an immune response.

The stages of the immune system are identify signal and destroy.

What are the risks from infection or sickle cell disease to a spleen?

Too many red blood cells to be broken down leads to less efficiency and break down of the spleen. Difficult to repair once this happens.

When is adaptive immunity active?

When Pathogens are present and when the innate system fails.

What is an allergy? Why does out body sometimes attack itself (autoimmunity)? What would happen if the immune response was too small? Or too big? How does the immune response stop (when does the body know an infection is over?)

When your innate immune system is too broad or not specific enough it can attack something that is non-dangerous and triggers a too aggressive response. If the innate immune system is too broad it won't know what is self and non-self. If the immune response is too small it might not get rid of the pathogens or foreign bodies. If the immune response is to big your immune system will attack itself. Causing allergy or autoimmune disease. T-reg or suppressor t cells tell it when to stop.