review question:
list the immune response cells and provide a function for each

Major Histocompatibility Complex (MHC) = proteins on the surface of cells that help the immune system recognize foreign antigens

players:

here's the process all together...

phagocytes may be monocytes, macrophages and neutrophils - white blood cells that engulf pathogens,
foreign material, and dead cells.

 autoimmunity

 the spleen has white pulp where the lymphocytes hang out to identify pathogens and red pulp where macrophages stand by the ready for phagocytosis.

Thyroid
​ Hormone 

review question:
how do natural killer cells destroy infected/cancerous cells?

4. complement

​proteins

  Lymph nodules are areas along the lymphatic vessels
 where there are loads of lymphocytes. Nodes can form clusters...for example: your tonsils (pharyngeal, palatine, lingual) are lymph nodules located in your pharynx. 
​Another example is MALT = mucosa associated lymphoid tissue, lymphoid tissue that protects the epithelial lining of your gut, respiratory tract, urinary system and reproductive systems. 

when an infection is detected, the        immune system triggers the      release of chemicals (pyrogens) which signal the hypothalamus    (the body's thermostat) to raise the        body temperature trying to       create an environment that is less            friendly to the pathogen:
1. inhibits bacterial growth
2. stimulates phagocytosis
3. speeds up tissue repair
4.liver stores more iron so bacteria cant replicate

natural killer cells (NK cells) are white blood cells that destroy infected cells and cancer cells in your body. 

Lymphatic Organs

6. fever

         your immune response

                                  chemical barriers:
1. lysozyme in tears/saliva/mucus
2. stomach acid kills pathogens in digestive system 
3. sweat is acidic - inhibits bacterial growth on the skin 

 T cell maturation/selection

1. 

1​

2

3

4

5

​

6

we just explored
​innate immunity

review question:
what is the role of macrophages in the humoral response?

1. phagocytes

            Immunity
​   and the Lymphatic System  

 Thymus Gland

if the same pathogen/antigen infects the body again, memory B cells will be triggered by that antigen and converted into Plasma B cells which will then produce antibodies to the antigen. 

what's a T cell?

  thoracic duct returns lymph from the majority of your body to the left subclavian vein and left internal jugular vein...
​the right lymphatic duct drains the right head and upper arm/torso into the right subclavian vein.

review question:
what is the purpose of memory B cells? How do they differ from plasma B cells?

artificially acquired active immunity =
antibodies produced when body is exposed to antigen in vaccine

review question:
Describe three reasons your immune system induces fever.

macrophages are professional antigen-presenting cells (APCs) 

3. B cells that have identified the pathogen are confirmed/activated by

helper T cells 

T cells are lymphocytes 
2 types of T cells:

Cytotoxic (killer) T cells
​Helper T cells

2. cytotoxic (killer) T cell binds to this combo and is activated.

  Lymph nodes screen/filter lymph.
lymph is exposed to B cells , T cells and macrophages. As lymph travels the node,
 (think a strainer), 99% of antigens are removed.
​nodes can swell in response to infection.

review question:
how do complement proteins fight an infection?

                    physical barriers:
1. cilia in respiratory tract
2. skin
3. mucous membranes line respiratory,             digestive, reproductive tracts

 now we'll explore 
acquired ​immunity 

cytotoxic
​ T cells

1. infected cell present the antigen of the pathogen on its MHC I

                                                              ​inflammation:
1. damaged cells and immune cells release  chemicals like histamine and cytokines. 
2. these chemicals cause blood vessels to dilate (vasodilation), leading to increased blood flow to the area and increased permeability of the vessels, allowing fluids and white blood cells to leak into the tissues. 
3. this increased blood flow, fluid leakage, and the activity of immune cells results in the the signs of inflammation we know: redness, swelling, heat and pain
4. immune cells try to eliminate the
pathogens/damaged cells and start repairing the tissue.
5. acute inflammation: tissue is repaired.
chronic inflammation: tissue damage and long-term health issues.
more on this later...

review question:
explain the humoral immune response. 

review question:
what is the function of a cytokine?

review question:
What is the MHC?
How do Cytotoxic T cells and Helper T cells differ in the MHC they recognize? 

compared to type 2

btw...
TNF-alpha = Tumor Necrosis Factor alpha = a cytokine 

 T cells are screened in the Thymus Gland to make sure they do not recognize "self" as foreign

                                                immune response cells
1. lymphocytes: 30% of WBCs:
                                   Helper and Killer T cells
                                   B cells produce antibodies
                                   Natural Killer cells (NKs)
2. neutrophils: 65% of WBCs.  fight bacterial and fungal infections.
3. monocytes: large, phagocytic cells
​4. macrophage: phagocytic cells that engulf pathogens/debris.
        derived from monocytes migrating from the bloodstream into tissues. 
5. eosinophils: allergic reactions and fight parasitic infections.
6. basophils: circulating cells release histamine and heparin 
7. mast cells: tissue resident cells release histamine and heparin
8. dendritic cells: phagocytic APC (antigen presenting cell)

with subsequent infections to the same pathogen, antibodies are produced much more quickly

2. natural killer cells
​NKs

5. plasma B cells
produce antibodies against the
specific antigen

 thymus gland shrinks after puberty as the spleen and lymph nodes take over

     2.  humoral/antibody immunity: 
                  Helper T cells stimulate B cells
                     B cells produce antibodies
              Memory B cells remember pathogen

 immune response cells

 lymphatic vessels rely on lymphatic valves to assist in movement of lymph back into circulation

cytotoxic T cells
​(w/CD8+ receptor) recognize antigens presented on 
MHC class I

examples of T cell-mediated
​ autoimmune diseases:

Multiple sclerosis: 
T cells attack the myelin sheath of nerve cells in the brain and spinal cord disrupting the transmission of a nerve impulse 

Type 1 diabetes: 
T cells attack and destroy the insulin-producing cells in the pancreas 

Rheumatoid arthritis: 
T cells contribute to inflammation and damage to joints

Diabetes: Type 1

review question:
what are the two types of immunity.

review question:
describe the inflammatory response.

internal innate defenses

naturally acquired active immunity =
antibodies produced when body is exposed to antigen on pathogen

Growth Hormone 

helper T cells are a past of the antibody response

 T cell maturation is a process where immature T cells, originating from hematopoietic stem cells in the bone marrow, travel to the thymus and mature into functional T cells capable of recognizing specific antigens. 
T cell maturation involves positive and negative selection within the thymus to ensure T
cells recognize both the MHC molecule and
​  "self".

T cells differ by the type of MHC
(Major Histocompatability Complex) they recognize and bind to.

1. macrophages engulf pathogen
and present pathogen's antigen on cell surface using MHC II

        ​ Innate Immunity

review question:
how does a lymph node participate in the immune response?

2. 

cytokines are produced by macrophages, B lymphocytes,
​ T lymphocytes and mast cells

MHC class I          MHC class II

 leucocytes = all white blood cells.
 lymphocytes (B cells, T cells, NK cells) are a specific type of leukocyte. 

review question:
what is the function of a phagocyte?
what is phagocytosis?

Diabetes

naturally acquired passive immunity =
antibodies are acquired via breast milk

review question:
Explain how a fever is triggered. Include cytokines as part of the process.

T cells that the body's own tissues, leading to autoimmune diseases. 

Autoimmune T cells target various self-antigens, leading to organ-specific or systemic autoimmune diseases. 

The immune system normally recognizes and tolerates self-antigens, but in autoimmune diseases, this tolerance breaks down, allowing T cells to attack the body's own tissues. 

2. helper T cells (CD4+) identify antigen presented on
​ MHC class II. 

 Your spleen is responsible for filtering your blood by removing old or damaged RBCs, storing iron from recycled RBCS, and triggering immune responses by B/T cells circulating in your blood. 

helper
​ T cells and B cells

    Acquired Immunity

            lymph drains back into circulation via the thoracic duct and lymphatic duct

 innate vs adaptive
​immunity

 lymph nodes/nodules

 spleen

3. interferons...

a type of cytokine

review question:
what are 3
​functions of the Lymphatic System?

 immune response
​participants

complement proteins are released when the complement system is activated.
this occurs in response to infection or tissue damage. inactive proteins are activated via through a cascade of enzymatic reactions which trigger a chain reaction where one protein activates the next.,

 antibodies are
Y-shaped proteins that bind to specific antigens

artificially acquired passive immunity =
antibodies are acquired via antibody injection

review question:
describe 3 ways antibodies prevent infection by pathogens.

4. B cells
​ are converted to
plasma B cells and memory B cells

review question:
Explain the process of Cell Mediated Immunity. 

external innate defenses

6. memory B cells
provide long-lasting immunity against previously encountered pathogens by producing antibodies if the same antigen is present

cytotoxic T cells
​are part of the cell mediated response

3. cytotoxic T cell secretes perforin and granzyme.

4. cell is degraded and triggers apoptosis

helper T cells (w/CD4+ receptor) recognize antigens presented on
​ MHC class II. 

interferons are a type of cytokine
that "interferes" with viruses' ability to infect and multiply. . 

review question:
describe the 3 physical and 3 chemical barriers of our external innate defense system

how do antibodies fight off the pathogen?

 1. cell mediated immunity:
​  cytotoxic T cells destroy cells infected with pathogen

you have acquired

​this immunity 

5. inflammation