Chapter 8- Immune System Flashcards
Leukocytes
White blood cells
Spleens role in immunity
Location of blood storage and activation of B cells which turn into plasma cells that produce antibodies.
What do you call a cell that has just left the bone marrow?
Mature but naive (has not yet been exposed to an antigen)
Where do T cells mature? Where do B cells mature?
T cells mature in the thymus
B cells mature in the spleen
Lymph nodes
Provide a place for immune cells to communicate and mount an attack,
Another site of B cell activation
What are the two types of leukocytes?
Granulocytes and Agranulocytes
What is the significance of the granules on granulocytes?
These granules contain toxic enzymes and chemicals that can be released by exocytosis and are effective against bacterial fungal and parasitic pathogens.
What are the three types of granulocytes?
Neutrophils, eosinophils, basophils
What are the types of agranulocytes?
Monocytes and lymphocytes
Monocyte vs macrophage?
A monocyte is a phagocytic cell in the bloodstream… when a monocyte moves into tissue it is considered a macrophage (examples include microglia in the central nervous system, Langerhans cells in the skin and osteoclast in the bone)
Humoral immunity and cell mediated immunity are driven by which types of cells?
Humoral immunity is driven by B cells.
Cell mediated immunity is driven by T cells.
What anti-bacterial enzymes are found on the skin that help protect the body?
Defensins
What nonspecific bacterial enzyme is secreted in tears and saliva?
lysozyme
How do complement proteins aid in the innate immune system?
They punch holes in the cell walls of bacteria making them osmotically unstable.
Classical pathway- requires the binding of an antibody to a pathogen
Alternative pathway- does not require antibodies
Interferons
A protein that prevents viral replication and dispersion by causing production of viral and cellular proteins,
decreasing the permeability of the cells making it harder for a virus to infect them,
up-regulating MHC class one and class two molecules allowing better detection of the infected cell by the immune system.
Responsible for flulike symptoms that occur during a viral infection.
First line of defense in the innate immune system.
Include the compliment system, interferons, the skin, the G.I. tract, eyes and nose
Macrophage
A part of the innate immune system.
Fight against bacteria in cell tissue by…
- Phagocytize is the invader through endocytosis.
- Digest invader using enzymes.
- Presents a little piece of the invader to the other cells using a protein called MHC (major histocompatibility complex) 
Release cytokines chemical substances that stimulate information and recruit additional means out of the area
MHC
Binds to a pathogenic peptide a.k.a. antigen carries it to the cell surface where I can be recognized by the cells of the adaptive immune system
Cytokines
Chemical substances that stimulate inflammation and recruit additional immune cells to the area
Antigen
A substance (usually a pathogenic proteins) they can be targeted by an antibody
MHC I vs MHC II molecules
MHC I – Endogenous binds to antigens that come from inside the cell. All nucleated cells in the body display MHC class one molecules.
MHC II- Exogenous displayed by professional antigen presenting cells like macrophages. Pics of pathogens from the environment, processes them and presents them on MHC II
What are the main cells in the innate immune system?
Macrophages, mast cells, granulocytes, dendritic cells, natural killer cells
Macrophage
Recognize invaders such as bacteria viruses fungi or parasites. They engulf and consume pathogens.
Release cytokines that recruit the right type of immune cell.
Natural killer cells
Recognize down regulation of MHC and induce apoptosis in virally infected cells. Kill with no questions asked.
Granulocytes (examples and function)
Ex: eosinophil, neutrophil, basophil
Phagocytic cells that target bacteria.
Neutrophils
Type of granulocyte. Phagocytic cell.
Follows bacteria using chemotaxis.
Can detect bacteria that have been opsonized (marked with an antibody from a B cell). Other cells can attack the bacteria
Dead neutrophils = pus
Eosinophils
Type of granulocyte. Primarily involved with allergic reactions and parasitic infections.
Release large amounts of histamine (an inflammatory mediator). Resulting in vasodilation allowing additional immune cells to move out of the bloodstream and into the tissue.

Basophils/Mast Cells
Type of granulocytes
Involved in allergic responses. Release large amounts of histamine in response to allergens leading to inflammatory responses
What are the two divisions of the adaptive immune system?
Humoral immunity B cells- involves production of antibodies
Cell mediated or cytotoxic community T cell
What cells produce antibodies and where do they mature?
B cells
In the spleen and lymph nodes
What are the three responses when an antibody binds to an antigen?
1) attract other leukocytes to phagocytize those antigens immediately (opsonization)
2) antibodies may cause pathogens to clump together or agglutinates forming larger insoluble complexes that can be phagocytized
3) Antibodies can block the ability of a pathogen to invade tissues (neutralize it)
Degranulation
exocytosis of granule contents
When an antigen binds to antibodies on the surface of a mast cell it causes degranulation or exocytosis of granule contents, releasing histamine and causing an inflammatory allergic reaction.
Five different isotopes of antibodies
IgG- IgD- IgM- IgE- IgA-
What happens once the correct antigen is exposed to a B cell
The B cell will proliferate and produce two types of daughter cells:
Plasma cells – that produce large amounts of antibodies
Memory B cells- which stay in the lymph node awaiting reexposure to the same antigen
Primary vs secondary response
Primary response is the initial activation it takes approximately 7 to 10 days.
Secondary response is more rapid and robust relies on lasting memory cells.
Positive versus negative selection of T cells
Positive selection allows only maturation of cells I can respond to the presentation of an antigen on MHC.
Negative selection refers to causing apoptosis in cells that are self reactive or activated by proteins produced by the organism itself (prevents autoimmune disorders)
The maturation of T cells is facilitated by what hormone?
Thymosin, a peptide hormone secreted by thymic cells
What are the three major types of T cells?
Helper T Cells (Th/CD4)
Suppressor T Cells (Th)
Killer (cytotoxic) T cells (CD8)
How do helper T cells coordinate immune response?
They secrete chemicals known as lymphokines.
These molecules are capable of recruiting other immune cells (such as plasma cells, cytotoxic T cells and macrophages)
CD4 or helper T cells respond to antigens presented on what type of molecules?
MHII
Most effective against bacterial fungal and parasitic infections since MHC – two presents exogenous antigens
What is the role of cytotoxic T cells in the adaptive immune system?
Kills virally infected cells by injecting toxic chemicals that promote apoptosis into the infected cell.
Respond to antigens presented on MHC I molecules. Most effective against viral and intracellular bacterial or fungal infections since MHC I presents and a genus antigens.
Suppressor or regulatory T cells
Express CD4+ but also express proteins called foxp3. Help tone down the immune response once infection has been adequately contained. These cells help prevent autoimmune diseases and help to turn off self reactive lymphocytes.
Memory T cells
Awaits repeated exposure to the same antigen when activated they carry out a more robust and rapid response.
Branch of memory T cells
What are the five types of infectious pathogens
Bacteria, viruses, fungi, parasites (including protozoa worms and insects), and prions (no immune defenses against prions)
Passive vs active immunity
Passive immunity-pregnancy/breast milk
Active- building up antibodies against specific pathogen (getting sick/vaccine)
Lymph nodes
Small bean shaped structures along lymphatic vessels that contain a lymphatic channel and an artery and vein.
They provide a space for the cells of the immune system to be exposed to possible pathogens.
Lymphatic fluid joins to form _________ in the _________ which then delivers the fluid to the _________ (near the heart)
Thoracic duct
Posterior chest
Subclavian vein
Function of the lymphatic system
Secondary system for circulation
3 Functions of the lymphatic system
Equalization of fluid distribution
(Net pressure drawing fluid in < net pressure pushing fluid out fluid remains in tissues lymphatic vessels help drain tissues and return fluid back to bloodstream)
Transportation of biomolecules
Transports fats from digestive system into blood steam through lacteals (lymphatic vessels in the small intestine)
Immunity
B cells proliferate immature in lymph nodes in collections call germinal centers
germinal center
Collections which are the site of B cell proliferation and maturation
Dendritic cells
Part of the innate immune system. Presents antigen fragments of proteins or other molecules from pathogens or cancer cells to the adaptive immune cells inducing them to attack bearers of the displayed antigens.
Natural Killer Cells
Destroys the body’s own cells that are become infected with pathogens. Also goes after cancer cells.
Look for down regulation of MHC, induce apoptosis.
