MCAT BIO CH. 9 PART 2 Flashcards
What are the three types of immunity?
Innate, humoral and cell-mediated
What is innate immunity?
General nonspecific protection the body provides against various invaders
What is the simplest example of innate immunity?
Skin
Lysozyme examples are in components of innate immunity such as:
Tears, saliva and blood
What is the complement system and what type of immunity is it considered?
A group of 20 blood proteins that can nonspecifically bind to the surface of foreign cells; its an innate immunity
What is humoral immunity?
Specific protection by proteins in the plasma called antibodies (Ab) or Immunoglobulins (Ig)
Each antibody molecule is composed of two copies of two different ______? What are they?
Polypeptides; light chains and heavy chains joined by disulfide bonds
What are the two regions that make up an antibody?
Constant region and variable (antigen binding) region
What are the five main types of immunoglobulins classes?
IgG, IgA, IgM, IgD, and IgE
What is the most antibody circulating in the plasma?
IgG Class
Where is IgM located?
Blood and B cell surface
Where is IgG located?
Blood
Where is IgD located?
B cell surface
Where is IgA located?
Secretions (saliva, mucus, tears, breast milk)
Where is IgE located?
Blood
What is the function IgM?
- Initial immune response
- Pentameric structure in blood
- Monomeric structure on B cell as antigen receptor
What is the function of IgG?
- Involving in ongoing immune response
- Can cross placental barrier
What is the function of IgD?
- Serves with IgM as antigen receptor on B cells
What is the function of IgA?
- Secreted in breast milk
- Helps protect newborns, dimeric structure
What is the function of IgE?
Involved in allergic reactions
What is an antigen?
Molecule an antibody binds to
How is the specificity of antigen binding determined by?
The fit of antigen in a small three-dimensional cleft formed by the variable region of the antibody molecule
What is an epitope?
A small sit on an antigen that an antibody recognizes within a larger molecule
What is a carrier based on antigens?
Small molecules that bound to an antigenic large molecule; the large molecule is considered a carrier
What is a happen?
When a small molecule bound to an antigenic large molecule creates a production of antibodies - its the small molecule
What are the three ways antibodies can contribute to removal of the antigen from the body?
- Inactivate antigen
- Induce phagocytosis of particle by macrophages and neutrophils
- Activate complement system forming holes in membrane and lyse cell
How are antibodies produced?
By a type of lymphocyte called B Cells
Where are immature B cells located?
Derived from precursor stem closings the bone marrow
What happens when an antigen binds to the antibody on the surface of the specific immature B cell?
Cell is stimulated to proliferate and differentiate into twi kinds of cells: plasma cells and memory cells
What do plasma cells do based on antigen and antibody?
Produce and secrete antibody protein into the plasma
What is different between plasma cells and memory cells?
Memory cells do not secrete antibody; they are pre-activated, dormant B-cells
What is clonal selection based on B-cells?
Selecting B cells with specific antigens binding
In general, every cell of the body is said to possess the same copy of the genome. Is it true in the immune system?
No; recombination during development of B cells and T cells makes these exceptions
What is the primary immune response?
First time a person encounters an antigen; takes too long for B cells to proliferate and prevent symptoms of the infection from occurring
What is the secondary immune response?
Second time a person is exposed to the antigen
What are the two types of T-cells?
T helpers and T killers
What are T helpers also called?
CD4 cells
What are T killers also called?
Cytotoxic T cells - CD8 cells
What is the role of the T helper?
Activate B cells, T killer cells and other immune cells
How does the T helper communicate with other cells?
As the central controller of the whole immune response, they release special hormones called lymphokines and interleukins
What part of the body is considered the central controller of the whole immune response?
T helper
What host cells do T killer cell destroy?
- Virus-infected host cells
- Cancer cells
- Foreign cells
The T in T cell stands for:
Thymus
Where are the T cells produced?
In the bone marrow during childhood
What is the T-cell receptor?
The protein on the T-cel surface that can end antigen
What is a major group that the T-cell can recognize on the surface of the cell?
Major histocompatibility complex (MHC)
What are the two types of major histocompatibility complex MHCs?
MHC I and MHC II
What is the role of MHC I and where are they found?
Found on the surface of every nucleated cell in the body; role is to randomly pick up peptides from the inside of the cell and display on the surface
Why does the MHC display random peptides on the surface?
T cells can then monitor cellular contents
What cells can have MHC II?
Antigen-presenting cells (APCs)
What are the antigen-presenting cells?
Macrophages and B cells
What is the role of the antigen-presenting cell?
Phagocytize particles or cells, chops hem up and display gradients using the MHC II display system
How is the T cell fully activated based on MHC?
When the T cell binds to both antigen and the MHC molecule itself
What is the site of synthesis of all the cells fo the blood?
Bone marrow
What is the purpose of the spleen?
Filters the blood and is a site of immune cell interactions
What is the purpose of the thymus?
The site of T cell maturation
What is the purpose of tonsils?
Masses of lymphatic tissue that help catch pathogens which enter the body through respirations or ingestion
What is the purpose of the appendix?
Found in the beginning of the large intestine but is not required for survival
What is tolerance of the immune system?
Will only recognize and destroy foreign antigen and ignore all norma proteins and cell structures
Why do B cells go through a selection process? Where?
To eliminate self-reactive cells; in the bone marrow
What happens to an immature B cell whose surface receptors bind to normal soluble proteins?
Become unresponsive or anergic
Where do T cells go through the selection process?
Thymus
