Immune system Flashcards
how do cells communicate?
Direct interaction, diffusible chemical communication, electrical signals
Threats handled by our immune system
Pathogens, abnormal cells such as tumour, our own dead or damaged cells, certain nonpathogenic foreign substances, out own healthy cells (Inappropriately)
Types of defence
Innate and adaptive they both communicate with one another
Innate defenses
Barriers- skin mucus membrane
phagocytes, macrophages, Natural killer cells (attack cancer)
inflammatory-response to tissue damage
Fever
Adaptive defence
Specificity
diversity
Self/nonself recognition
memory
Antibodies and T-cell receptors
an antibody is a individual molecule a set of antibodies (Ab) is called an immunoglobulin (lg) class
two regions constant region (C)- same in each lg class
Variable region (V) - Different in each antibody
What is an Epitope?
Part of the antigenic molecule that binds the antibody
How are different antibodies generated?
By editing fenes during development of B cells that produce antibodies. The lg genes are randomly and independently mutated in each develpoing B cell
What are T-cell receptors?
Glycoproteins located on the surface of T cells
- manifest specificity and diversity
- bind to antigens
- their diversity is also generated by gene rearrangments
What are Lymphocytes and what do they do?
They are adaptive defense cells derived from stem cells in the bone marrow
What are B lymphocytes
B-cells mature in bone marrow
What are T lymphocytes
T-cells mature in the thymus
What is the B cells Structure?
Have antibodies on surface that serve as antigen receptors. Binding tells the cell that there is a foreign molecule
B cell activation
Activated by antiden binding of by inter activation with a helper T cell
What do antibodies do?
Serve as membrane bound receptors in B cells
-coast virus and bacteria, preventing their attachment to epithelia
Coat cells, viruses and particals for macrophage recognition and destruction
What do T-cells do?
Helper T cells provide links between macrophages, humoural immunity and cell mediated immunity
T cells will activate B cells and cytotoxic T cells
What are cytotoxic T cells?
activated by T helper cells and infected cells
they will poke holes in the plasma membrane of the target cell
What is immunological memory
Secondary response to an antigen is faster and greater than the primary one.
this is due to memory cells that are produced by the first exposure
Somatic hypermutation occurs during the proliferation of the memory cells
How do you aquire immunity
vaccination
passive immunity-antibodies are supplied directly from the outside
What are polyclonal and monoclonal antibodies
Polyclonal antibodies have different epitopic specification and bind to different epitopes of the same antigen
Monoclonal antibodies all have the same epitopic specificity and bind to one epitope only
Type A blood
Has A antigen; produces anti-B antibodies and will react to type B blood
Type B blood
Has B antigen; produces andti-A antibodies and will react to type A blood
Type AB blood
Has both antigen; produces no anti-A or anti-B antibodies; can receive any transfused blood
Type O blood
Has no antigen; produces anti A and anti B antibodies; can receive only type O blood, but can be transfused to any type blood
