Lymphatic and immune system Flashcards
(31 cards)
explain the direction of lymph (vessels)?
starts as lymphatic capillaries then goes to larger lymph vessels which then merge to lymph ducts. All of the ducts merge into the thoracic duct which drains into a neck vein
what are lacteals?
special lymph vessels which carry lipids from the intestine in the form of chylomicrons.
explain how the blood pressure and the lymphatic system work?
when blood goes through capillaries, pressure decreases dramatically. nutrients, neutrophils, macrophages, and wastes pass through the intercellular clefts of the endothelial cells.
when this occurs a lot of water is also lost. Lost water and protein are taken up by the lymph system and brought back into circulation.
oncotic pressure tries to retain water (albumin) while hydrostatic pressure and tissue osmolarity encourage it to leave the blood.
what are the 5 components of innate immunity?
- skin = protective barrier
- lysozyme’s in tears and saliva. (they attack bacterial peptidoglycan walls)
- monocyte macrophage’s and granulocyte neutrophils which non-specifically perform phagocytosis
- stomach acidity
- complement system of proteins (these proteins non-specifically bind the surface of foreign material)
what is humoral immunity
antigen-antibody system which is specific for specific pathogens
explain the general structure of an antibody.
composed of a 2 light chains and 2 heavy chains connected by disulphide bonds. additionally each light chain- heavy chain pair has a variable region and a constant region (variable on the light chain side)
what is an epitope
the binding site on the antigen that an antibody binds too
what is another name for antibody?
immunoglobulin
what are the 5 classes of antibodies based on their constant regions?
Ig prefixes all of them…
M A D E G
what is the most common plasma antibody
IgG
explain antibody Ig M
location and function
location: blood + B cell surface
function: initial immune response
explain antibody Ig A
location and function
location: secretions i.e. saliva
function: helps protect newborns and GI
explain antibody Ig D
location and function
location: B cells
function: acts as antigen receptor like IgM
explain antibody Ig E
location and function
location: blood
function: allergic reactions
explain antibody Ig G
location and function
location: blood
function: ongoing immune response. This can cross the placental barrier
explain the production of mature B cells (5 steps)
- immature B cells are derived from bone marrow stem cells
- the genes that encode the antibody proteins to be produced are recombined giving rise to many variable regions.
- Once recombination occurs, the immature B cell expresses antibody molecules on it’s surface
- the antibody presenting B cell then comes into contact with an antigen which stimulates it to proliferate
- A. The immature B cell becomes a plasma cell which actively secretes the antibody
- B. The “” becomes a memory cell ( dormant B cell waiting for recurrent infection)
what is primary and secondary immune responses?
primary immune response –> upon first infection, immature B cells bind the antigen and proliferate which takes time therefore we experience symptoms.
Secondary immune response –> due to the presence of memory B cells, up second infection we amount an immune so fast symptoms don’t show (person is said to be immune)
this is how vaccines work.
what are lymphokines and interleukins?
these are hormones released by T helper cells (CD4 cells) which help in communication with all other cells
what are the two types of T cells? what do they do?
T helper (aka CD4 cell): activate B cells, help other T cells
T killer cells (cytotoxic cells or CD8 cells): they kill
explain how a helper T cell can be specific to an antigen but not produce antibodies for it?
helper T cells recognize an antigen and then activate a killer T cell or B cell to deal with it.
where do T cells mature?
thymus
what is the MHC 1 complex? whats its involvement in cell-mediated immunity?
MHC 1 complex is a protein that is expressed on all nucleated cells (RBC’s aren’t nucleated). The job of these proteins is to randomly take peptide pieces in the cell and present them on the cell surface for T cells to check over. If the cell is infected, it may randomly present foreign material and therefore be recognized by T killer cells as an infected cell.
explain MHC 2 complex?
The MCH 2 complex is only presented on cells called Antigen Presenting Cells (APC’s). These include B cells and macrophages. these phagocytosis particles or cells and display fragments of them on their surface via the MHC 2 proteins. T-helper cells recognize this and activate B cells and T killer cells
true or false, Helper T cells can become activated when they encounter a foreign pathogenic particle in the blood.
false!! HELPER T CELLS CAN ONLY RECOGNIZE ANTIGEN PRESENTING CELLS.
