essential immunology 2

Question 1

what are the functions of the lymphatic system?

Answer 1

1- drainage of tissues
2-immunity
3-transport and absorption of fats

Question 2

what is the lymphatic system made up of?

how is the system comprised?

Answer 2

lymph which is carried in lymphatic vessels ( capillaries-venues-trunks-ducts)
lymph- afferent vessels-lymph node ( filter)- efferent vessels- duct (thoracic and right lymphatic) -blood

Question 3

proprieties of the lymphatic system?

Answer 3

1- start at capillaries
2- made up of squamous epithelial cells which form valves- prevent anything from flowing out
3- found everywhere except in bone marrow and CNS where there is no blood vessels

Question 4

which are the primary lymphoid organs?

what is there function

Answer 4

• thymus- T cells differentiate
• bone marrow
  function: where blood cells initially produced= hematopoiesis

Question 5

which are the secondary lymphoid organs?

what are their functions?

Answer 5

1- spleen
2- tonsils
3- peyers  patches 
4-lymph nodes 
functions: 
-purifies lymph before it reaches the blood
-produces B-cells and maintains T-cells
-removes antigens 
-responds when antigens are present

Question 6

how is the spleen set up

Answer 6

white pulp: 
-made up of lymphocytes
- involved in APCs and T/B cells.
T cell lymphocytes around central artery-tissue fluid=Periarterial lymphoid sheath (PALS)
B cell lymphocytes  at margines.

Red pulp:

• made up of lymphocytes and macrophages and dendrites
• involved in blood filtration e.g. removing damaged RBCs

Question 7

T-cells different types?

Answer 7

1-T memory: arise from differentiated/partially differentiated cell. can further differentiate in response to re-exposure to antigen.
2-T-helper/CD4:
does not kill, activates T cells and important in activating B cells
3- T-killer cell/CD8:
release perforin which forms a whole in membrane in infected cell.
releases granzyme B- causes apoptosis.

Question 8

selection of T cells

Answer 8

T cells develop in the bone marrow and then the thymocytes move to the thalamus where they differentiate
1- positive selection.
CD4,CD8 and TCR receptors added.
tested for response for MHC receptor.
if they don’t respond, they are killed by apoptosis
2- negative selection
tested to see if they respond to self MHC.
if they bind then, then they are destroyed by dendritic cells and macrophages.

sometimes cells with a low affinity for can pass through the system and into the blood. this is when autoimmune disease develop.

Question 9

different classes of MHC

Answer 9

class 1- found in all cells
class 2
- only found in antigen presenting cells.
-present antigen to T cells and activates B cells.

Question 10

T-helper 1 and T-helper 2

Answer 10

Th1- T-memory cells

Th2-produce B cells which then differentiate into plasma cells and memory B cells.