organs of the immune system Flashcards
what are lymphoid organs?
parts of the immune system that play a crucial role in the body’s defense against infections and diseases.
what are the lymphoid organs responsible for?
production and maturation of lymphocytes,
what are the key lymphoid organs?
bone marrow
thymus
spleen
lymph nodes
Tonsils and Adenoids
Peyer’s Patches
summarise the primary lymphoid organs- bone marrow
bone marrow site of generation of all circulating blood cells in an adult including immature lymphocytes and is site of b cell maturation
site of differentiation and maturation of WBC
site of immune response of b cells specifically in secondary immune response
summarise lymphoid organs - thymus
both t cells and b cells are ‘born’ in the bone marrow
- b cells can mature in the bone marrow whereas t cells have to mature in the thymus (where they move to)
what happens to immature lymphocytes?
become committed within the primary lymphoid organs
Only after maturation has occurred that cell is IMMUNOCOMPETENT
what are the secondary lymphoid organs?
adenoids
peyers patches
appendix
what is the function of the lymph nodes?
contain high concentrations of leukocytes that filter out microbes and toxins
what is the function of spleen>
of the blood circulatory system has the same function as the lymph nodes
how can the lymph nodes and the spleen may be affected?
infected by the organisms that have collected
during filtration
summarise the lymphatic system? 1/3
As blood circulates under pressure, plasma seeps through thin walls of capillaries.
summarise the lymphatic system? 2/3
Much of this fluid returned to blood but some enters lymphatic system, which is referred to as “lymph”.
what is the structure of a lymph node?
outer cortex- filled with lymph follicles
outer edge of follicle contains more t cells
inner germinal center is the site of b cells prolifeeration
summarise the lymphatic system? 3/3
When a foreign antigen gains entry to the tissues, it is picked up by lymphatic system and taken to lymph nodes that trap the antigen
what is the inner medulla of the lymph node responsible for?
medullary cords of the lymphcytes, macrophages, plasma cells (activated b cells)
what can the fibres of the lymph node act as?
net to catch any debris or cells that are present in the lymph
reticular fibres?
Macrophages and lymphocytes attack and kill any microbes caught in the reticular fibers.
what is extravasation?
immune cells travel back and forth from the blood and lymph CS and interact with extra vascular tissues in the process
what is extravasation? simple
escape of fluid, cells, or other substances from blood vessels into surrounding tissues
what can cause extravasation?
including inflammation, injury, or certain medical procedures
what is lymph?
a fluid containing
-water
-sugars
-wbc
-protein
what are lymph vessels
carry lymph within the lymphatic system
lymph capillaries are the smallest of the lymph vessels
how do leukocytes travel from one system to another
Lymph carrying antibodies
and immune cells collect in
thoracic duct where the
lymph empties back into the
blood circulatory system
what happens when the lymphatic system goes wrong?
lymphatic filariasis- symptoms` include swelling and enlargement of the arms and legs
People with elephantiasis have what?
impaired immune function due to damage to the lymph system
summarise the spleen?
largest lymphoid tissue
what are the functions of the spleen
Filters out older RBCs
Responds to Antigens in circulatory system
Produces activated B cells
Stores platelets
In fetus: site of haematopoiesis
what happens when the spleen gets damaged?
; splenectomy increases risk of bacterial infection
describe the tonsils?
masses of lymph tissue designed to filter tissue fluid, not lymph
what is tissue fluid?
Tissue fluid, also known as interstitial fluid or extracellular fluid, is a clear, colorless fluid that surrounds the cells within tissues.
