Immunology Flashcards
What are the features of a mast cell?
Found across many tissues, mainly near small blood vessels
Upon activation, release substances that effect vascular permeability
Granules contain histamine and heparin
Best known for their role in allergy
Also thought to play a part in protecting mucosal surfaces from pathogens
What are the features of a neutrophil?
Most predominate type of granulocyte in blood
Phagocytic cell
Most numerous component of the innate immune system
Also found at sites of acute inflammation
Where are all immune cells created and matured?
Primary lymphoid tissues
What are immune cells produced from?
Haemopoietic stem cells
What can lymphocytes and some mononuclear phagocytes do?
Can re-circulate between non-lymphoid tissues and secondary lymphoid tissues
What does the recirculation of lymphocytes and some mononuclear phagocytes do?
Increases the liklihood of them being exposed to the correct pathogen
What are the primary lymphoid tissues?
Thymus and bone marrow
What are the secondary lymphoid tissues?
Waldeyers ring (tonsils and adenoids) Bronchus associated lymphoid tissue Lymph nodes Bone marrow Spleen Lymphoid nodules Mesenteric lymph nodes Peters patch Urogenital lymphoid tissue Lymph nodes
What are primary lymphoid tissues also known as?
Central lymphoid organs
What are primary lymphoid tissues
Tissues where lymphocytes develop to a stage where they are able to recognise antigen
What is bone marrow also the site of origin of?
Red blood cells and platelets
What are the two types of bone marrow?
Red and yellow
What is the 2nd stage of lymphoid development after the hematopoietic stem cell?
Common lymphoid progenitor
What does the common lymphoid progenitor cell divide in to?
Pre B cells
Pre T cells
Lymphoid dendritic cells
What do pre B cells divide in to and where do they go?
B1 and B2 cells - in to systemic circulation
What do Pre T Cells divide in to?
Natural killer cells and pro t cells- the thymus
Where do B cells mature?
Entirely in the bone marrow
What is the anatomical position of the thymus?
Located in the lower part of the neck, deep to the sternum, slightly inferior to the larynx
What happens to the thymus during childhood?
Gradually enlarges as it is most active
What happens to the thymus after puberty?
Begins to reduce in size and function
Why are most T cells destroyed in the thymus or bone marrow?
They fail to produce a useful T cell receptor
What happens in the cortex?
Positive selection - selects for only those T cells that are capable of recognising self MHC and peptide
What happens in the medulla?
Negative selection - eliminates those T cells which would recognise self peptide and therefore would be dangerous to the body
What are secondary lymphoid tissues also known as?
Peripheral lymphoid organs
What do lymph vessels do?
Drain tissue fluid from connective tissue collectively known as lymph
What do the lymph vessels drain via?
The thoracic duct in the the subclavian vein
What are lymph nodes?
Highly organised bean shaped structures at junctions between lymph vessels
Where are lymph nodes aggregated?
At specific sites such as neck and groins
What do the lymph nodes act to do?
Filter lymph from tissues
