Topic 7- Immune System Flashcards
What are granulocytes
White blood cells with granules
Neutrophils , basophils, macrophages, eosinophils
What is the most dominant granulocyte and involved in inflammation
Neutrophils
How do you distinguish them from others
Multi loved (3 loved nuclei)
What are eosinophils for
Atopic asthma and parasitic infections
What do they look like
Usually 2 lobes and then granules/dots outside of them
Which granulocyres are lowest in numbers in blood
Basophils
What sort of dye stains basophils and what does this mean
Basic dyes meaning they have acidic granules
What sort of things do they contain
Histamine, lt, vasoactive mediators, paf
How do you find macrophages and distinguish against lymphocytes
Uni lobed nucleus and bigger than lymphocytes which look the same as macrophages
Which cells are more dotty when stained basophils or mast cells
Mast cells. Have heavier granules
Name the 3 types of lymphocytes
B , t and NK cells
What do NK cells do
Granular cells which detect and attack virally infected cells even without ag receptors
Where are mast cells seen
Small blood vessels , connective tissue, mucosa
Where do they originate
Heamatopoirtic sc in primary lymphoid organs the bm and thymus
Which cells can move to secondary lymphoid organs once made to increase ag encounters
Lymphocytes and mononuclear phagocytes
Give all secondary lymphoid tissues
Adenoids, tonsils, peyers patch, appendix, lymph nodes, spleen, subclavian veins, bone marrow, large intestine, thoracic duct in thorax, thymus near heart
What other types of cells are made in bone marrow other than immune cells
Rbc and platelets
What are primary lymph also called
Central lymphoid organs
What are the 2 types of marrow
Red for haemotopoiesis
Yellow for adipocytes
Where does haematopoiesis occur in children vs adults
Occurs in all medullary cavities in children but only the axial skeleton in adults, all other cavities are adipocytes filled
Where do lymphocytes develop from
Common lymphoid progenitor
Explain the diversion from clp
To pre b and pre T cells
Pre b then make pro B cells
T cells make NK cells or pro t cells
Which cells are made entirely in bm vs thymus
B cells in bm, pre T cells move to the thymus for development
Where is the thymus located
Deep to the sternum in the neck, inferior to the larynx
When does it start to stop enlarging
Puberty
Where do pro T cells enter for positive selection to see if they recognise MHC 1 or 2 and which cells
Cortex
Via cortical epi cells presenting MHC 1 or 2
What happens to the 95% that don’t recognise it
Apoptosis after 4 days
What happens to those receiving survival signal
Move to medullary region where negative selection occurs and those who recognise self peptide too well die after 4 days
Is lymphocyte migration to secondary lymphoid / peripheral lymphoid organs random
No. They bind and home specifically
How do they enter the slt
Via HEVs which express adhesion molecules which lymphocytes bind to and enter in
What is diapedesis
Lymphocyte migration to lymph node
What are lymph vessels
Vessels which drain lymph (fluid) from connective tissue/infective sites
Where do they empty
Via the thoracic duct draining it to the right subclavian vein (joins to the vena cava)
What does lymph unidirectional flow depend on
Valves
What does this process allow
Ag to get to the lymph nodes from connective tissue to the lymph vessels to TD to subclavian vein to lymph nodes
Where do lymph nodes aggregate
Neck and groins mainly
Where do afferent lymph vessels enter
The cortex (outside of lymph node)
Then pass through paracortex
Then out via efferent vessel at medullary area
What are the areas without a blob/germinal centre on the cortex area(outside) called
Primary lymphoid follicles where mostly b cells
Where are the T cells mostly
Paracrotical area (below the follicles)
What is the middle but which looks like a star called
Medullary sinus
What surrounds the medullary sinus
Medullary cords with macrophages and plasma cells
Where do hevs wtih lymphocytes enter lymph nodes
Paracortex
Where are resting vs active B cells
Resting in primary vs active are in the germinal cnetre forming secondary follicles
What happens if no ag are met in lymph nodes
Leave via the efferent and get to blood through the thoracic duct
Where is the spleen in respect to ribs
Posterior behind ribs at T9-11
How are ribs separated from spleen
Diaphragm
Which area of the abdomen is it in and what does it rest on
Left lumbar next to tail of pancreas and rests on the left colic flexure
Where is ag from blood filtered in the spleen to t, b and dc cells
White pulp
What does the red pulp do
Filtration of the well perfused spleen and removing damaged or old RBCs
Which artery and vein run through spleen
Trabecular artery and vein
What is the outside of spleen called
Capsule
What is the outer bit of white pulp calle
Marginal zone
What is inside of the marginal zone
Marginal sinus
The big circle in middle is called what and what is it surrounded by
The germinal centre surrounded by the b cell corona
What is the other part which isn’t the bbcell corona called inside of the marginal sinus
PALS (T cell zone)
Peri arteriolar lymphoid sheath
What runs through pals
Central arteriole as red pulp is highly perfused
What makes up the galt
Adenoids/tonsils, peyers patch , appendix
What are the tonsils divided by and where are the adenoids
Uvula dangly rhing in the back of mouth
Adenoids are behind nose and soft palate
What are the wrinkles on tonsils called
Crypts
Where are peyers patches in si mainly
The ileum under the epithelial cells
What sorts of follicles are present
Primary and secondary but T cell follicles usually lower down
What presents ag to them mainly
M cells
What is the appendix associated with
The caecum right of the large intestine
Does it have a definite role in immune system or is it just an area prone to infection
Not proved yet but v susceptible
What artery supplies it
Appendicular arteryb
What dyes stain eosinophils
Acidic dyes like eosin as they have basic protiens
What is outside of lymph node called
Marginal sinus
Where do lymphocytes and some phagocytes enter lymph node
Hev where they detect ag. If ag no detected it will leave again via efferent lymph vessel entering blood via thoracic duct
What blood supplies run close to the pulp
Trabecular
What separates white pulp from red pulp in spleen
The marginal zone
What surrounds the germinal centres in spleen
B cell corona
Are B cells in cortex or medulla of lymph node
Cortex
Where do T cells enter ln
Hev at paracortical area
