2.4 Immune Organs I

What occurs i nthe red bone marrow?

hematopoiesis

What happens in the bone marrow?

1. production and maturation of blood cells

2. b cells rearrenge and are tested for self reactivity

3. long lived plasma cells chill here

how to things enter or leave the bone marrow?

through perisoteal caplilaries that form into sinusoids which further drain into veins

What are reticular cells?

they are cells that suround the sinusoids

1. control acess to sinusoids

2. secrete regulatory factors

3. produce reticular fibers

T or F mature cells are often smaller than their precursors?

true

Where to T cells enter the thymus?

at venules at the cortico-medullary junction, then through the cortex, finish at the medulla

What cells support T cell maturation in the thymus?

macrophages, dendritic cells, and epithelial cells

What are hassall’s corpuscles?

swirls of epithelial cells that contribute to T cell development

AKA thymic corpuscles

What is the special name for thymic epithelial cells?

stellate

What is the purpose of thymic epithelial cells?

to test T cells for self reactivity by presenting self antigens

Where are cells less dense? medulla or cortex?

medulla (easier to see stuff)

What are some granulocytes?

neutrophils, esosinophils, and mast cells

What is usually the first responder cell at a site of infection?

neutrophils (if seen at high number think infection)

If neutrophils have a weird watery appearance this can mean what?

indicates bacterial infection

What are band neutrophils? what does it mean when increase numbers of these are seen in the blood?

immature ones

indicates a left shift meaning the bone marrow is putting in the hours

What is the purpose of eosinophils?

defense against parasites (release of toxic and pro inflamatory stuff)

if overactive, can cause allergies

Where are eosinophils found?

usually in tissues but can be found in blood

T or F cats are prone to eosinophil disorders?

t

What is the importance of mast cells?

defend against parasites w

where are mast cells commonly found?

in tissues usually nean surfaces exposed to pathogens

Can B and T cells be distinguished via cytology?

no

What are monocytes?

precursors of macrophages