Term
Cell components of lymphatic tissue
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Definition
Lymphocytes (B/plasma and T)
Antigen presenting cells (dendritic, monocyte, macrophage)
NOT neutrophils (normally)
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Term
| types of lymphatic tissues |
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Definition
Diffuse unencapsulated
Dense unencapsulated
Dense encapsulated |
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Term
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Definition
gastrointestinal, urogenital and respiratory tracts
(Tissues exposed to the ‘outside’)
Subepithelial leukocytes
- Lymphocytes (primarily T cells), plasma cells, macrophages |
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Term
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Definition
Found in the gastrointestinal, urogenital and respiratory tracts
(Tissues exposed to the ‘outside’)
Examples:
Tonsils (pharynx)
Peyer’s patches (gastrointestinal tract GALT)
Bronchiole associated lymphoid tissue (BALT)
Subepithelial aggregates of leukocytes
- Lymphocytes (primarily T cells), plasma cells, macrophages
May form primary and secondary lymphoid follicles |
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Term
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Definition
Lymph nodes
Spleen
Thymus
Bursa (birds)
Hemal nodes (young ruminants)
Hemolymph nodes (mythical?) |
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Term
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Definition
Subepithelial aggregates of lymphoid cells
– Lymphoid follicles
Crypt: human, horse, ruminants, swine
no crypts - carnivores, ruminants
(ruminants have both depending on location) |
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Term
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Definition
Primary follicles, secondary follicles
epithelium over lymphoid tissue has M cells and intraepithelial lymphocytes
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Term
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Definition
not immunologically active, no germinal centers, resting B cells and dendritic cells
Become secondary after antigenic stimulation |
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Definition
immunologically active, have germinal center and mantle zone
germinal center: B cells proliferate, dendritic cells, macrophage
mantle zone: small resting B cells, surrounds g center |
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Term
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Definition
ABSENT in AVIAN spp
Capsule – dense white fibrous connective tissue
sub-dividing trabeculae
cortex/medulla/hilus
pigs are "inside out" |
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Term
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Definition
outer (subcapsular) portion is blue
- contains lymphocytes, often follicles, B cells
deep portion is white paracortex
- contains T cells (no follicles)
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Term
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Definition
inner portion
pink
Cords of leukocytes
• B cells
• Plasma cells
• Macrophages
Separated by sinuses |
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Term
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Definition
Vein
Artery
Efferent / Outgoing lymph vessel |
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Term
| Lymph circulation in lymph nodes |
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Definition
from capsule to hilus
Afferent vessels (draining into LN) penetrate the capsule
empty into subcapsular sinus (separate capsule from cortex)
SC sinus drains into cortical sinuses
cortical into medullary
medullary empty into efferent vessels
sinuses are fenestrated allowing foreign material and organisms to be transferred (can help spread infection/cancer)
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Term
| Blood circulation in lymph nodes |
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Definition
artery enters at hilus
vessels follow trabeculae
Capillaries in paracortex
High endothelial venules (HEVs) - thickened epithelium gets lymphocytes out of blodo
vein exits at hilus
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Term
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Definition
- Blood cell formation and production
– Blood storage
– Blood filtration
– Red blood cell destruction (turnover)
– Phagocytosis
– Hemoglobin and iron metabolism
– Immune response |
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Term
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Definition
caspule lined with mesothelium, made of fibrous CT, has sm muscle for contraction, elastic fibers help it expand
No cortex and medulla
red pulp and white pulp |
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Term
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Definition
White pulp:
– Periarteriolar lymphoid sheaths: T cells surrounding central arteries
– contains Lymphoid follicles
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Term
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Definition
– Capillaries empty blood into sinuses
Sinuses lined by phagocytic cells
• Remove debris, abnormal cells etc
• Macrophages phagocytose ‘spent’ erythrocytes →
hemoglobin → hemosiderin
– Golden brown intracellular pigment |
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Term
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Definition
No afferent lymphatic vessels
Efferent lymphatics arise in the white pulp
– Exit through the hilus |
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Term
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Definition
Splenic arteries enter at hilus
– Divide into trabecular arteries
– Capillaries empty blood into sinuses (red pulp)
– Veins exit at hilus
– Very similar to blood circulation in lymph nodes |
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Term
| Spleens in different species (types of spleen) |
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Definition
Defensive spleens
– Primarily lymphoid tissue
– Few trabeculae and smooth muscle
– Lagomorphs (rabbits), humans
Storage spleens
– Less lymphoid tissue
– Prominent trabeculae & smooth muscle
• Can store 1/3 of blood volume
– Horses! |
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Term
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Definition
Young ruminants
– Less prominent with age
• Along the ventral spinal column
• Small (<5mm) and red
– Mini spleens
• Blood filled sinuses
• No lymph vessels |
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Term
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Definition
Perirenal in sheep and goats
• Lumbar in cows
• Mythical?
• Cross between lymph nodes and hemal nodes
– Blood and lymph intermix in the sinuses |
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Term
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Definition
Derived from the endoderm of the 3rd and 4th
pharyngeal pouches
• Starts out purely epithelial
– Lymphocytes progenitors from the bone marrow
migrate in → lymphoepithelial organ
• Primary lymphoid organ |
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Definition
Function
– Production of lymphocytes (T cells)
– Development of self tolerance (Atrophies with age) |
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Definition
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Term
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Definition
– Extends septa into the parenchyma, sub-dividing it
into lobules
• Septa end at the corticomedullary junction
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Definition
Cortex (darker blue)
– Densely packed small lymphocytes (T cells)
• Mitotic figures |
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Definition
paler blue
– Fewer lymphocytes
• More prominent stroma
– Thymic interdigitating cells (antigen presenting
cells)
– Hassall’s (thymic) corpuscles
• Epithelial cells
– Concentric whorls
– Mineralization
– Keratinization |
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Term
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Definition
NO afferent lymphatic vessels
• Efferent lymphatic vessels
– Exiting lymphocytes population secondary
lymphatic organs
• Spleen, lymph nodes, tonsils etc |
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Term
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Definition
only in birds
blind sac from dorsal wall of proctodeum |
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Term
| Bursa function and structure |
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Definition
Function: Development of B cells
Structure
– Lined by simple (to pseudostratified) columnar
• Tightly packed, polyhedral lymphoid follicles
– Separated by connective tissue
– These lymphoid follicles have a cortex and medulla
» Not called germinal center and mantle zone
• ‘M cells’ |
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