What is the clinical pathology aspect of the hemic-lymphatic system?
Blood
- marrow
- circulating pools
What is the immunologic aspect of the hemic-lymphatic system?
Lymphatic system
- lymph nodes
- spleen
- thymus
- MALT
Blood
- erythrocytes
- leukocytes
- platelets
- -> blood is 8% BW
- -> 35-45% cells = Hct = PCV (55-65% fluid)
What is the difference between plasma and serum?
Plasma: fluid that has not been allowed to clot
Serum: fluid that has been allowed to clot
You should expect to see more _____in plasma
Protein
White Blood Cells
- leukocytes
- discrete cells (no tight attachments)
- mesodermal origin (bone marrow)
Granulocytes vs. agranulocytes
Granulocytes
- basophils, neutrophils, eosinophils
Agranulocytes
- monocytes, lymphocytes
Neutrophils
Polymorphonuclear leukocytes
- discrete (10-12 microns)
- lobed nucleus, “non-stain” granules
- chemotaxis, amoeboid motility
- variable amount of cytoplasm
- first responders - make pus
Neutrophils are associated with ______
Bacterial infections
Eosinophils
- discrete (10-12 microns)
- bi-lobed nucleus, “red” granules
- chemotaxis, amoeboid motility
- variable amount of cytoplasm
- associated with parasites and allergic reactions
Basophils
- extremely rare (found in less than 1% of leukocytes)
- discrete (10-12 microns)
- lobed nucleus/basophilic granules
- function = unclear
Lymphocytes
- discrete (10-12 microns)
- large central nucleus (spherical and rigid)
- minimal to moderate cytoplasm
- thymus or bursal
Monocytes/macrophages
- discrete (15-25 microns)
- large bean shaped nucleus
- moderate to abundant cytoplasm
- professional phagocytes
- associated with granulomas!!
Platelets
Thrombocytes
- discrete 3-5 microns
- cellular fragments
- anuclear
- derived from megakaryocytes
- bags of clotting factors
Lymphatic system
Immune system
- widely distributed: surface (mucosa) oriented, internal surveillance
- closely aligned with cardo/blood
- many cell types
Lymphatic vessles
Resemble veins –> carry lymph
- drain excess tissue fluid
- afferent lead to lymph nodes
- efferent leave lymph nodes
- thoracic duct empties lymph back into circulation
Lymph node function
- small, encapsulated organs
- along lymphatic vessels
- filter (surveillance) lymph
- phagocytosis/ immune response
Lymph node structure
Afferent/efferent - capsule - hilus Cortex Medulla - cords - sinuses (site of filtration) Trabeculae - DCT from capsule - adjacent sinus
Afferent lymph vessels enter the node thru the _____
Capsule
Cortex
Nodules (germinal centers)
node does NOT equal nodule
Cells of the cortex
- reticular cells (collagen and reticular fibers)
- dendritic cells: Ag presenters and T areas
- macrophages: phagocytes, Ag-present
- follicular dendritic cells: B areas (folls)
Reticular fibers allow organ to _____
Stretch/relax depending on workload
High endothelial venules
Fluid resorption
Circulating lymphs
Thymus
- lymphoepithelial organ
- anterior mediastinum/thoracic inlet
- natural regression
- T lymphocyte development
- “sweet breads”
