Blood Histology 9/26 Flashcards
What is the ratio of the 5 white blood cells?
Neutrophils > lymphocytes > monocytes > eosinophils > basophils
Never Let Monkeys Eat Bananas
Describe platelets (thrombocytes)
Anucleated cell fragments from megakaryocytes in bone marrow. Function in blood clotting. Live 7-10 days.
What is the function of the 3 lymphocytes?
Immunity - recognize and respond to antigens
B cells: produce circulating antibodies
T cells: mature in thymus, mediate immunity
NK cells: kill virus infected and tumor cells. Large.
What is the largest wbc?
Monocytes
What are the functions of monocytes?
Migrate to tissues and differentiate into macrophages.
Act as antigen presenting cells for lymphocytes
Phagocytosis
What mononuclear phagocytizing cells are derived from monocytes and where are they located?
Osteoclasts- bone Microglia- CNS Macrophage (histiocyte)- tissues Langerhans cells- epidermis Dendritic cells- lymph nodes, spleen Alveolar macrophage- lungs Kupfer cells- liver
Where do granulocytes work?
Connective tissue & organs. Live a few days.
What are neutrophils?
PMNs: 3-5 lobed nucleus, Barr bodies in females,
function:
•phagocytize bacteria and foreign organisms
•first responders in inflammation.
•induce fever via IL-1
What do Azurophilic (1*) granules contain?
Lysosomes:
myeloperoxidase defensins
hydrolytic enzymes
What do specific
(2*) neutrophil granules (most abundant) contain?
- Type IV collagenase
- Lactoferrin- binds iron to deprive and kill bacteria
- Lysozyme- degrades cell wall of gram positive bacteria to kill them
What do 3* neutrophil granules contain?
MMPs: collagenase, gelatinase
What are the functions of eosinophils?
Allergic & inflammatory
Kills helminthic parasitic worms
Modulates inflammatory effects of basophils and mast cells- inactivate leukotrienes and histamine.
Phagocytosis of antigen-antibody complexes
Where are eosinophils found?
CHRONIC inflammation, commonly in CT of respiratory, digestive, vaginal tracts
What are the specific granules of eosinophils?
- neutrotoxins: attack parasites
- histaminase: mediates allergic rxns
- arylsulfatase: neutralizes leukotrienes
- eosinophil peroxidase: antibacterial
What is located in the specific granules of eosinophils?
Cr- characteristic crystalloid bodies: contain arginine-rich major basic protein; disrupts membranes of parasites.
What are the main characteristics of basophils?
Obscured nucleus
No lysosomes or phagocytic ability.
Contain surface IgE receptors - binding of IgE from B-cells in asthma or allergic reactions causes release of histamine and other allergy mediators
What is released from the large basophilic specific granules?
Heparin- anticoagulant
Histamine & heparin sulfate- vasodilators
Leukotrienes- constrict smooth muscles of pulmonary airways, maintain inflammation
What are the RBC cytoskeletal elements that make it flexible?
Spectrin, adductin, ankyrin
Integral membrane proteins: glycophorin C and band 3
Changes in which RBC cytoskeletal element with age triggers old RBC elimination by macrophages?
Glycophorin
How are blood types determined structurally?
Glycoproteins and glycolipid antigens (A,B, O) attached to glycophorins
How long do RBCs live and how are they destroyed?
120 days
Destroyed by spleen, bone marrow, liver macrophages (90%)
What gene is involved in spherocytosis?
Spectrin gene mutation
What gene is involved in elliptocytosis?
Band 4.1 gene mutation
Where does hematopoesis occur and how does that change with age?
Red bone marrow.
With age, appendicular bone marrow is replaced w yellow bone marrow, so most hematopoesis occurs in axial skeleton
What are the sites of hematopoesis from beginning embryonic development to middle age?
- Yolk sac (1st month)
- Liver (some spleen)
- Bone marrow (birth)
a. All bones in children
b. Only axial bones in adults- primarily vertebra > sternum > ribs
What are the 5 stages of erythropoesis?
- Proerythroblast
- Basophilic erythroblast
- Polychromatophilic erythroblast
- Orthochromatophilic erythroblast
- Reticulocyte
What happens during erythropoesis?
- Cells become smaller
- decrease in RNA
- increased Hbg
- cell divisions stop w normoblast
- Reticulocyte matures in blood and spits out nucleus
What stimulates erythropoesis and how?
ERYTHROPOETIN
- Hypoxemia (⬇️O2 transport)
- Liver and kidneys secrete EPO
- EPO stimulates red bone marrow
- ⬆️ erythropoesis and RBC count
- ⬆️ O2 transport
