1.2 Blood (leukocytes) Flashcards
composition of leukocytes in body
what ypes are there?
omplete cells that make up 1% of the total blood volume
Leukocytosis - WBC count over 11,000 cells/ mm3
types : Neutrophils (50-70%), Lymphocytes (25-45%), Monocytes (3-8%), Eosinophils (2-4%), Basophils (0.5 - 1%)
” Never Let Monkeys Eat Bananas ^ in order of % comp
what are the Granulocytes
what characteristics do tehy have in common
neutrophils, eosinophils, and basophils
- have ctyoplasmic granules -> stain red (acidic), blue (basic) or both with wrights stain
- are larger and more short lived than RBCs
- have lboed nuclei
- are all phagocytic cells
describe neutrophils and their hematology
*granulocyte
- have multilobed nucelus
- have 2 types of granules that take up aciidc and basic dyes -> cytoplasm is lilac
- contain peroxidases, hydrolytic enzymes and defensins (antibiotic-like proteins)
*body’s bacteria slayers, phagocytes
how do neutrophils act to phagocytize bacteria
- bacteria secretes chemotoxic molecules that attract neutrophils and activate them -> get extravasation
*extravasation: happes after they adhere and spead along capillary wall, they sequeeze between endothelial cells of capillary -> phagocytosis of bacteria
What are esoinophils
*granulocyte
Have bilobed nuclei connected via a broad band
- Have red (acidophilic) large, coarse granules
- Help combat multicellular parasites and certain infections
- Along with mast cells, they also control mechanisms associated with allergy and asthma
What are Basophils
*granulocyte
- Have U- or S-shaped nuclei and are similar to mast cells
- Have large, purplish-black (basophilic) granules (histamine)
- Histamine - inflammatory chemical that acts as a vasodilator and attracts other WBCs
What are Agranulocytes
- Includes lymphocytes and monocytes:
- Lack visible cytoplasmic granules
- Are similar structurally, but are functionally distinct and unrelated cell types
- Have spherical nuclei (lymphocytes) or kidney-shaped nuclei (monocytes)
What are lymphocytes
*agranulocyte
- mount immune response by direct cell attack or via antibodies
- Dark-purple nuclei with a thin rim of blue cytoplasm
- Most cells are found in lymphoid tissue (spleen, lymphocytes, some in the blood)
- There are two types of lymphocytes:
- > T cells - function in the immune response (adaptive: cytotoxic & Helper)
- > B cells - give rise to plasma cells, which produce antibodies
what are monocytes
*agrunulocyte
The largest leukocytes that have purple- staining, U- or kidney-shaped nuclei
- Leave the circulation (diapedesis) and differentiate into macrophages
- Macrophages are highly mobile and actively phagocytic
- Can activate lymphocytes by secreting chemical signals
what are platelets
- Megakaryocyte: produces platelets in bone marrow sinus
* does not leave bone marrow, has projections to blood stream -> forms platelets
- Platelets: are cell fragments with no nucleus and have granules, mitochondria, glycogen and cytoskeleton
Descirbe the granules in platelets?
What are the function of platelets?
- contain two types fo granules: alpha (clotting factors) and dense core (histamine)
- Alpha grandles contain serotonin, Ca2+, enzymes, ADP, and platelet-derived growth factor (PDGF)
Function: clot formation, bind to injured blood vessel wall, aggregate with RBCs forms hemostatic plug (stops bleeding)
What inactivates platelets
- platelets are kept inactive by NO and prostacylcin (PGI2)
comparison of leukocytes
(a) Neutrophil (multilobed nucleus, lightly stained granules)
(b) Eosinophil (biloded nuclei, dark stained granules)
(c) Basophil (very dark overal, granules stain dark)
(d) Small lymphocyte (msotly nucleus)
(e) Monocyte (kidney shaped)
how are leukocytes produced
Leukopoiesis is stimulated by interleukins and colony- stimulating factors (CSFs OR CFU)
- > interleukins are numbers (e.g., IL-1, IL-2)
- > CSFs are named for the WBCs they stimulate (e.g., granulocyte-CSF stimulates granulocytes)
- > Macrophages and T-cells are the most important sources of cytokines
- Many hematopoietic hormones are used clinically to stimulate bone marrow
* can stimualte WBC to treat disease
how are macrophages formed
hemocytoblas (pluripotent stem cell) -> myeloid stem cell -> granulocyte macrophage
-> monoblast -> macrophage
*in bone marrow
how are neutrophils formed
hemocytoblas (pluripotent stem cell) -> myeloid stem cell -> granulocyte macrophage
-> myeloblast -> neutrophil
How are Eosinophils produced
hemocytoblas (pluripotent stem cell) -> myeloid stem cell -> eosinophil
how are paltelets formed
hemocytoblas (pluripotent stem cell) -> myeloid stem cell -> Megakaryocyte -> megakaryoblast -> platelets
