Blood chapter 19 part 2 Flashcards
- What is the difference between leukopenia, leukocytosis, and Leukemia
Leukopenia- not enough white blood cells do to bleeding or difficientsy
Leukocytosis- To many WBC
Leukemia-(EXtreme Leukocytosis) a cancer of the body’s blood forming system (usually WBCs formed in excess and released as immature forms)
- Which type of WBC is NOT produced from a myeloid stem cell?
Lymphocytes are produced from lymphoid stem cells
What do myeloid stem cells produce?
RBCs
Platelets
All WBCs except lymphocytes
- What specific hormone will promote the development of granulocytes from myeloid stem cells?
G-CFM
- What happens to an erythroblast just prior to it entering circulation?
It loses its nucleus
- When does a monocyte truly become a mature cell? When do Granulocytes?
When it migrates into a peripheral tissue. Granulocytes stay in the red marrow until they are mature
- Lymphoid stem cells are created in red bone marrow. Where do lymphocytes typically mature?
Lymphoid stem cells can migrate from red marrow to other lymph tissues (spleen, thymus, lymph nodes).
- Hormones stimulate the production of most WBC. What stimulates the production of lymphocytes?
Antigen or antibody presentation
What are platelets shaped like? How long is there lifespan? How many are there?
Non-nucleated, spindle-shaped cell fragments, 4 um in length and 1 um thick
Platelets have a lifespan of 9-12 days, and a normal circulating platelet count = 350,000/ul
•Release chemicals to initiate and control the clotting process
•Aggregate to form temporary patches (platelet plug) in wall of damaged blood vessels
•Actin and myosin filaments within platelets contract after a blood clot is formed to reduce the size of the vessel wall damage
- Describe the typical inactive platelet?
Really small compared to red blood cell spindle shape
- What is a typical normal platelet count?
35,000 platelets per microliter
- What specific signal can stimulate platelet production by megakaryocytes.
•Megakaryocytes are stimulated to do so by Thrombopoietin (TPO), a hormone produced by kidneys that accelerates platelet formation
How do megakaryocytes create platelets and how many do they make?
- Platelets are produced by megakaryocytes shedding bits of membrane-enclosed cytoplasm.
- Each megakaryocyte will produce about 4000 platelets.
- Define Hemostasis
Hemostasis is a process which causes bleeding to stop. It is the first stage of wound healing.
- What are the three phases of hemostasis?
- Vascular Phase
- Platelet Phase
- Coagulation Phase
- What happens during the vascular phase of hemostasis?
- Damage to a vessel wall causes a local contraction (shrinking) referred to as a vascular spasm
- The vascular spasm lasts about 30 minutes and includes:
- Contraction of endothelial cells to expose underlying basement membrane
- Release of both clotting factors and growth factors (hormones to promote regrowth)
- Endothelial cell membranes become “sticky”
- What happens during the platelet phase of hemostasis?
- Starts with attachment of platelets to sticky endothelial cells, exposed basement membrane and collagen fibers (platelet adhesion)
- Continued platelet aggregation leading to platelet plug
- Platelet activation includes:
- They become more spherical and extend cytoplasmic processes (they look hairy)
- They release ADP, thromboxane A, serotonin, clotting and growth factors (PDGF), and calcium ions to promote further aggregation and repair
- Prostacyclin and other factors work to limit the size of the platelet plug
- What happens during the coagulation phase of hemostasis?
Coagulation or blood clotting
- What is the importance of compounds like antithrombin-III heparin, and thrombin?
Limit coagulation process from getting out of hand
- What is the source of activation of the intrinsic pathway?
•Intrinsic pathway – Enzymes (Factor XII) activated by exposure to revealed collagen fibers
- What is the source of activation of the Extrinsic pathway
•Extrinsic pathway – Tissue factor (Factor III) released from damaged endothelial cells
- What do we call the process of clot dissolution?, and what enzyme is responsible?
Fibrinolysis is the process of clot dissolution
The Enzyme Plasmin is responsible
