Blood and lymphoid tissue Flashcards
Albumin
Carrier protein
Stays in blood stream
Hydrophilic
Where do RBCs come from?
Reticulocytes
How do RBCs develop?
Cells in kidney can measure O2 in blood and will initiate erythropoiesis
Erythropoiesis
- Form reticulocyte in bone marrow
- Released into blood stream to mature
What are leukocytes made from?
Progenitor cells
Lymphoid progenitors
Differentiate into lymphocytes and released in bloodstream
Fully mature in lymphoid organs
What are the lymphoid organs?
Thymus, spleen
Myeloid progenitors
Differentiate into other WBCs
Monocytes released into blood stream and mature
Granulocytes mature in bone marrow
- Some immature ones are reserved in bone marrow and activated/released when needed
What are platelets formed from?
Megakaryocytes
Stimulated by thrombopoietin
Stages of hemostasis
- Vessel spasm to control blood loss
- Formation of platelet plug
- Requires vWF
- Fibrinogen
- vWF binds to subendothelial portion of blood vessel
- Hooks grab the platelets
- Fibrinogen binds to 2B3A receptor on platelet and binds one to the next
- Fibrin fills holes between - Coagulation cascade
Coagulation cascade
Prothrombin -> thrombin
Thrombin converts fibrinogen -> fibrin
What is the intrinsic pathway stimulated by?
Blood injury
- Slower
What influences the intrinsic pathway?
Heparin
What is the extrinsic pathway stimulated by?
Tissue factor released by endothelial cells in response to injury or inflammatory process
- Faster
What influences the extrinsic pathway?
Coumadin
What should you check to evaluate the extrinsic pathway?
Prothrombin time
What should you check to evaluate the intrinsic pathway?
Partial thromboplastin time
What enzyme is important for clotting?
Ca++
What regulates coagulation?
Antithrombin III
Protein C
Protein S
What does Antithrombin III do?
Inactivates coagulation factors and thrombin
What does Protein C do?
Inactivates factors V and VIII
What does Protein S do?
Accelerates Protein C
Clot dissolution
Fibrinolysis causes plasminogen -> plasmin
- Digests fibrin strands
- Digests several clotting factors
What does TPA do?
Medication that speeds up plasminogen to dissolve blood clots
What is primary thrombocytosis?
An abnormally high level of free thrombopoietin due to abnormal thrombopoietin receptors on platelets