17.4-17.5 Leukocytes/Platelets Flashcards
Formed element that is a complete cell with nuclei and organelles
A.k.a = WBCs
Function: defense against disease
Leukocytes
Abnormally low WBC count
Leukopenia
Contain visible cytoplasmic granules
Basophils, Eosinophils, Neutrophils
Granulocytes
Do not contain visible cytoplasmic granules
Monocytes, Lymphocytes
Agranulocytes
Production of white blood cells
Stimulated by 2 messengers:
- Interleukins (IL)
- Colony stimulating factors (CSF)
Leukopoiesis
Stem cells that produce lymphocytes
Lymphoid stem cells
Stem cells that produce all other elements
Myeloid stem cells
Mature in bone marrow
B lymphocytes
Plasma cells
Mature in the thymus
T lymphocytes
Effector T cells
Cancerous condition involving overproduction of abnormal WBCs
Without treatment, all leukemias are fatal
Cancerous cells fill red bone marrow
Leukemia
Highly contagious viral disease
“Kissing disease”
Caused by Epstein-Barr virus
Involve lymphocytes that become enlarged
Runs its course with rest in 4-6 weeks
Symptoms: Enlargement of spleen, tiredness, aches, low fever
Leukocyte mononucleosis
Cytoplasmic fragments of megakaryocytes
Blue staining outer-region; purple granules
Form temporary platelet plug that helps seal breaks in blood vessels
Contain several chemicals involved in clotting process
Platelet
Mitosis of cells occurs, but no cytokinesis –> forms large cell with multi-lobed nucleus
Stage IV megakaryocyte sends cytoplasmic projections into lumen of capillary
Projections break into platelet fragments
Platelet formation
Fast series of reactions for stoppage of bleeding following an injury
Three steps:
1. Vascular spasm
2. Platelet formation
3. Coagulation (blood clotting)
LS: 100-120 days
Erythrocyte
- Vascular Spasm - smooth muscle contracts causing vasconstriction
- Platelet plug - Injury of lining of vessel exposes collagen fibers; platelets adhere
- Platelets release chemicals
- Coagulation - Fibrin forms a mesh that traps the red blood cells and platelets, forming clot
How a clot forms
Occurs in 3 phases
Triggered by tissue-damaging events
Stage 1: Intrinsic or extrinsic pathway
Stage 2: Prothrombin activator
Stage 3: Sticky fibrin formation
Coagulation
Vessel endothelium ruptures, exposing underlying tissues
Platelets cling and their surfaces provide sites for mobilization factors
Inside
Intrinsic pathway
Tissue cell trauma exposes blood to tissue factor
Extrinsic pathway
Stage 2 of coagulation; Prothrombin activator catalyzes transformation of plasma protein prothrombin into active enzyme thrombin
Prothrombin activator
Stage 3 of coagulation; Thrombin catalyzes transformation of soluble clotting factor fibrinogen into insoluble fibrin
Ends with formation of fibrin mesh
Sticky fibrin mesh formation
Draws ruptured blood vessel edges together
Vessel healing even as a clot retraction occurs
Clot retraction
Process whereby clots are removed after repair is completed
Begins within 2 days and continues for several days until clot is dissolved
Fibrin dissolves
Fibrinolysis
- Swift removal and dilution of clotting factors
- Inhibition of activated clotting factors
*Limiting amount of thrombin produced
Reducing clot size
Disorders from undesirable clot formation
Thromboembolic disorders
Abnormalities that prevent normal clot formation
Bleeding disorders
Involves both types of disorders; Widespread coagulation in intact blood vessels, blocking blood flow
Can occur in septicemia, incompatible blood transfusions, or complications in pregnancy
Disseminated intravascular coagulation (DIC)
Clot that develops and persists in unbroken blood vessel
May block circulation, leading to tissue death
Thrombus
Thrombus freely floating in bloodstream
Causes embolisms - Embolus obstructing a vessel
Risk factors: atherosclerosis, inflammation, slowly flowing blood or blood stasis from immobility
Embolus
Used to prevent undesirable clotting
Ex. aspirin, heparin, warfarin, dabigatran
Anticoagulant drugs
Deficient number of circulating platelets
Red spots appear on skin as a result of widespread hemorrhages
Due to suppression or destruction of red bone marrow
Platelet count = <50,000/microliter
Thrombocytopenia
Includes several similar hereditary bleeding disorders
Symptoms: prolonged bleeding, especially into joint cavities
Treatment: Introduction of genetically engineered factors
Hemophilia
LS: 6 hours to a few days
Neutrophils
LS: 5 days
Granulocyte
Orange/purple granules
Eosinophil
LS: a few hours to a few days
Granulocyte
Blue
Basophil
LS: hours to years
Cells for lymphatic system
Lymphocyte
LS: Months
Monocyte
LS: 5-10 days
Small
Platelet
