WBCs Flashcards
Characteristics of Leukocytes (WBCs) (5)
1) Only formed elements that are COMPLETE CELLS (RBCs= anucleate & thrombocytes= cell fragments)
2) Do not contain Hemoglobin
3) Can reproduce
4) Produced in red bone marrow
5) Can engage in Phagocytosis
Lifespan of Different types of WBCs
NEB IS SHORT –> few days because they die off as they fight bacteria
Monocytes & Lymphocytes can live years & some can last entire lifetime
Differential White Blood Cell Counts (NLMEB)
-Neutrophils= 60-70%
- Lymphocytes= 20- 25%
- Monocytes= 3-8%
- Eosinophils= 4%
- Basophils= 0.5-1%
Diapedesis
- special function of Leukocytes
- Involves pavementing (margination) of a WBC against the inner lining of a capillary, followed by movement of the WBC through gaps between the cells of the capillary wall and into surrounding tissues
Chemotaxis
Attraction of leukocytes to specific chemicals which causes Diapedesis
What is the normal WBC count?
Leukocytosis vs. Leukopenia
- 5,000-10,000 WBCs per uL (microliter)
- Leukocytosis- increase in WBCs above 10,000 per uL (caused by infection or inflammation)
- Leukopenia- decrease in WBCs below 5,000 uL (caused by shock, radiation, or chemotherapy)
What are the 2 classes of Leukocytes & their characteristics?
1) Granulocytes (Neutrophils, Basophils, & Eosinophils) = granules in their cytoplasm & “loved” nuclei
2) Agranulocytes (Lymphocytes & Monocytes)= no granules & large, somewhat rounded nuclei
Neutrophils (6)
1) aka Polymorphonuclear Leukocytes or PMNs or polys
2) 60-70% of WBCs (most common)
3) Large cells with pale purple granules & 2 - 5 lobes in nucleus
4) First WBC to reach the site of an injury
5) Very active phagocytes
6) Granulocyte
Basophils (4)
1) 0.5-1% of all WBCs (least common)
2) Dark purple granules & horseshoe-shaped nucleus
3) Greatly involved in allergy –> release histamine to cause inflammation
4) Granulocyte
Eosinophils (4)
1) 2-4% of all WBCs
2) Red/orange granules & distinct biolobed nucleus
3) Designed to fight parasitic worms & involved in asthmatic responses
4) Granulocyte
Lymphocytes (6)
1) 20-25% of all WBCs
2) Large, rounded nucleus with little cytoplasm
3) Found in lymphoid tissues (spleen, lymph nodes, tonsils, GI tract)
4) B cells, T cells, & NK cells are types
5) Involved in regulating immunity, kill foreign cells, & antibody production
6) Agranulocyte
Monocytes (5)
1) 3-8% of WBCs
2) Large, irregular cell with large oval or heart shaped nuclues
3) Arrive after Neurtophils and more of them come at site of injury
4) After diapedesis, become macrophages
5) Agranulocyte
Thrombocytes (Platelets) (what are they, production site, lifespan, shape, number, characteristic (6))
1) Fragments of a Megakaryocyte (precursor cell)
2) Produced in red bone marrow
3) Lifespan= 5-9 days
4) Round/Oval disk-shaped cells
5) Anucleate
6) 150,000 - 400,000 per uL
Thrombopoeitin
Hormone that controls production of Thrombocytes (platelets)
Function of Thrombocytes (platelets) (2)
1) Help initiate blood clotting
2) Can release serotonin, Ca, & other chemicals to help decrease blood flow to an injured blood vessel AKA Degranulation
Hemopoiesis
- Blood cell formation aka Hematopoiesis
Pluripotent Stem Cell
-Undifferentiated cell where all blood cells arise from.
- Divide & differentiate to form all the formed elements
Where does hemopoiesis occur in embryo, fetus, & end fetal stage/life?
Embryo= yolk sac
Early Fetus= liver, spleen, thymus, & lymph nodes
Late Feuts/Life= Red Bone Marrow
What are the major sites of red bone marrow?
Sternum, ribs, pelvis, vertebrae, & proximal epiphyses of humerus & femur
Hemostasis (2)
1) Process of the stoppage of bleeding that prevents hemorrhaging using a positive feedback loop
1) Vessel injury –> Vascular Spasm –> Platelet Plug Formation –> Coagulation/Blood Clotting
Vascular Spasm (2)
1) Immediate vasoconstriction of a blood vessel (usually an artery) after injury.
2) Prevents excessive blood loss for up to 30 minutes
What triggers a Vascular Spasm? (4)
1) Injury to a vascular smooth muscle
2) Chemicals released by platelets
3) Reflexes triggered by pain receptors
4) Blood vessel compression caused by a build up of escaped blood in surrounding tissues
Platelet Plug Formation (2)
1) production of plug-like collection of platelets that helps prevent blood loss from a vessel
2) positively charged platelets attracted to negatively charged collagen fibers stick together and build up
Process of Platelet Plug Formation (4, sentences)
1) Negatively charged collagen fibers exposed to the lumen when blood vessel is damaged
2) Positively charged platelets cling to collagen fibers due to attraction from opposite charge
3) Platelets swell & become sticky
4) Platelets “degranulate,” releasing chemicals (serotonin & Ca) to enhance the vascular spasm while attracting more platelets
Process of Platelet Plug Formation (4, short)
1) Platelet Adhesion
2) Platelet release reaction (Degranulation)
3) Platelet Aggregation
4) Platelet Plug
Blood clotting (Coagulation)
- formation of a gel-like network of protein fibers (blood clot)
- Prevents blood loss while stabilizing platelet plug with Fibrin (mesh network of proteins)
- Involves blood proteins called Clotting Factors (plasma proteins produced by the liver)
What occurs inside lumen that prevents platelets from sticking normally?
Nitric Oxide & Prostacyclin released by endothelial cells inside lumen prevent them from sticking together or on blood vessel walls
Common Clotting Pathway (5, sentences)
1) During Degranulation of platelets, calcium ions are released and trigger production of Prothrombin Activator (enzyme) into bloodstream
2) Prothrombin Activator converts Prothombin (a clotting factor) into Thrombin (an active enzyme)
3) Thrombin converts Fibrinogen (a clotting factor) into Fibrin (a protein)
4) Fibrin forms a clot
5) Clot is stabilized by Factor XIII (chemical) via Syneresis
Common Clotting Pathway (PPTFF)
Platelet Degranulation –> Calcium ions –> Prothrombin Activator –> Prothrombin –> Thrombin –> Fibrinogen –>Fibrin –> Clot (stabilized via Synersis with Factor XIII)
What happens when a healed blood vessel no longer needs a clot?
-Fibrinolysis= blood clot dissolves via Plasmin (enzyme)
Intrinsic Pathway (4)
1) Factors needed for clotting found within the blood
2) Result of a minor injury to blood vessel lining
3) Triggered by negatively charged surfaces (collagen)
4) Occurs slowly (since so many steps)
Extrinsic Pathway (4)
1) Factors needed for clotting found outside the body
2) Result of greater injury
3) Triggered by exposing blood Tissue Factor (chemical found in tissues underneath damaged endothelium)
4) Faster process because skips several steps
What is common in both intrinsic & extrinsic clotting pathways?
Both require calcium ions and form Prothrombin Activator during the last step
Clot Retraction
- Platelets contain contracting proteins (actin & myosin) which contract to squeeze serum our of the clot.
- Then compact it & pull the sides of the damaged vessel together.
The buffy coat of a centrifuged blood sample is composed of (2)
Platelets & Leukocytes
The combination of Hemoglobin & Carbon Dioxide is
Carbaminohemoglobin
The oxygenated form of Hemoglobin is..
Oxyhemoglobin
What formed elements do NOT have chromosomes?
Erythrocytes, Reticulocytes, & Thrombocytes
What is the antigen involved in the Rh blood group
-D antigen
- Rh positive if D antigen present on RBCs
Antigens vs. Antibodies
-Antigens are on the surfaces of RBCs
-Antibodies are located in plasma (they bind)
Agglutination
Clumping of cells that occurs when antigens and antibodies form molecular bridges that connects cells
