Leukocytes, Platelets, Hemostasis Flashcards
How many leukocytes typically exist in a microliter of blood?
4,800 to 10,800 per 1 µl of blood
Define diapedesis and chemotaxis.
Positive Chemotaxis: phenomenon in which damaged/infected cells provide a chemical trail for leukocytes to follow
Diapedesis: how leukocytes cross blood vessel walls to travel to areas of need
What is the term for an elevated WBC count? A depleted WBC count?
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Know the 5 types of leukocytes – which ones are granulocytes? Agranulocytes? What is their order of abundance? What are some specific functions of each type?
Granulocytes: leukocytes that contain membrane-bound granules in the cytoplasm
Neutrophils: most numerous WBCs, phagocytes that destroy acute infection
Eosinophils: fight parasitic worm infections
Basophils: rarest WBCs, contain the chemical Histamine
Agranulocytes: leukocytes that do not contain granules in the cytoplasm
Lymphocytes: live in lymphatic tissues, play an important role in immunity
Monocytes: largest WBCs, fight chronic infections
What stimulates the creation of leukocytes?
Chemical messengers called interleukins or colony-stimulating factors (CSFs) trigger the creation of leukocytes
What types of blood cells differentiate from the myeloid line? From the lymphoid?
Hemocytoblasts are quickly differentiated into lymphoid and myeloid stem cells
Myeloid stem cells give rise to erythrocytes, platelets, monocytes, and all the granulocytes
Be familiar the lineage lines of leukocytes – from slides 7 and 8.
Roughly define leukemia. What causes it? What are some symptoms?
Leukemia: overproduction of abnormal leukocytes
Typically, excessive leukocytes are descendants of a single cell undergoing un-regulated proliferation
Excessive leukocytes impair normal function of red bone marrow
Symptoms: severe anemia, bleeding, fever, weight loss, and bone pain
The fatality of leukemia is typically associated with internal hemorrhage or overwhelming infection
Types: acute, chronic, myeloid, and lymphocytic
The more serious, acute forms of leukemia primarily impact children
State the general premise of chemotherapy. How does it work?
Where do platelets come from? How long do they typically live? What is their essential function?
Like erythrocytes, platelets are NOT technically cells
Platelets are fragments of very large cells, called megakaryocytes
The granules contained in platelets play important roles in blood-clotting
Without platelets, blood loss from an injured or damaged blood vessel would continue indefinitely
Platelets age quickly and degenerate within ~10 days
What are the 3 steps hemostasis? What happens after blood successfully clots?
Three steps must occur in rapid sequence:
Vascular Spasm
Platelet Plug Formation
Coagulation
Following successful hemostasis, the blood clot will retract and dissolve
The clot is replaced by fibrous tissue, which more permanently prevents blood loss
Name two things that have anti-coagulant properties. Name a natural anticoagulant found in endothelial cells. Name two aggregating agents.
Adenosine Diphosphate (ADP): a potent aggregating agent
Serotonin and thromboxane A: messengers that enhance both vascular spasm and platelet aggregation
What works to stabilize a forming platelet plug? What works to reinforce a formed platelet plug?
The platelet plug is reinforced with fibrin threads
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What mineral is essential to the formation of a blood clot?
Vitamin K is required for synthesizing 4 different clotting factors
Know the 3 steps of coagulation including what enzymes are involved.
slide 24
