-
—low WBC count: below 5,000 WBCs/mL
–Causes: radiation, poisons, infectious disease
–Effects: elevated risk of infection
Leukopenia
-
—high WBC count: above 10,000 WBCs/mL
–Causes: infection, allergy, disease
Leukocytosis
-
—cancer of hemopoietic tissue that
usually produces an extraordinary high number of circulating leukocytes and
their precursors
Leukemia
-
What are the four kinds of leukemia? What are teh effects?
- –Myeloid leukemia: uncontrolled granulocyte production
- –Lymphoid leukemia: uncontrolled lymphocyte or monocyte production
- –Acute leukemia: appears suddenly, progresses rapidly, death within months
- –Chronic leukemia: undetected for months, survival time 3 years
- –Effects: normal cell percentages disrupted; impaired clotting; opportunistic infections
-
—the cessation of bleeding
–Stopping potentially fatal leaks
–Hemorrhage: excessive bleeding
Hemostasis
-
•Three hemostatic mechanisms
- –Vascular spasm
- –Platelet plug formation
- –Blood clotting (coagulation)
-
—small fragments of megakaryocyte cells
Platelets
-
–Stem cells (that develop receptors for thrombopoietin) become megakaryoblasts
•Thrombopoiesis
-
–Repeatedly replicate DNA without
dividing
–Form gigantic cells called
megakaryocytes with a multilobed nucleus
•100 mm in diameter, remains in bone
marrow
•Megakaryoblasts
-
—live in bone marrow adjacent to blood sinusoids
–Long tendrils of cytoplasm (proplatelets)
protrude into the blood sinusoids: blood flow splits off fragments called
platelets
–Circulate freely for 10 days
–40% are stored in spleen
Megakaryocytes
-
•Clot retraction occurs within __ minutes
30
-
—dissolution of a clot
–Factor XII speeds up formation of kallikrein enzyme
–Kallikrein converts plasminogen
into plasmin, a fibrin-dissolving enzyme that breaks up the clot
Fibrinolysis
-
—abnormal clotting in unbroken vessel
Thrombosis
-
–clot
•Most likely to occur in leg veins
of inactive people
Thrombus
-
–clot may break free, travel from veins to lungs
Pulmonary embolism
-
—anything that can travel in the blood and block blood vessels
Embolus
-
(tissue death) may occur if clot blocks blood supply to an organ (MI or stroke)
–650,000 Americans die annually of
thromboembolism (traveling blood clots)
Infarction
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