The document summarizes the types and functions of white blood cells (leukocytes) and platelets. There are two main types of leukocytes - granulocytes which have granules and include neutrophils, eosinophils, and basophils, and agranulocytes which lack granules and include lymphocytes and monocytes. Platelets are fragments of megakaryocytes that initiate clot formation through a process involving vascular constriction, platelet plug formation, and coagulation of fibrin to form a blood clot and stop bleeding. Disorders can involve excessive clotting leading to thromboembolism or inadequate clotting causing bleeding.

1. LEUKOCYTES
White blood cells (WBCs)
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2. Leukocytes
• Make up <1% of total blood volume
• Buffy coat
• Increase in number (↑) b/c of infection
• Two types:
1.Granulocytes
2.Agranulocytes
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3. Granulocytes
• Granulocytes: neutrophils, eosinophils, and
basophils
• Granules in cytoplasm
• Wright’s stain
• Larger than RBCs
• Lobed nuclei
• Phagocytic
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4. Neutrophils
• Most numerous WBCs
• aka. Polymorphonuclear leukocytes (PMNs)
• Lobed nucleus
• ↑ during acute infections
• Phagocytic
• bacteria eaters
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5. Eosinophils
• Red-staining
• bilobed nuclei
• Digest parasitic worms
• ↑ Allergies
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6. Basophils
• Rarest WBCs
• Large, purplish-black granules
• contain histamine
• Histamine: inflammatory,
attracts other WBCs
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7. Agranulocytes
• Agranulocytes: lymphocytes and monocytes
• Lack visible granules
• Have spherical nuclei
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8. Lymphocytes
• Large, dark-purple, circular nuclei with thin, blue cytoplasm
• Two types of lymphocytes:
• T cells, act against viruses
• B cells, produce antibodies
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9. Monocytes
• The largest leukocytes
• Large pale-blue cytoplasm
• Dark purple U-shaped nuclei
• ↑ chronic infections
• Phagocytes & activators
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10. Leukopoiesis
• Production of
WBCs
• All blood cells form
from
hemocytoblasts
• Directed by
chemical
messages
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11. Leukemia
• Cancer of WBCs
• Uncontrolled growth of leukocytes
• Nonfunctional WBCs accumulate
• Death from infections
• Named by type of WBC
• Lymphocytic leukemia = lymphocytes
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12. PLATELETS
And clot formation
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13. Platelets
• Small fragments of megakaryocytes
• Small an irregularly shaped
• Thrombopoietin regulates formation
• Initiate clot formation
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14. Clot Formation
Clot Formation aka. hemostasis
Fast steps to stop bleeding
1. Vascular spasm
2. Platelet plug formation
3. Coagulation (blood clotting)
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15. Vascular Spasm
• Vasoconstriction of damaged blood vessel
• Caused by injury or pain
Platelet Plug Formation
• Stick to exposed fibers
• Swell, become spiked and sticky
• release chemical messengers
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16. Coagulation
• Blood goes from liquid to gel
•
Prothrombin  thrombin (protein modification)
•
Causes formation of a fiber mesh
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17. Hemostasis
Step 1 Vascular spasm
• Smooth muscle contracts,
causing vasoconstriction.
Collagen
fibers
Step 2 Platelet plug
formation
• Injury to lining of vessel
exposes collagen fibers;
platelets adhere.
• Platelets release chemicals
that make nearby platelets
sticky; platelet plug forms.
Platelets
Fibrin
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Step 3 Coagulation
• Fibrin forms a mesh that traps
red blood cells and platelets,
forming the clot.
Figure 16.13

18. Clotting Disorders
1. Thromboembolytic disorders:
• Clots or “thrombus” form in unbroken vessels
• Embolisms – floating thrombus
• Help prevent with aspirin
1. Bleeding disorders:
• prevent normal clotting
• Hemophilia
• Hereditary bleeding disorders
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