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Leukocytes

Leukocytes leave capillaries through diapedesis

Move through tissues to sites of infection

Leukocytosis: WBC count >11,000/μl blood

Diapedesis

to walk thru process where WBC leave and move into tissues

Neutrophils

Phagocytize bacteria, fungi
Numbers increase during acute bacterial infections

most common WBC in bloodstream
70% in Bloodstream
has multi-lobe in the nucleus 3-5 lobes
*Granulocytes*

Eosinophils

-Attack parasitic worms
-hot pink different from other cells
-has bi-lobe nucleus
-destroy things that are large
-secrete digestive enzymes on worms in body
*Granulocytes*

Basophils

-Granules contain histamine
-most rare are less than1% WBC in b.s.
-b/c it is os pack you cant find the nucleus and they are large WBC
*Granulocytes*

Lymphocytes

-Most found in lymphatic system, not blood stream
-Can be either T lymphocytes or B lymphocytes
- common same size as RBC
*Agranulocytes*

Monocytes

Differentiate into macrophages
Defend against viruses, intracellular bacterial parasites and chronic infections
* Agranulocytes*

Leukopoiesis

Stimulated by chemicals produced by infected tissues

Occurs in bone marrow

Granulocytes have short lifespans; agranulocytes may live for months to decades
-- live half a day max 10 days--

leukopoiesis

production of leukocytes

Leukocyte Formation

-All leukocytes arise from the hemocytoblast
-Early branching separates lymphocyte from all other leukocytes or myeloid stem cell

Myeloblast stage

Committed cells
Accumulate lysosomes

lysosmes

sac that contain enzymes

Promyelocyte stage

Have lysosomes

Myelocyte stage

Distinctive granules of each granulocyte type appear

Band cell stage

Nuclei arc

Mature Granulocytes

Stored in the bone marrow

Nuclei constrict just before entering the bloodstream

Lifespan of 0.5 to 9.0 days

Monocyte Formation:

Diverge from myeloblasts that may become monocytes or neutrophils

Promonocyte: commit cll leave bone marrow early stage

Monocyte:immature leave bone marrow and go to b.s. and complete development in spleen and lymph organ

Macrophage:phagocytic cells capable taking in substance that are harmful and destroy them cell w/in cell

Lymphocyte Formation:

Lymphoid stem cell

Lymphoblast

Prolymphocyte (leaves bone marrow)

Lymphocyte (differentiates in lymphoid tissue)

Plasma cells- produce antibodies essential proteins to protect the body against infection

Leukopenia

abnormally low wbc count

Leukocyte Disorders

Cancer treatments
Chemo, radiation therapy

Illness
Influenza, lupus, malaria, others

Certain meds
Glucocorticoids (have immunosupressive and anti-inflammatory properties)

Platelets

Not whole cells—just cell fragments

Have chemical containing granules

Essential for blood clotting

Production of Platelets

Begins with a hemocytoblast stem cell

Megakaryoblast

undergoes several mitotic divisions without cytokinesis
*Production of Platelets*

Promegakaryocyte

accumulate granules
*Production of Platelets*

Megakaryocyte

cytoplasm is compartmentalized by membranes.
*Production of Platelets*

Megakaryocyte2

plasma membrane fragments, releasing platelets
*Production of Platelets*

Hemostasis

Hemostasis Stoppage of bleeding

Vascular spasm

-immediate vasoconstriction in response to injury
-get muscular contraction to stop or limit the blood lost in the body

Coagulation

transforms blood from liquid to gel

Vascular spasm2

Triggered by:
-Injury to vascular smooth muscle

-Chemicals released by endothelial cells and platelets

-Reflexes initiated by local pain receptors

Platelet Plug Formation

Normally, platelets do not stick to each other or to the inside lining of blood vessels (the endothelium)

When the endothelium is damaged and underlying collagen exposed, platelets adhere to the collagen fibers

The adhering platelets produce chemicals that attract even more platelets to the area

Coagulation2

Platelets in platelet plug produce PF3

Tissues below the damaged endothelium secrete tissue factor

The plasma contains Ca2+ and clotting factors

When all four of these compounds are present, a chemical called prothrombin activator is formed.

thrombin (an enzyme)

Coagulation3

Prothrombin activator converts prothrombin (a
plasma protein) into thrombin (an enzyme)

Coagulation4

Thrombin catalyzes the joining of fibrinogen molecules in plasma into a fibrin mesh

The fibrin mesh traps erythrocytes, effectively sealing the blood vessel hole

Coagulation5

-12 clotting factors, numbered 1-13
-Most synthesized by the liver
-Need vitamin K for synthesis

Thromboembolic disorders

Undesirable clot formation

Bleeding disorders

Prevent normal clot formation

Thrombus

a clot that
develops and persists in an
unbroken blood vessel

Embolus

a clot that floats
freely in the blood

Embolism

a clot that is
obstructing a vessel

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