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blood part 3

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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