THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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activated platelets release chemicals that inhibit blood clot formation
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activated platelets release chemicals the inhibit cell division in damaged tissue
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activated platelets constrict blood vessels, stopping blood flow
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activated platelets release chemicals that activate more platelets
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Detailed explanation-1: -As the platelets continue to amass, more of the chemicals are released and more platelets are attracted to the site of the clot. The positive feedback accelerates the process of clotting until the clot is large enough to stop the bleeding.
Detailed explanation-2: -Which of the following predictions about the activity of platelets best describes a positive feedback mechanism? Activated platelets release chemicals that activate more platelets.
Detailed explanation-3: -For instance, activated platelets will secrete abundant adenosine diphosphate (ADP) and adenosine triphosphate (ATP) from their dense granule that in turn can activate neighboring platelets via ADP and ATP sensitive receptors.
Detailed explanation-4: -Platelets also store and transport several chemicals, including serotonin, epinephrine, histamine, and thromboxane; upon activation these molecules are released and initiate local blood vessel constriction, which facilitates clot formation.