The video explains the response of blood vessels to injury, focusing on the role of endothelial cells in maintaining normal blood flow and preventing unnecessary coagulation. It details the mechanisms by which endothelial cells inhibit platelet aggregation and clotting, and describes the processes of vascular spasm and platelet plug formation following vessel damage. The video also covers the activation and aggregation of platelets, setting the stage for further discussions on coagulation cascades in subsequent videos.

What is the primary function of endothelial cells in healthy blood vessels?

• To decrease blood flow

• To prevent unnecessary coagulation and platelet aggregation

• To promote blood clotting

• To increase blood pressure

Which enzyme is responsible for breaking down ADP in healthy blood vessels?

• NTP DS1

• Thromboxane synthase

• Phospholipase A2

• Cyclooxygenase

What role does nitric oxide play in blood vessels?

• It causes vasoconstriction

• It acts as a vasodilator and inhibits platelet aggregation

• It promotes platelet aggregation

• It breaks down clotting factors

How does thrombomodulin affect thrombin activity?

• It inhibits thrombin production

• It modulates thrombin to break down clotting factors

• It converts thrombin into a clotting factor

• It enhances thrombin's ability to form clots

What is the function of anti-thrombin III in blood vessels?

• To degrade clotting factors

• To increase ADP concentration

• To activate clotting factors

• To promote platelet aggregation

What is the initial response of blood vessels to injury?

• Platelet plug formation

• Vascular spasm

• Endothelial cell regeneration

• Coagulation cascade

Which chemical is released by damaged endothelial cells to promote vasoconstriction?

• Endothelium

• ADP

• Prostacyclin

• Nitric oxide

What is the role of von Willebrand factor in platelet plug formation?

• It activates thromboxane A2

• It releases serotonin

• It binds to collagen and platelets

• It breaks down ADP

What triggers platelet aggregation after adhesion?

• Secretion of prostacyclin

• Change in glycoprotein 1B conformation

• Binding of thrombin

• Release of nitric oxide

What is the next step after platelet plug formation in the coagulation process?

• Endothelial cell repair

• ADP breakdown

• Vascular spasm

• Coagulation cascade