Final answer:
Healthy blood flows in a laminar fashion, which is smooth and consistent, while arterial blood is pulsed due to heartbeats. The endothelium of blood vessels prevents coagulation during circulation by producing substances that inhibit platelet aggregation and through its smooth surface.
Step-by-step explanation:
Healthy blood flows in a laminar fashion, which means it moves in layers and in one direction without much turbulence under normal conditions. This type of blood flow is smooth and consistent, which helps in the efficient delivery of oxygen and nutrients to tissues as well as the removal of waste products. Arterial blood flow is indeed pulsed due to the pumping action of the heart, but within the circulatory system, particularly in smaller blood vessels, blood flow strives to maintain a laminar state.
The endothelium of the blood vessel walls plays a crucial role in maintaining blood in a fluid state as it circulates. The endothelial cells produce substances like prostacyclin and nitric oxide which inhibit platelet aggregation and vasodilation, respectively. Additionally, the endothelium has a smooth surface that discourages platelets from sticking and initiating the coagulation cascade, which only gets activated when there is a breach in the vessel wall due to injury.
In summary, blood flow through the body is regulated in part by chemical signals and the physical characteristics of the blood vessel walls to prevent unnecessary coagulation, while blood pressure is regulated through various physiological mechanisms, including heart action, blood volume, and resistance of the bloodstream.