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Vasculogenesis is the process of blood vessel formation, occurring by a de novo production of endothelial cells. [1] It is the first stage of the formation of the vascular network, closely followed by angiogenesis. [2] [3]
Blood vessels transport blood cells, nutrients, and oxygen to most of the tissues of a body. They also take waste and carbon dioxide away from the tissues. [2] Some tissues such as cartilage, epithelium, and the lens and cornea of the eye are not supplied with blood vessels and are termed avascular.
These endothelial products include nitric oxide and endothelin-1 that are released in response to either chemical stimuli, like histamine, or increased shear stress on the blood vessel (meaning the amount of stress exerted by blood on the blood vessel walls). While nitric oxide causes vasodilation, endothelin-1 causes vasoconstriction.
Vasodilation is the opposite of vasoconstriction, which is the narrowing of blood vessels. When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output [further explanation needed]. Vascular resistance is the amount of force circulating blood must overcome in order to allow ...
In vertebrates, the circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. [1] [2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and Latin vascula meaning vessels).
Hemostasis occurs when blood is present outside of the body or blood vessels. It is the innate response for the body to stop bleeding and loss of blood. During hemostasis three steps occur in a rapid sequence. Vascular spasm is the first response as the blood vessels constrict to allow less blood to be lost.
Differences in vascular permeability between normal tissue and a tumor. Vascular permeability, often in the form of capillary permeability or microvascular permeability, characterizes the capacity of a blood vessel wall to allow for the flow of small molecules (drugs, nutrients, water, ions) or even whole cells (lymphocytes on their way to the site of inflammation) in and out of the vessel.
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.