Vazodilatáció

Vazodilatáció, a vasodilation or more commonly blood vessel dilation, refers to the widening of blood vessels. This process is a crucial physiological mechanism that helps to regulate blood flow and blood pressure. When blood vessels dilate, their internal diameter increases, allowing more blood to pass through. This can occur in arteries, veins, and even smaller capillaries.

The primary cause of vasodilation is the relaxation of the smooth muscle tissue that surrounds the blood vessels. This relaxation can be triggered by various factors, including chemical signals. For example, nitric oxide is a potent vasodilator, released by the endothelium (the inner lining of blood vessels) in response to certain stimuli like increased blood flow or specific hormones. Other substances like histamine, prostaglandins, and acetylcholine can also induce vasodilation.

Physiologically, vasodilation serves several important functions. It is essential for increasing blood supply to tissues that require more oxygen and nutrients, such as during exercise. It also plays a role in thermoregulation, helping the body to dissipate heat by increasing blood flow to the skin's surface. Furthermore, vasodilation is a key mechanism in lowering blood pressure; when vessels widen, resistance to blood flow decreases. Conversely, the opposite process, vasoconstriction, involves the narrowing of blood vessels.