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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.
Vascular smooth muscle contracts or relaxes to change both the volume of blood vessels and the local blood pressure, a mechanism that is responsible for the redistribution of the blood within the body to areas where it is needed (i.e. areas with temporarily enhanced oxygen consumption).
In the walls of blood vessels, and lymph vessels, (excluding blood and lymph capillaries) it is known as vascular smooth muscle. There is smooth muscle in the tracts of the respiratory, urinary, and reproductive systems. In the eyes, the ciliary muscles, iris dilator muscle, and iris sphincter muscle are types of smooth muscles.
The closure of the aortic valve causes a rapid change in pressure in the aorta called the incisura. This short sharp change in pressure is rapidly attenuated down the arterial tree. The pulse wave form is also reflected from branches in the arterial tree and gives rise to a dicrotic notch in main arteries.
Baroreceptors respond very quickly to maintain a stable blood pressure, but their responses diminish with time and thus are most effective for conveying short term changes in blood pressure. In people with essential hypertension the baroreceptors and their reflexes change and function to maintain the elevated blood pressure as if normal. The ...
The smallest contractile unit in the fiber is called the sarcomere which is a repeating unit within two Z bands. The sarcoplasm also contains glycogen which provides energy to the cell during heightened exercise, and myoglobin , the red pigment that stores oxygen until needed for muscular activity.
The vasomotor center is a collection of integrating neurons in the medulla oblongata of the middle brain stem.The term "vasomotor center" is not truly accurate, since this function relies not on a single brain structure ("center") but rather represents a network of interacting neurons.
The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure causes the heart rate to decrease. Decreased blood pressure decreases baroreflex activation and causes heart ...