<unk>  is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss. When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular resistance. This makes the skin turn paler because less blood reaches the surface, reducing the radiation of heat. On a larger level,<unk>  is one mechanism by which the body regulates and maintains mean arterial pressure. Medications causing<unk> , also known as vasoconstrictors, are one type of medicine used to raise blood pressure. Generalized<unk>  usually results in an increase in systemic blood pressure, but it may also occur in specific tissues, causing a localized reduction in blood flow. The extent of<unk>  may be slight or severe depending on the substance or circumstance. Many vasoconstrictors also cause pupil dilation. Medications that cause<unk>  include: antihistamines, decongestants, and stimulants. Severe<unk>  may result in symptoms of intermittent claudication.
Vasoconstriction
Vasodilation
Osteostimulation
Vasoactivity
Cytostasis
Lymphangiogenesis
Nociception
Vascular recruitment